Thu, 07 Aug 2008 21:32:31 BST CiteULike: Tag ventral_striatum http://www.citeulike.org/tag/ventral_striatum CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/suizan/article/1022473 <i>J Neurosci, Vol. 26, No. 51. (20 December 2006), pp. 13213-13217.</i><br /><br />Discounting future outcomes as a function of their deferred availability underlies much of human decision making. Discounting, or preference for immediate over delayed rewards of larger value, is often associated with impulsivity and is a risk factor for addictive disorders such as pathological gambling, cigarette smoking, and drug and alcohol abuse. The ventral striatum (VS) is involved in mediating behavioral responses and physiological states associated with reward, and dysregulation of the VS contributes to addiction, perhaps by affecting impulsive decision-making. Behavioral tests of delay discounting (DD), which index preference for smaller immediate over larger delayed rewards, covary with impulsive tendencies in humans. In the current study, we examined the relationship between individual differences in DD, measured in a behavioral assessment, and VS activity measured with blood oxygenation level-dependent functional magnetic resonance imaging, in 45 adult volunteers. VS activity was determined using a task involving positive and negative feedback with monetary reward. Analyses revealed that individual differences in DD correlate positively with magnitude of VS activation in response to both positive and negative feedback, compared with a no-feedback control condition. Variability in DD was also associated with differential VS activation in response to positive, compared with negative, feedback. Collectively, our results suggest that increased preference for smaller immediate over larger delayed rewards reflects both a relatively indiscriminate and hyper-reactive VS circuitry. They also highlight a specific neurocognitive mechanism that may contribute to increased risk for addiction. Preference for immediate over delayed rewards is associated with magnitude of ventral striatal activity. AR Hariri SM Brown DE Williamson JD Flory H de Wit SB Manuck doi:10.1523/JNEUROSCI.3446-06.2006 J Neurosci, Vol. 26, No. 51. (20 December 2006), pp. 13213-13217. 2007-01-02T20:20:02-00:00 2006 J Neurosci 1529-2401 26 51 13213 13217 addiction decision_making fmri ventral_striatum http://www.citeulike.org/user/suizan/article/467922 <i>Neuron, Vol. 49, No. 1. (5 January 2006), pp. 157-166.</i><br /><br />Food preferences are acquired through experience and can exert strong influence on choice behavior. In order to choose which food to consume, it is necessary to maintain a predictive representation of the subjective value of the associated food stimulus. Here, we explore the neural mechanisms by which such predictive representations are learned through classical conditioning. Human subjects were scanned using fMRI while learning associations between arbitrary visual stimuli and subsequent delivery of one of five different food flavors. Using a temporal difference algorithm to model learning, we found predictive responses in the ventral midbrain and a part of ventral striatum (ventral putamen) that were related directly to subjects' actual behavioral preferences. These brain structures demonstrated divergent response profiles, with the ventral midbrain showing a linear response profile with preference, and the ventral striatum a bivalent response. These results provide insight into the neural mechanisms underlying human preference behavior. Predictive neural coding of reward preference involves dissociable responses in human ventral midbrain and ventral striatum. JP O'doherty TW Buchanan B Seymour RJ Dolan doi:10.1016/j.neuron.2005.11.014 Neuron, Vol. 49, No. 1. (5 January 2006), pp. 157-166. 2006-01-18T01:28:49-00:00 2006 Neuron 0896-6273 49 1 157 166 neural-coding reward ventral_striatum http://www.citeulike.org/user/suizan/article/464595 <i>Ann NY Acad Sci, Vol. 877, No. 1. (29 June 1999), pp. 33-48.</i><br /><br />The concept of the ventral striatum was first put forth by Heimer and Wilson to describe the extension of basal ganglia elements into the olfactory tubercle. The ventral striatum includes the conventional nucleus accumbens, which has been closely associated with reward and motivation. This paper uses the afferent connections to the ventral striatum to define this region in monkeys. Furthermore the shell and core subterritories are discussed with respect to their histochemistry and specific connections. The Concept of the Ventral Striatum in Nonhuman Primates Suzanne Haber Nikolaus Mcfarland Ann NY Acad Sci, Vol. 877, No. 1. (29 June 1999), pp. 33-48. 2006-01-13T21:43:49-00:00 1999 Ann NY Acad Sci 877 1 33 48 motivation reward ventral_striatum http://www.citeulike.org/user/oamg/article/1355835 <i>Hum Brain Mapp, Vol. 27, No. 4. (April 2006), pp. 306-313.</i><br /><br />A prominent theory in neuroscience suggests reward learning is driven by the discrepancy between a subject's expectation of an outcome and the actual outcome itself. Furthermore, it is postulated that midbrain dopamine neurons relay this mismatch to target regions including the ventral striatum. Using functional MRI (fMRI), we tested striatal responses to prediction errors for probabilistic classification learning with purely cognitive feedback. We used a version of the Rescorla-Wagner model to generate prediction errors for each subject and then entered these in a parametric analysis of fMRI activity. Activation in ventral striatum/nucleus-accumbens (Nacc) increased parametrically with prediction error for negative feedback. This result extends recent neuroimaging findings in reward learning by showing that learning with cognitive feedback also depends on the same circuitry and dopaminergic signaling mechanisms. Ventral-striatal/nucleus-accumbens sensitivity to prediction errors during classification learning. PF Rodriguez AR Aron RA Poldrack doi:10.1002/hbm.20186 Hum Brain Mapp, Vol. 27, No. 4. (April 2006), pp. 306-313. 2007-06-01T15:45:39-00:00 2006 Hum Brain Mapp 1065-9471 27 4 306 313 instrumental_conditioning nucleus_accumbens reinforcement_learning reward_prediction_error ventral_striatum http://www.citeulike.org/user/oamg/article/1202838 <i>Neuron, Vol. 38, No. 4. (22 May 2003), pp. 625-636.</i><br /><br />A growing body of evidence implicates the ventral striatum in using information acquired through associative learning. The present study examined the activity of ventral striatal neurons in awake, behaving rats during go/no-go odor discrimination learning and reversal. Many neurons fired selectively to odor cues predictive of either appetitive (sucrose) or aversive (quinine) outcomes. Few neurons were selective when first exposed to the odors, but many acquired this differential activity as rats learned the significance of the cues. A substantial proportion of these neurons encoded the cues' learned motivational significance, and these neurons tended to reverse their firing selectivity after reversal of odor-outcome contingencies. Other neurons that became selectively activated during learning did not reverse, but instead appeared to encode specific combinations of cues and associated motor responses. The results support a role for ventral striatum in using the learned significance, both appetitive and aversive, of predictive cues to guide behavior. Neural Encoding in Ventral Striatum during Olfactory Discrimination Learning Barry Setlow Geoffrey Schoenbaum Michela Gallagher doi:10.1016/S0896-6273(03)00264-2 Neuron, Vol. 38, No. 4. (22 May 2003), pp. 625-636. 2007-04-02T13:37:40-00:00 2003 Neuron 38 4 625 636 appetitive aversive reinforcement_learning reward striatal striatum ventral_striatum http://www.citeulike.org/user/oamg/article/481104 <i>Exp Brain Res, Vol. 85, No. 3. (1991), pp. 491-500.</i><br /><br />The sources of input and the behavioral effects of lesions and drug administration suggest that the striatum participates in motivational processes. We investigated the activity of single striatal neurons of monkeys in response to reward delivered for performing in a go-nogo task. A drop of liquid was given each time the animal correctly executed or withheld an arm movement in reaction to a visual stimulus. Of 1593 neurons, 115 showed increased activity in response to delivery of liquid reward in both go and nogo trials. Responding neurons were predominantly located in dorsal and ventromedial parts of anterior putamen, in dorsal and ventral caudate, and in nucleus accumbens. They were twice as frequent in ventral as compared to dorsal striatal areas. Responses occurred at a median latency of 337 ms and lasted for 525 ms, with insignificant differences between dorsal and ventral striatum. Reward responses differed from activity recorded in the face area of posterior putamen which varied synchronously with individual mouth movements. Responses were directly related to delivery of primary liquid reward and not to auditory stimuli associated with it. Most of them also occurred when reward was delivered outside of the task. These results demonstrate that neurons of dorsal and particularly ventral striatum are involved in processing information concerning the attribution of primary reward. Responses to reward in monkey dorsal and ventral striatum. P Apicella T Ljungberg E Scarnati W Schultz Exp Brain Res, Vol. 85, No. 3. (1991), pp. 491-500. 2006-01-25T22:59:31-00:00 1991 Exp Brain Res 0014-4819 85 3 491 500 basal_ganglia monkey neurophysiology reward striatum ventral_striatum http://www.citeulike.org/user/oamg/article/1806523 <i>Seminars in Neuroscience, Vol. 4, No. 2. (April 1992), pp. 119-127.</i><br /><br />Manipulations of dopamine levels in the dorsal and ventral striatum are shown to affect the activation of behaviour in distinct, yet parallel ways, which depend upon the nature of the neocortical and limbic input to these structures. Whereas dopamine in the dorsal striatum contributes to the sensorimotor co-ordination of consummatory behaviour and the development of a `response set' in motor preparatory processes for skilled responses, dopamine in the ventral striatum influences the impact of reward-related stimuli on appetitive aspects of behaviour. The circumstances under which the striatal dopamine projections are normally active to effect these functions are defined by studies which attempt to correlate firing in single units or neurochemical indices of dopamine activity with environmental conditions, internal states and behaviour. Functions of dopamine in the dorsal and ventral striatum Trevor Robbins Barry Everitt doi:10.1016/1044-5765(92)90010-Y Seminars in Neuroscience, Vol. 4, No. 2. (April 1992), pp. 119-127. 2007-10-22T14:02:38-00:00 1992 Seminars in Neuroscience 4 2 119 127 dopamine dorsal_striatum striatum ventral_striatum http://www.citeulike.org/user/oamg/article/479097 <i>Trends Neurosci, Vol. 27, No. 8. (August 2004), pp. 468-474.</i><br /><br />Since its conception three decades ago, the idea that the striatum consists of a dorsal sensorimotor part and a ventral portion processing limbic information has sparked a quest for functional correlates and anatomical characteristics of the striatal divisions. But this classic dorsal-ventral distinction might not offer the best view of striatal function. Anatomy and neurophysiology show that the two striatal areas have the same basic structure and that sharp boundaries are absent. Behaviorally, a distinction between dorsolateral and ventromedial seems most valid, in accordance with a mediolateral functional zonation imposed on the striatum by its excitatory cortical, thalamic and amygdaloid inputs. Therefore, this review presents a synthesis between the dorsal-ventral distinction and the more mediolateral-oriented functional striatal gradient. Putting a spin on the dorsal-ventral divide of the striatum. P Voorn LJ Vanderschuren HJ Groenewegen TW Robbins CM Pennartz doi:10.1016/j.tins.2004.06.006 Trends Neurosci, Vol. 27, No. 8. (August 2004), pp. 468-474. 2006-01-25T02:36:21-00:00 2004 Trends Neurosci 0166-2236 27 8 468 474 dorsal_striatum review striatum ventral_striatum http://www.citeulike.org/user/oamg/article/488875 <i>Science, Vol. 304, No. 5669. (16 April 2004), pp. 452-454.</i><br /><br />Instrumental conditioning studies how animals and humans choose actions appropriate to the affective structure of an environment. According to recent reinforcement learning models, two distinct components are involved: a "critic," which learns to predict future reward, and an "actor," which maintains information about the rewarding outcomes of actions to enable better ones to be chosen more frequently. We scanned human participants with functional magnetic resonance imaging while they engaged in instrumental conditioning. Our results suggest partly dissociable contributions of the ventral and dorsal striatum, with the former corresponding to the critic and the latter corresponding to the actor. Dissociable roles of ventral and dorsal striatum in instrumental conditioning. J O'Doherty P Dayan J Schultz R Deichmann K Friston RJ Dolan doi:10.1126/science.1094285 Science, Vol. 304, No. 5669. (16 April 2004), pp. 452-454. 2006-02-01T20:02:54-00:00 2004 Science 1095-9203 304 5669 452 454 dorsal_striatum instrumental_conditioning ventral_striatum http://www.citeulike.org/user/oamg/article/1272277 <i>Neurosci Biobehav Rev, Vol. 26, No. 3. (May 2002), pp. 321-352.</i><br /><br />Emotions are multifaceted, but a key aspect of emotion involves the assessment of the value of environmental stimuli. This article reviews the many psychological representations, including representations of stimulus value, which are formed in the brain during Pavlovian and instrumental conditioning tasks. These representations may be related directly to the functions of cortical and subcortical neural structures. The basolateral amygdala (BLA) appears to be required for a Pavlovian conditioned stimulus (CS) to gain access to the current value of the specific unconditioned stimulus (US) that it predicts, while the central nucleus of the amygdala acts as a controller of brainstem arousal and response systems, and subserves some forms of stimulus-response Pavlovian conditioning. The nucleus accumbens, which appears not to be required for knowledge of the contingency between instrumental actions and their outcomes, nevertheless influences instrumental behaviour strongly by allowing Pavlovian CSs to affect the level of instrumental responding (Pavlovian-instrumental transfer), and is required for the normal ability of animals to choose rewards that are delayed. The prelimbic cortex is required for the detection of instrumental action-outcome contingencies, while insular cortex may allow rats to retrieve the values of specific foods via their sensory properties. The orbitofrontal cortex, like the BLA, may represent aspects of reinforcer value that govern instrumental choice behaviour. Finally, the anterior cingulate cortex, implicated in human disorders of emotion and attention, may have multiple roles in responding to the emotional significance of stimuli and to errors in performance, preventing responding to inappropriate stimuli. Emotion and motivation: the role of the amygdala, ventral striatum, and prefrontal cortex. RN Cardinal JA Parkinson J Hall BJ Everitt Neurosci Biobehav Rev, Vol. 26, No. 3. (May 2002), pp. 321-352. 2007-05-02T15:27:04-00:00 2002 Neurosci Biobehav Rev 0149-7634 26 3 321 352 amygdala emotion motivation prefrontal_cortex ventral_striatum http://www.citeulike.org/user/nelmor/article/2599022 <i>Nat Neurosci, Vol. 11, No. 4. (April 2008), pp. 423-425.</i> Emotional environments retune the valence of appetitive versus fearful functions in nucleus accumbens Sheila Reynolds Kent Berridge doi:10.1038/nn2061 Nat Neurosci, Vol. 11, No. 4. (April 2008), pp. 423-425. 2008-03-26T15:35:40-00:00 2008 Nat Neurosci 11 4 423 425 Nature Publishing Group aversive fear-conditioning reward ventral_striatum http://www.citeulike.org/user/nelmor/article/2524523 <i>Neuron, Vol. 57, No. 5. (13 March 2008), pp. 774-785.</i><br /><br />Summary The motivation to seek cocaine comes in part from a dysregulation of reward processing manifested in dysphoria, or affective withdrawal. Learning is a critical aspect of drug abuse; however, it remains unclear whether drug-associated cues can elicit the emotional withdrawal symptoms that promote cocaine use. Here we report that a cocaine-associated taste cue elicited a conditioned aversive state that was behaviorally and neurophysiologically quantifiable and predicted subsequent cocaine self-administration behavior. Specifically, brief intraoral infusions of a cocaine-predictive flavored saccharin solution elicited aversive orofacial responses that predicted early-session cocaine taking in rats. The expression of aversive taste reactivity also was associated with a shift in the predominant pattern of electrophysiological activity of nucleus accumbens (NAc) neurons from inhibitory to excitatory. The dynamic nature of this conditioned switch in affect and the neural code reveals a mechanism by which cues may exert control over drug self-administration. Behavioral and Electrophysiological Indices of Negative Affect Predict Cocaine Self-Administration Robert Wheeler Robert Twining Joshua Jones Jennifer Slater Patricia Grigson Regina Carelli doi:10.1016/j.neuron.2008.01.024 Neuron, Vol. 57, No. 5. (13 March 2008), pp. 774-785. 2008-03-13T09:21:58-00:00 2008 Neuron 57 5 774 785 aversive cocaine ventral_striatum http://www.citeulike.org/user/nelmor/article/2362220 <i>Neuron, Vol. 57, No. 3. (7 February 2008), pp. 432-441.</i><br /><br />Summary A neuroanatomical principle of striatal organization has been established through which ventral domains, including the nucleus accumbens, exert control over dorsal striatal processes mediated by so-called "spiraling," striato-nigro-striatal, circuitry. We have investigated the functional significance of this circuitry in the control over a cocaine-seeking habit by using an intrastriatal disconnection procedure that combined a selective, unilateral lesion of the nucleus accumbens core and infusion of a dopamine receptor antagonist into the contralateral dorsolateral striatum, thereby disrupting striato-midbrain-striatal serial connectivity bilaterally. We show that this disconnection selectively decreased drug-seeking behavior in rats extensively trained under a second-order schedule of cocaine reinforcement. These data thereby define the importance of interactions between ventral and dorsal domains of the striatum, mediated by dopaminergic transmission, in the neural mechanisms underlying the development and performance of cocaine-seeking habits that are a key characteristic of drug addiction. Cocaine Seeking Habits Depend upon Dopamine-Dependent Serial Connectivity Linking the Ventral with the Dorsal Striatum David Belin Barry Everitt doi:10.1016/j.neuron.2007.12.019 Neuron, Vol. 57, No. 3. (7 February 2008), pp. 432-441. 2008-02-11T10:34:40-00:00 2008 Neuron 57 3 432 441 cocaine dopamine dorsal_striatum striatum ventral_striatum http://www.citeulike.org/user/nelmor/article/2905947 <i>J. Neurosci., Vol. 28, No. 25. (18 June 2008), pp. 6372-6382.</i><br /><br />Spontaneous "off-line" reactivation of neuronal activity patterns may contribute to the consolidation of memory traces. The ventral striatum exhibits reactivation and has been implicated in the processing of motivational information. It is unknown, however, whether reactivating neuronal ensembles specifically recapitulate information relating to rewards that were encountered during wakefulness. We demonstrate a prolonged reactivation in rat ventral striatum during quiet wakefulness and slow-wave but not rapid eye movement sleep. Reactivation of reward-related information processed in this structure was particularly prominent, and this was primarily attributable to spike trains temporally linked to reward sites. It was accounted for by small, strongly correlated subgroups in recorded cell assemblies and can thus be characterized as a sparse phenomenon. Our results indicate that reactivated memory traces may not only comprise feature- and context-specific information but also contain a value component. 10.1523/JNEUROSCI.1054-08.2008 Preferential Reactivation of Motivationally Relevant Information in the Ventral Striatum Carien Lansink Pieter Goltstein Jan Lankelma Ruud Joosten Bruce Mcnaughton Cyriel Pennartz doi:10.1523/JNEUROSCI.1054-08.2008 J. Neurosci., Vol. 28, No. 25. (18 June 2008), pp. 6372-6382. 2008-06-18T18:22:40-00:00 2008 J. Neurosci. 28 25 6372 6382 replay reward ventral_striatum http://www.citeulike.org/user/nelmor/article/210656 <i>Nature Neuroscience, Vol. 8, No. 6. (22 May 2005), pp. 805-812.</i> Dopaminergic modulation of limbic and cortical drive of nucleus accumbens in goal-directed behavior Yukiori Goto Anthony Grace doi:10.1038/nn1471 Nature Neuroscience, Vol. 8, No. 6. (22 May 2005), pp. 805-812. 2005-05-25T19:50:13-00:00 2005 Nature Neuroscience 1097-6256 8 6 805 812 Nature Publishing Group dopamine hippocampus pfc ventral_striatum http://www.citeulike.org/user/nelmor/article/2520173 <i>J Neurosci, Vol. 15, No. 5 Pt 1. (May 1995), pp. 3622-3639.</i><br /><br />The interactions among excitatory inputs arising from the prefrontal cortex, amygdala, and hippocampus, and innervating nucleus accumbens neurons were studied using in vivo intracellular recording techniques. Neurons recorded in the accumbens displayed one of three activity states: (1) silent, (2) spontaneously firing at low, constant rates, or (3) a bistable membrane potential, characterized by alternating periods of activity and silence occurring in concert with spontaneous transitions between two steady-state membrane potentials (average, -77.3 +/- 7.1 mV base, -63.0 +/- 7.4 mV plateau). These neurons also exhibited a high degree of convergence of responses elicited by stimulation of each of the three excitatory inputs tested. Activation of hippocampal afferents, but not cortical, amygdaloid, or thalamic afferents, induced bistable cells to switch to the depolarized (active) state. In contrast, no bistable cells were encountered in the nucleus accumbens following an acute transection of the fornix. Furthermore, microinjection of lidocaine in the vicinity of the hippocampal afferents at the level of the fornix caused a reversible elimination of the plateau phase in bistable cells. These data suggest that hippocampal input is necessary for accumbens neurons to enter a depolarized, active state. Furthermore, activation of prefrontal cortical inputs fail to evoke spike firing in accumbens neurons unless they are in this active state. Consequently, the hippocampus appears to be capable of gating prefrontal corticoaccumbens throughput. Synaptic interactions among excitatory afferents to nucleus accumbens neurons: hippocampal gating of prefrontal cortical input. P O'Donnell AA Grace J Neurosci, Vol. 15, No. 5 Pt 1. (May 1995), pp. 3622-3639. 2008-03-12T13:00:07-00:00 1995 J Neurosci 0270-6474 15 5 Pt 1 3622 3639 hippocampus upstate ventral_striatum http://www.citeulike.org/user/nelmor/article/2520167 <i>J Neurosci Methods, Vol. 137, No. 1. (15 August 2004), pp. 49-60.</i><br /><br />The nucleus accumbens (NAc) is an important component of circuitry that underlies reward related behaviors and the rewarding properties of drugs of abuse. Glutamatergic afferents to the nucleus are critical for its normal function and for behaviors related to drug addiction. An angled, sagittal mouse brain slice preparation has been designed to facilitate concurrent stimulation of two major glutamatergic afferent pathways to the nucleus accumbens. Medium spiny neurons at the medial core/shell boundary of the accumbens were depolarized by stimulation of either hippocampal or limbic cortical afferents through activation of AMPA-type glutamate receptors. High frequency but not low frequency stimulation of hippocampal afferents depolarized medium spiny neurons to a membrane potential that resembled the up state observed upon high frequency stimulation in vivo. The magnitude of the membrane depolarization was positively correlated with the amplitude of the stimulus-evoked EPSP. Concurrent stimulation of hippocampal and limbic cortical afferents at theta frequency selectively induced a long-term depression (LTD) in the magnitude of stimulus-evoked EPSPs on the hippocampal afferent only. These data suggest that this brain slice preparation can be used to study mechanisms underlying synaptic plasticity at two of the critical glutamatergic afferent synapses in the nucleus accumbens as well as characterizing potential interactions between afferents. Additionally, LTD at hippocampo-accumbens synapses can be induced at a stimulus frequency known to support reinstatement of drug seeking behavior. A novel mouse brain slice preparation of the hippocampo-accumbens pathway. RT Matthews O Coker DG Winder doi:10.1016/j.jneumeth.2004.02.001 J Neurosci Methods, Vol. 137, No. 1. (15 August 2004), pp. 49-60. 2008-03-12T12:57:58-00:00 2004 J Neurosci Methods 0165-0270 137 1 49 60 hippocampus in-vitro methods ventral_striatum http://www.citeulike.org/user/nelmor/article/1119261 <i>Neurosci Biobehav Rev, Vol. 13, No. 2-3. (l 1989), pp. 181-186.</i><br /><br />The histories of the terms "reward" and "reinforcement" are reviewed to show the difference in their origins. Reward refers to the fact that certain environmental stimuli have the property of eliciting approach responses. Evidence suggests that the ventral striatum (nucleus accumbens area) is central to the mediation of this behavior. Reinforcement refers to the tendency of certain stimuli to strengthen learned stimulus-response tendencies. The dorsolateral striatum appears to be central to the mediation of this behavior. Neuroanatomical and neurochemical data are adduced suggesting that reward may be mediated by a neural circuit including the neostriatal patch system, together with the hippocampus, limbic system (amygdala, prefrontal cortex) and ventral pallidum. The evidence also suggests that reinforcement, in the form of dopamine release in the striatal matrix, acts to promote the consolidation of sensori-motor associations. Thus, the matrix may mediate stimulus-response memory as part of a circuit including the cerebral cortex, substantia nigra pars reticulata and its projections to thalamic and brainstem motor areas. Reward or reinforcement: what's the difference? NM White Neurosci Biobehav Rev, Vol. 13, No. 2-3. (l 1989), pp. 181-186. 2007-02-23T20:17:02-00:00 1989 Neurosci Biobehav Rev 0149-7634 13 2-3 181 186 reinforcement review reward striatum ventral_striatum http://www.citeulike.org/user/nelmor/article/2968677 <i>J. Neurosci., Vol. 28, No. 27. (2 July 2008), pp. 6950-6959.</i><br /><br />The nucleus accumbens (NAc) has been implicated in a variety of associative processes that are dependent on the integrity of the amygdala and hippocampus (HPC). However, the extent to which the two subregions of the NAc, the core and shell, form differentiated circuits within the amygdala- and hippocampal-ventral striatal circuitry remains unclear. The present study investigated the effects of selective excitotoxic lesions of the nucleus accumbens shell or core subregion on appetitive elemental cue and context conditioning, shown previously to be dependent on the basolateral amygdala and hippocampus, respectively. Rats were trained sequentially to acquire discrete conditioned stimulus-sucrose conditioning, followed by spatial context-sucrose conditioning in a place preference apparatus characterized by three topographically identical chambers, the chambers being discriminable only on the basis of path integration. NAc shell lesions selectively impaired the acquisition of conditioned place preference and the use of spatial information to retrieve information about a discrete cue, whereas, as expected, NAc core lesions attenuated the acquisition of cue conditioning compared with sham rats. In a subsequent experiment, disconnection of the HPC from the NAc shell using unilateral asymmetric lesions of each structure resulted in a pattern of impairment in place conditioning and context-dependent cue retrieval similar to that produced by NAc shell lesions. These data not only suggest that the NAc core and shell subregions subserve distinct associative processes but also that the NAc shell and HPC are important functional components of a limbic corticostriatal network involved in spatial context conditioning. 10.1523/JNEUROSCI.1615-08.2008 Functional Interaction between the Hippocampus and Nucleus Accumbens Shell Is Necessary for the Acquisition of Appetitive Spatial Context Conditioning Rutsuko Ito Trevor Robbins Cyriel Pennartz Barry Everitt doi:10.1523/JNEUROSCI.1615-08.2008 J. Neurosci., Vol. 28, No. 27. (2 July 2008), pp. 6950-6959. 2008-07-07T08:13:45-00:00 2008 J. Neurosci. 28 27 6950 6959 conditioning hippocampus ventral_striatum http://www.citeulike.org/user/nelmor/article/1370039 <i>Neuroscience, Vol. 61, No. 3. (August 1994), pp. 533-545.</i><br /><br />The nucleus accumbens is a major component of the ventral striatum through which most of the limbic affiliated cortical areas gain access to the basal ganglia circuitry. In this study, the organization of the pathways linking the nucleus accumbens to the thalamus, via the substantia nigra pars reticulata, was examined in the rat using anatomical and electrophysiological methods. Use of anterograde and retrograde transport of wheatgerm agglutinin conjugated to horseradish peroxidase has established that the core of the nucleus accumbens innervates a dorsal region of the substantia nigra pars reticulata which projects to subfields of the mediodorsal and ventral medial thalamic nuclei. These subfields consist of the rostral pole of the mediodorsal nucleus with the exception of its central segment and a region of the ventral medial nucleus, medial to the mammillothalamic tract. Confirming the existence of a nucleus accumbens nigrothalamic link, we have observed that electrical or chemical stimulation of the nucleus accumbens induces an inhibition of the spontaneous discharges of the nigral cells which project to the mediodorsal and ventral medial thalamic nuclei. Finally, the cortical projections of the thalamic subfields involved in the nucleus accumbens nigrothalamic circuit were determined using the anterograde and retrograde axonal transport of wheatgerm agglutinin conjugated with horseradish peroxidase. These subfields innervate mainly the prelimbic and to a lesser degree the orbital areas of the prefrontal cortex. The present data show that the substantia nigra pars reticulata is a major link beteen the core of the nucleus accumbens and the prefrontal cortex and provide further evidence for the concept of a parallel architecture in the basal ganglia thalamocortical circuits of the ventral striatum. Indirect nucleus accumbens input to the prefrontal cortex via the substantia nigra pars reticulata: A combined anatomical and electrophysiological study in the rat JM Deniau A Menetrey AM Thierry Neuroscience, Vol. 61, No. 3. (August 1994), pp. 533-545. 2007-06-07T11:31:35-00:00 1994 Neuroscience 61 3 533 545 anatomy ofc pfc ventral_striatum http://www.citeulike.org/user/nelmor/article/2844657 <i>J. Neurosci., Vol. 28, No. 22. (28 May 2008), pp. 5623-5630.</i><br /><br />To make sound economic decisions, the brain needs to compute several different value-related signals. These include goal values that measure the predicted reward that results from the outcome generated by each of the actions under consideration, decision values that measure the net value of taking the different actions, and prediction errors that measure deviations from individuals' previous reward expectations. We used functional magnetic resonance imaging and a novel decision-making paradigm to dissociate the neural basis of these three computations. Our results show that they are supported by different neural substrates: goal values are correlated with activity in the medial orbitofrontal cortex, decision values are correlated with activity in the central orbitofrontal cortex, and prediction errors are correlated with activity in the ventral striatum. 10.1523/JNEUROSCI.1309-08.2008 Dissociating the Role of the Orbitofrontal Cortex and the Striatum in the Computation of Goal Values and Prediction Errors Todd Hare John O'Doherty Colin Camerer Wolfram Schultz Antonio Rangel doi:10.1523/JNEUROSCI.1309-08.2008 J. Neurosci., Vol. 28, No. 22. (28 May 2008), pp. 5623-5630. 2008-05-29T14:39:09-00:00 2008 J. Neurosci. 28 22 5623 5630 decision fmri ofc td value ventral_striatum http://www.citeulike.org/user/nelmor/article/1963685 <i>Neuropsychopharmacology, Vol. aop, No. current.</i> α6-Containing Nicotinic Acetylcholine Receptors Dominate the Nicotine Control of Dopamine Neurotransmission in Nucleus Accumbens Richard Exley Michael Clements Henrike Hartung Michael Mcintosh Stephanie Cragg doi:10.1038/sj.npp.1301617 Neuropsychopharmacology, Vol. aop, No. current. 2007-11-23T05:37:29-00:00 Neuropsychopharmacology 0893-133X aop current Nature Publishing Group acetylcholine dopamine dorsal_striatum nicotine striatum ventral_striatum http://www.citeulike.org/user/nelmor/article/1532690 <i>J. Neurosci., Vol. 27, No. 31. (1 August 2007), pp. 8174-8177.</i><br /><br />To explain investing decisions, financial theorists invoke two opposing metrics: expected reward and risk. Recent advances in the spatial and temporal resolution of brain imaging techniques enable investigators to visualize changes in neural activation before financial decisions. Research using these methods indicates that although the ventral striatum plays a role in representation of expected reward, the insula may play a more prominent role in the representation of expected risk. Accumulating evidence also suggests that antecedent neural activation in these regions can be used to predict upcoming financial decisions. These findings have implications for predicting choices and for building a physiologically constrained theory of decision-making. 10.1523/JNEUROSCI.1564-07.2007 Neural Antecedents of Financial Decisions Brian Knutson Peter Bossaerts doi:10.1523/JNEUROSCI.1564-07.2007 J. Neurosci., Vol. 27, No. 31. (1 August 2007), pp. 8174-8177. 2007-08-03T09:19:47-00:00 2007 J. Neurosci. 27 31 8174 8177 fmri human insula pfc review reward risk ventral_striatum http://www.citeulike.org/user/nelmor/article/1624810 <i>Neuropsychopharmacology, Vol. aop, No. current.</i> Drug Addiction as a Pathology of Staged Neuroplasticity Peter Kalivas Charles O'Brien doi:10.1038/sj.npp.1301564 Neuropsychopharmacology, Vol. aop, No. current. 2007-09-05T18:18:50-00:00 Neuropsychopharmacology 0893-133X aop current Nature Publishing Group dopamine drugs plasticity review ventral_striatum vta http://www.citeulike.org/user/nelmor/article/460432 <i>Neuron, Vol. 45, No. 4. (17 February 2005), pp. 587-597.</i><br /><br />The nucleus accumbens (NAc) is a key component of the brain's reward pathway, yet little is known of how NAc cells respond to primary rewarding or aversive stimuli. Here, naive rats received brief intraoral infusions of sucrose and quinine paired with cues in a classical conditioning paradigm while the electrophysiological activity of individual NAc neurons was recorded. NAc neurons (102) were typically inhibited by sucrose (39 of 52, 75%) or excited by quinine (30 of 40, 75%) infusions. Changes in firing rate were correlated with the oromotor response to intraoral infusions. Most taste-responsive neurons responded to only one of the stimuli. NAc neurons developed responses to the cues paired with sucrose and quinine. Thus, NAc neurons are innately tuned to rewarding and aversive stimuli and rapidly develop responses to predictive cues. The results indicate that the output of the NAc is very different when rats taste rewarding versus aversive stimuli. Nucleus accumbens neurons are innately tuned for rewarding and aversive taste stimuli, encode their predictors, and are linked to motor output. MF Roitman RA Wheeler RM Carelli doi:10.1016/j.neuron.2004.12.055 Neuron, Vol. 45, No. 4. (17 February 2005), pp. 587-597. 2006-01-09T22:58:17-00:00 2005 Neuron 0896-6273 45 4 587 597 aversive reward taste ventral_striatum http://www.citeulike.org/user/nelmor/article/1206070 <i>Trends in Neurosciences, Vol. In Press, Corrected Proof</i><br /><br />There are several brain regions that have been implicated in the control of motivated behavior and whose disruption leads to the pathophysiology observed in major psychiatric disorders. These systems include the ventral hippocampus, which is involved in context and focus on tasks, the amygdala, which mediates emotional behavior, and the prefrontal cortex, which modulates activity throughout the limbic system to enable behavioral flexibility. Each of these systems has overlapping projections to the nucleus accumbens, where these inputs are integrated under the modulatory influence of dopamine. Here, we provide a systems-oriented approach to interpreting the function of the dopamine system, its modulation of limbic-cortical interactions and how disruptions within this system might underlie the pathophysiology of schizophrenia and drug abuse. Regulation of firing of dopaminergic neurons and control of goal-directed behaviors Anthony Grace Stan Floresco Yukiori Goto Daniel Lodge doi:10.1016/j.tins.2007.03.003 Trends in Neurosciences, Vol. In Press, Corrected Proof 2007-04-04T14:05:09-00:00 Trends in Neurosciences In Press, Corrected Proof amygdala dopamine hippocampus pfc review ventral_striatum http://www.citeulike.org/user/nelmor/article/1413086 <i>Neuroscience & Biobehavioral Reviews, Vol. 31, No. 3. (2007), pp. 287-314.</i><br /><br />Neuronal nicotinic acetylcholine receptors (nAChRs) modulate dopaminergic function. Discovery of their multiplicity has lead to the search for subtype-selective nAChR agonists that might be therapeutically beneficial in diseases linked to brain dopaminergic pathways. The regulation and responses of the nigrostriatal and mesolimbic dopaminergic pathways are often similar, but some differences do exist. The cerebral distribution and characteristics of various nAChR subtypes differ between nigrostriatal and mesolimbic dopaminergic pathways. Comparison of nicotine and epibatidine, two nAChR agonists whose relative affinities for various nAChR subtypes differ, revealed differences in the nAChR-mediated regulation of dopaminergic activation between these dopamine systems. Nicotine preferentially stimulates the mesolimbic pathway, whereas epibatidine's stimulatory effect falls on the nigrostriatal pathway. Thus, it may be possible to stimulate the nigrostriatal pathway with selective nAChR agonists that do not significantly affect the mesolimbic pathway, and thus lack addictive properties. Furthermore, dopamine uptake inhibition revealed a novel inhibitory effect of epibatidine on accumbal dopamine release, which could form a basis for novel antipsychotics that could alleviate the elevated accumbal dopaminergic tone found in schizophrenia during the active psychotic state. Different regulation of nigrostriatal and mesolimbic dopaminergic pathways by nAChRs could be an important basis for developing novel drugs for treatment of Parkinson's disease and schizophrenia. Differential nicotinic regulation of the nigrostriatal and mesolimbic dopaminergic pathways: Implications for drug development Sanna Janhunen Liisa Ahtee Neuroscience & Biobehavioral Reviews, Vol. 31, No. 3. (2007), pp. 287-314. 2007-06-26T09:13:22-00:00 2007 Neuroscience & Biobehavioral Reviews 31 3 287 314 acetylcholine dopamine nicotine review striatum ventral_striatum http://www.citeulike.org/user/nelmor/article/2208709 <i>J Neurosci, Vol. 24, No. 29. (21 July 2004), pp. 6446-6456.</i><br /><br />Previously it has been shown that the hippocampus and neocortex can spontaneously reactivate ensemble activity patterns during post-behavioral sleep and rest periods. Here we examined whether such reactivation also occurs in a subcortical structure, the ventral striatum, which receives a direct input from the hippocampal formation and has been implicated in guidance of consummatory and conditioned behaviors. During a reward-searching task on a T-maze, flanked by sleep and rest periods, parallel recordings were made from ventral striatal ensembles while EEG signals were derived from the hippocampus. Statistical measures indicated a significant amount of reactivation in the ventral striatum. In line with hippocampal data, reactivation was especially prominent during post-behavioral slow-wave sleep, but unlike the hippocampus, no decay in pattern recurrence was visible in the ventral striatum across the first 40 min of post-behavioral rest. We next studied the relationship between ensemble firing patterns in ventral striatum and hippocampal ripples-sharp waves, which have been implicated in pattern replay. Firing rates were significantly modulated in close temporal association with hippocampal ripples in 25% of the units, showing a marked transient enhancement in the average response profile. Strikingly, ripple-modulated neurons in ventral striatum showed a clear reactivation, whereas nonmodulated cells did not. These data suggest, first, the occurrence of pattern replay in a subcortical structure implied in the processing and prediction of reward and, second, a functional linkage between ventral striatal reactivation and a specific type of high-frequency population activity associated with hippocampal replay. The ventral striatum in off-line processing: ensemble reactivation during sleep and modulation by hippocampal ripples. CM Pennartz E Lee J Verheul P Lipa CA Barnes BL McNaughton doi:10.1523/JNEUROSCI.0575-04.2004 J Neurosci, Vol. 24, No. 29. (21 July 2004), pp. 6446-6456. 2008-01-08T20:16:11-00:00 2004 J Neurosci 1529-2401 24 29 6446 6456 hippocampus replay spw-r striatum ventral_striatum http://www.citeulike.org/user/nelmor/article/868270 <i>Psychopharmacology (Berl) (16 September 2006)</i><br /><br />BACKGROUND: The nucleus accumbens is the ventral extent of the striatum, the main input nucleus of the basal ganglia. Recent hypotheses propose that the accumbens and its dopamine projection from the midbrain contribute to appetitive behaviors required to obtain reward. However, the specific nature of this contribution is unclear. In contrast, significant advances have been made in understanding the role of the dorsal striatum in action selection and decision making. OBJECTIVE: In order to develop a hypothesis of the role of nucleus accumbens dopamine in action selection, the physiology and behavioral pharmacology of the nucleus accumbens are compared to those of the dorsal striatum. HYPOTHESES: Three hypotheses concerning the role of dopamine in these structures are proposed: (1) that dopamine release in the dorsal striatum serves to facilitate the ability to respond appropriately to temporally predictable stimuli (that is, stimuli that are so predictable that animals engage in anticipatory behavior just prior to the stimulus); (2) that dopamine in the nucleus accumbens facilitates the ability to respond to temporally unpredictable stimuli (which require interruption of ongoing behavior); and (3) that accumbens neurons participate in action selection in response to such stimuli by virtue of their direct (monosynaptic inhibitory) and indirect (polysynaptic excitatory) projections to basal ganglia output nuclei. The nucleus accumbens as part of a basal ganglia action selection circuit. Saleem Nicola doi:10.1007/s00213-006-0510-4 Psychopharmacology (Berl) (16 September 2006) 2006-09-25T18:19:07-00:00 2006 Psychopharmacology (Berl) 0033-3158 dopamine dorsal_striatum reward ventral_striatum http://www.citeulike.org/user/klouie/article/334118 <i>European Journal of Neuroscience, Vol. 22, No. 6. (September 2005), pp. 1502-1512.</i> Neural correlates of the proximity and quantity of anticipated food rewards in the ventral striatum of domestic chicks Ei-Ichi Izawa Naoya Aoki Toshiya Matsushima doi:10.1111/j.1460-9568.2005.04311.x European Journal of Neuroscience, Vol. 22, No. 6. (September 2005), pp. 1502-1512. 2005-09-28T16:47:50-00:00 2005 European Journal of Neuroscience 0953-816X 22 6 1502 1512 Blackwell Publishing chick discounting electrophysiology reward ventral_striatum http://www.citeulike.org/user/klouie/article/493561 <i>Behav Brain Res, Vol. 55, No. 2. (30 June 1993), pp. 243-252.</i><br /><br />To analyse the functioning of the ventral striatum, the responses of more than 1,000 single neurons were recorded in a region which included the nucleus accumbens and olfactory tubercle in 5 macaque monkeys. While the monkeys performed visual discrimination and related feeding tasks, the different populations of neurons found included neurons which responded to novel visual stimuli; to reinforcement-related visual stimuli such as (for different neurons) food-related stimuli, aversive stimuli, or faces; to other visual stimuli; in relation to somatosensory stimulation and movement; or to cues which signalled the start of a task. The neurons with responses to reinforcing or novel visual stimuli may reflect the inputs to the ventral striatum from the amygdala and hippocampus, and are consistent with the hypothesis that the ventral striatum provides a route for learned reinforcing and novel visual stimuli to influence behaviour. Neuronal responses in the ventral striatum of the behaving macaque. GV Williams ET Rolls CM Leonard C Stern Behav Brain Res, Vol. 55, No. 2. (30 June 1993), pp. 243-252. 2006-02-03T17:29:05-00:00 1993 Behav Brain Res 0166-4328 55 2 243 252 monkey neurophysiology reward ventral_striatum http://www.citeulike.org/user/klouie/article/138466 <i>Exp Brain Res (8 March 2005)</i><br /><br />Rewards are often not only valued according to their physical characteristics but also relative to other available rewards. The striatum (caudate nucleus, putamen, ventral striatum including nucleus accumbens) is involved in the organization of movement and the processing of reward information. We studied the activity of single striatal neurons in macaques that were presented with different combinations of two rewards. We found in nearly half of the investigated neurons that the processing for one reward shifted, relative to the other rewards that were available in a given trial block. The relative reward processing concerned all forms of striatal activity related to reward-predicting visual stimuli, arm movements and reception of rewards. The observed changes may provide a neural basis for the known shifts in valuation of rewarding outcomes relative to known references. Relative reward processing in primate striatum. Howard Cromwell Oum Hassani Wolfram Schultz doi:10.1007/s00221-005-2223-z Exp Brain Res (8 March 2005) 2005-03-23T23:59:22-00:00 2005 Exp Brain Res 0014-4819 monkey neurophysiology reward ventral_striatum http://www.citeulike.org/user/klouie/article/156132 <i>J Neurophysiol, Vol. 89, No. 5. (May 2003), pp. 2823-2838.</i><br /><br />In behavioral science, it is well known that humans and nonhuman animals are highly sensitive to differences in reward magnitude when choosing an outcome from a set of alternatives. We know that a realm of behavioral reactions is altered when animals begin to expect different levels of reward outcome. Our present aim was to investigate how the expectation for different magnitudes of reward influences behavior-related neurophysiology in the anterior striatum. In a spatial delayed response task, different instruction pictures are presented to the monkey. Each image represents a different magnitude of juice. By reaching to the spatial location where an instruction picture was presented, animals could receive the particular liquid amount designated by the stimulus. Reliable preferences in reward choice trials and differences in anticipatory licks, performance errors, and reaction times indicated that animals differentially expected the various reward amounts predicted by the instruction cues. A total of 374 of 2,000 neurons in the anterior parts of the caudate nucleus, putamen, and ventral striatum showed five forms of task-related activation during the preparation or execution of movement and activations preceding or following the liquid drop delivery. Approximately one-half of these striatal neurons showed differing response levels dependent on the magnitude of liquid to be received. Results of a linear regression analysis showed that reward magnitude and single cell discharge rate were related in a subset of neurons by a monotonic positive or negative relationship. Overall, these data support the idea that the striatum utilizes expectancies that contain precise information concerning the predicted, forthcoming level of reward in directing general behavioral reactions. Effects of expectations for different reward magnitudes on neuronal activity in primate striatum. HC Cromwell W Schultz doi:10.1152/jn.01014.2002 J Neurophysiol, Vol. 89, No. 5. (May 2003), pp. 2823-2838. 2005-04-08T21:40:19-00:00 2003 J Neurophysiol 0022-3077 89 5 2823 2838 basal_ganglia monkey neurophysiology _pg reward ventral_striatum http://www.citeulike.org/user/klouie/article/804182 <i>Nat Neurosci, Vol. 5, No. 2. (February 2002), pp. 97-98.</i><br /><br />The mesolimbic dopaminergic system has long been known to be involved in the processing of rewarding stimuli, although recent evidence from animal research has suggested a more specific role of signaling errors in the prediction of rewards. We tested this hypothesis in humans, using functional magnetic resonance imaging (fMRI) and an operant conditioning paradigm for the discrete delivery of small quantities of fruit juice, along with a control experiment in which juice was substituted with a neutral visual stimulus. A local estimation of the activity in the ventral striatum showed a significant differentiation when the juice was withheld at the expected time of delivery; this finding was not replicated in the case of visual stimulation, providing evidence for time-locked processing of reward prediction errors in human ventral striatum. Activity in human ventral striatum locked to errors of reward prediction. G Pagnoni CF Zink PR Montague GS Berns doi:10.1038/nn802 Nat Neurosci, Vol. 5, No. 2. (February 2002), pp. 97-98. 2006-08-17T13:08:44-00:00 2002 Nat Neurosci 1097-6256 5 2 97 98 fmri human pg reward ventral_striatum http://www.citeulike.org/user/klouie/article/455012 <i>Ann N Y Acad Sci, Vol. 877 (29 June 1999), pp. 49-63.</i><br /><br />The ventral striatum, which prominently includes the nucleus accumbens (Acb), is a heterogeneous area. Within the Acb of rats, a peripherally located shell and a centrally situated core can be recognized that have different connectional, neurochemical, and functional identities. Although the Acb core resembles in many respects the dorsally adjacent caudate-putamen complex in its striatal character, the Acb shell has, in addition to striatal features, a more diverse array of neurochemical characteristics, and afferent and efferent connections. Inputs and outputs of the Acb, in particular of the shell, are inhomogeneously distributed, resulting in a mosaical arrangement of concentrations of afferent fibers and terminals and clusters of output neurons. To determine the precise relationships between the distributional patterns of various afferents (e.g., from the prefrontal cortex, the basal amygdaloid complex, the hippocampal formation, and the midline/intralaminar thalamic nuclei) and efferents to the ventral pallidum and mesencephalon, neuroanatomical anterograde and retrograde tracing experiments were carried out. The results of the double anterograde, double retrograde, and anterograde/retrograde tracing experiments indicate that various parts of the shell (dorsomedial, ventromedial, ventral, and lateral) and the core (medial and lateral) have different input-output characteristics. Furthermore, within these Acb regions, various populations of neurons can be identified, arranged in a cluster-like fashion, onto which specific sets of afferents converge and that project to particular output stations, distinct from the input-output relationships of neighboring, cluster-like neuronal populations. These results support the idea that the nucleus accumbens may consist of a collection of neuronal ensembles with different input-output relationships and, presumably, different functional characteristics. Convergence and segregation of ventral striatal inputs and outputs. HJ Groenewegen CI Wright AV Beijer P Voorn Ann N Y Acad Sci, Vol. 877 (29 June 1999), pp. 49-63. 2006-01-03T19:04:09-00:00 1999 Ann N Y Acad Sci 0077-8923 877 49 63 neuroanatomy nucleus_accumbens ventral_striatum http://www.citeulike.org/user/klouie/article/455011 <i>J Neurophysiol, Vol. 75, No. 3. (March 1996), pp. 1061-1073.</i><br /><br />1. The results of neuropsychological, neuropharmacological, and neurophysiological experiments have implicated the ventral striatum in reward-related processes. We designed a task to allow us to separate the effects of sensory, motor, and internal signals so that we could study the correlation between the activity of neurons in the ventral striatum and different motivational states. In this task, a visual stimulus was used to cue the monkeys as to their progress toward earning a reward. The monkeys performed more quickly and with fewer mistakes in the rewarded trials. After analyzing the behavioral results from three monkeys, we recorded from 143 neurons from two of the monkeys while they performed the task with either juice or cocaine reward. 2. In this task the monkey was required to release its grip on a bar when a small visual response cue changed colors from red (the wait signal) to green (the go signal). The duration of the wait signal was varied randomly. The cue became blue whenever the monkey successfully responded to the go signal within 1 s of its appearance. A reward was delivered after the monkey successfully completed one, two, or three trials. The schedules were randomly interleaved. A second visual stimulus that progressively brightened or dimmed signaled to the monkeys their progress toward earning a reward. This discriminative cue allowed the monkeys to judge the proportion of work remaining in the current ratio schedule of reinforcement. Data were collected from three monkeys while they performed this task. 3. The average reaction times became faster and error rates declined as the monkeys progressed toward completing the current schedule of reinforcement and thereby earning a reward, whereas the modal reaction time did not change. As the duration of the wait period before the go signal increased, the monkeys reacted more quickly but their error rates scarcely changed. From these results we infer that the effects of motivation and motor readiness in this task are generated by separate mechanisms rather than by a single mechanism subserving generalized arousal. 4. The activity of 138 ventral striatal neurons was sampled in two monkeys while they performed the task to earn juice reward. We saw tonic changes in activity throughout the trials, and we saw phasic activity following the reward. The activity of these neurons was markedly different during juice-rewarded trials than during correctly performed trials when no reward was forthcoming (or expected). The responses also were weakly, but significantly, related to the proximity of the reward in the schedules requiring more than one trial. 5. The monkeys worked to obtain intravenous cocaine while we recorded 62 neurons. For 57 of the neurons, we recorded activity while the monkeys worked in blocks of trials during which they self-administered cocaine after blocks during which they worked for juice. Although fewer neurons responded to cocaine than to juice reward (19 vs. 33%), this difference was not significant. The neuronal response properties to cocaine and juice rewards were independent; that is, the responses when one was the reward one failed to predict the response when the other was the reward. In addition, the neuronal activity lost most of its selectivity for rewarded trials, i.e, the activity did not distinguish nearly as well between cocaine and sham rewards as between juice and sham rewards. 6. Our results show that mechanisms by which cocaine acts do not appear to be the same as the ones activated when the monkeys were presented with an oral juice reward. This finding raises the intriguing possibility that the effects of cocaine could be reduced selectively without blocking the effects of many natural rewards. Neural signals in the monkey ventral striatum related to motivation for juice and cocaine rewards. EM Bowman TG Aigner BJ Richmond J Neurophysiol, Vol. 75, No. 3. (March 1996), pp. 1061-1073. 2006-01-03T19:02:13-00:00 1996 J Neurophysiol 0022-3077 75 3 1061 1073 cocaine electrophysiology monkey nucleus_accumbens _pg reward ventral_striatum http://www.citeulike.org/user/klouie/article/843643 <i>Prog Neurobiol, Vol. 42, No. 6. (April 1994), pp. 719-761.</i> The nucleus accumbens as a complex of functionally distinct neuronal ensembles: an integration of behavioural, electrophysiological and anatomical data. CM Pennartz HJ Groenewegen FH Lopes da Silva Prog Neurobiol, Vol. 42, No. 6. (April 1994), pp. 719-761. 2006-09-14T21:05:03-00:00 1994 Prog Neurobiol 0301-0082 42 6 719 761 neuroanatomy nucleus_accumbens review ventral_striatum http://www.citeulike.org/user/klouie/article/825559 <i>J Neurosci, Vol. 15, No. 7 Pt 1. (July 1995), pp. 4851-4867.</i><br /><br />The ventral striatum is considered an interface between limbic and motor systems. We followed the orbital and medial prefrontal circuit through the monkey basal ganglia by analyzing the projection from this cortical area to the ventral striatum and the representation of orbitofrontal cortex via the striatum, in the globus pallidus and substantia nigra. Following injections of Lucifer yellow and horse radish peroxidase into the medial ventral striatum, there is a very densely labeled distribution of cells in areas 13a and 13b, primarily in layers V and VI, and in medial prefrontal areas 32 and 25. Injections into the shell of the nucleus accumbens labeled primarily areas 25 and 32. The reaction product in the globus pallidus and the substantia nigra supports previous studies demonstrating that efferent projections from the ventral striatum are represented topographically in the ventral pallidum and nontopographically in the substantia nigra, pars compacta. Tritiated amino acid or PHA-L tracer injections into orbitofrontal cortex produce dense patches of terminal labeling along the medial edge of the caudate nucleus and the dorsal part of the nucleus accumbens. These results demonstrate that the orbital prefrontal cortex projects primarily to the medial edge of the ventral striatum and to the core of the nucleus accumbens. The arrangement of terminals in the globus pallidus and substantia nigra show two different patterns. Thus, the orbital and medial prefrontal cortex is represented in a confined region of the globus pallidus but throughout an extensive area of the dorsal substantia nigra. Terminals are extensive throughout the region of the dopaminergic neurons, suggesting that this input may influence a wide area of both the striatum and frontal cortex. The orbital and medial prefrontal circuit through the primate basal ganglia. SN Haber K Kunishio M Mizobuchi E Lynd-Balta J Neurosci, Vol. 15, No. 7 Pt 1. (July 1995), pp. 4851-4867. 2006-09-01T21:32:56-00:00 1995 J Neurosci 0270-6474 15 7 Pt 1 4851 4867 monkey neuroanatomy ofc ventral_striatum http://www.citeulike.org/user/klouie/article/483008 <i>J Neurosci, Vol. 18, No. 7. (1 April 1998), pp. 2613-2625.</i><br /><br />Single neurons in the ventral striatum of primates carry signals that are related to reward and motivation. When monkeys performed a task requiring one to three bar release trials to be completed successfully before a reward was given, they seemed more motivated as the rewarded trials approached; they responded more quickly and accurately. When the monkeys were cued as to the progress of the schedule, 89 out of 150 ventral striatal neurons responded in at least one part of the task: (1) at the onset of the visual cue, (2) near the time of bar release, and/or (3) near the time of reward delivery. When the cue signaled progress through the schedule, the neuronal activity was related to the progress through the schedule. For example, one large group of these neurons responded in the first trial of every schedule, another large group responded in trials other than the first of a schedule, and a third large group responded in the first trial of schedules longer than one. Thus, these neurons coded the state of the cue, i.e., the neurons carried the information about how the monkey was progressing through the task. The differential activity disappeared on the first trial after randomizing the relation of the cue to the schedule. Considering the anatomical loop structure that includes ventral striatum and prefrontal cortex, we suggest that the ventral striatum might be part of a circuit that supports keeping track of progress through learned behavioral sequences that, when successfully completed, lead to reward. Neuronal signals in the monkey ventral striatum related to progress through a predictable series of trials. M Shidara TG Aigner BJ Richmond J Neurosci, Vol. 18, No. 7. (1 April 1998), pp. 2613-2625. 2006-01-27T17:19:27-00:00 1998 J Neurosci 0270-6474 18 7 2613 2625 discounting electrophysiology monkey _pg ventral_striatum http://www.citeulike.org/user/klouie/article/455644 <i>J Neurosci, Vol. 12, No. 12. (December 1992), pp. 4595-4610.</i><br /><br />Projections from cortical and subcortical limbic structures to the basal ganglia are predominantly directed to the ventral striatum. The present study investigated how the expectation of external events with behavioral significance is reflected in the activity of ventral striatal neurons. A total of 420 neurons were studied in macaque monkeys performing in a delayed go-no-go task. Lights of different colors instructed the animal to do an arm-reaching movement or refrain from moving, respectively, when a trigger light was illuminated a few seconds later. Task performance was reinforced by liquid reward in both situations. A total of 60 ventral striatal neurons showed sustained increases of activity before the occurrence of individual task events. In 43 of these neurons, activations specifically preceded the delivery of reward, independent of the movement or no-movement reaction. In a series of additional tests, these activations were time locked to the subsequent reward, disappeared within a few trials when reward was omitted, and were temporally unrelated to mouth movements. Changes in the appetitive value of the reward liquid modified the magnitude of activations, suggesting a possible relationship to the hedonic properties of the expected event. Activations also occurred when reward was delivered in a predictable manner outside of any behavioral task. These data suggest that neurons in the ventral striatum are activated during states of expectation of individual environmental events that are predictable to the subject through its past experience. The prevalence of activations related to the expectation of reward suggests that ventral striatal neurons have access to central representations of reward and thereby participate in the processing of information underlying the motivational control of goal-directed behavior. Neuronal activity in monkey ventral striatum related to the expectation of reward. W Schultz P Apicella E Scarnati T Ljungberg J Neurosci, Vol. 12, No. 12. (December 1992), pp. 4595-4610. 2006-01-04T18:40:24-00:00 1992 J Neurosci 0270-6474 12 12 4595 4610 electrophysiology monkey _pg reward reward_expectation ventral_striatum http://www.citeulike.org/user/klouie/article/882737 <i>Prog Neurobiol, Vol. 14, No. 2-3. (1980), pp. 69-97.</i> From motivation to action: functional interface between the limbic system and the motor system. GJ Mogenson DL Jones CY Yim Prog Neurobiol, Vol. 14, No. 2-3. (1980), pp. 69-97. 2006-10-03T16:41:22-00:00 1980 Prog Neurobiol 0301-0082 14 2-3 69 97 review reward ventral_striatum http://www.citeulike.org/user/klouie/article/494274 <i>Neuron, Vol. 38, No. 4. (22 May 2003), pp. 625-636.</i><br /><br />A growing body of evidence implicates the ventral striatum in using information acquired through associative learning. The present study examined the activity of ventral striatal neurons in awake, behaving rats during go/no-go odor discrimination learning and reversal. Many neurons fired selectively to odor cues predictive of either appetitive (sucrose) or aversive (quinine) outcomes. Few neurons were selective when first exposed to the odors, but many acquired this differential activity as rats learned the significance of the cues. A substantial proportion of these neurons encoded the cues' learned motivational significance, and these neurons tended to reverse their firing selectivity after reversal of odor-outcome contingencies. Other neurons that became selectively activated during learning did not reverse, but instead appeared to encode specific combinations of cues and associated motor responses. The results support a role for ventral striatum in using the learned significance, both appetitive and aversive, of predictive cues to guide behavior. Neural encoding in ventral striatum during olfactory discrimination learning. B Setlow G Schoenbaum M Gallagher Neuron, Vol. 38, No. 4. (22 May 2003), pp. 625-636. 2006-02-06T17:00:03-00:00 2003 Neuron 0896-6273 38 4 625 636 aversive neurophysiology _pg rat reward ventral_striatum http://www.citeulike.org/user/klouie/article/494337 <i>Neurosci Biobehav Rev, Vol. 27, No. 8. (January 2004), pp. 765-776.</i><br /><br />The nucleus accumbens is a brain region that participates in the control of behaviors related to natural reinforcers, such as ingestion, sexual behavior, incentive and instrumental learning, and that also plays a role in addictive processes. This paper comprises a review of work from our laboratory that focuses on two main research areas: (i). the role of the nucleus accumbens in food motivation, and (ii). its putative functions in cellular plasticity underlying appetitive learning. First, work within a number of different behavioral paradigms has shown that accumbens neurochemical systems play specific and dissociable roles in different aspects of food seeking and food intake, and part of this function depends on integration with the lateral hypothalamus and amygdala. We propose that the nucleus accumbens integrates information related to cognitive, sensory, and emotional processing with hypothalamic mechanisms mediating energy balance. This system as a whole enables complex hierarchical control of adaptive ingestive behavior. Regarding the second research area, our studies examining acquisition of lever-pressing for food in rats have shown that activation of glutamate N-methyl-d-aspartate (NMDA) receptors, within broadly distributed but interconnected regions (nucleus accumbens core, posterior striatum, prefrontal cortex, basolateral and central amygdala), is critical for such learning to occur. This receptor stimulation triggers intracellular cascades that involve protein phosphorylation and new protein synthesis. It is hypothesized that activity in this distributed network (including D1 receptor activity) computes coincident events and thus enhances the probability that temporally related actions and events (e.g. lever pressing and delivery of reward) become associated. Such basic mechanisms of plasticity within this reinforcement learning network also appear to be profoundly affected in addiction. Ventral striatal control of appetitive motivation: role in ingestive behavior and reward-related learning. AE Kelley doi:10.1016/j.neubiorev.2003.11.015 Neurosci Biobehav Rev, Vol. 27, No. 8. (January 2004), pp. 765-776. 2006-02-06T19:22:39-00:00 2004 Neurosci Biobehav Rev 0149-7634 27 8 765 776 review reward ventral_striatum http://www.citeulike.org/user/klouie/article/851213 <i>Behav Cogn Neurosci Rev, Vol. 1, No. 4. (1 December 2002), pp. 281-296.</i><br /><br />The nucleus accumbens (Acb) is a crucial component of the brain reward system. This report reviews electrophysiological studies that examined Acb cell firing during goal-directed behaviors for natural reinforcers (food, water, sucrose) and drugs of abuse (cocaine, heroin, ethanol). Studies that examined the role of environmental stimuli and operant contingencies on Acb activity during behavior are also explored. Given the extensive literature that links dopamine in the Acb with drug reinforcement, experiments are considered that examined the influence of dopamine in modulating Acb cell firing during drug-seeking behaviors. Finally, because the Acb is one neural substrate of a larger brain reward circuit, the influence of afferent input (hippocampus and prefrontal cortex) on Acb cell firing during behavior is also discussed. These findings provide a unique insight into the cellular mechanisms underlying reward-related processing and goal-directed behaviors and reveal a level of functional organization in the Acb not identified by other experimental approaches. 10.1177/1534582302238338 The Nucleus Accumbens and Reward: Neurophysiological Investigations in Behaving Animals Regina Carelli doi:10.1177/1534582302238338 Behav Cogn Neurosci Rev, Vol. 1, No. 4. (1 December 2002), pp. 281-296. 2006-09-20T13:23:10-00:00 2002 Behav Cogn Neurosci Rev 1 4 281 296 nucleus_accumbens review reward ventral_striatum http://www.citeulike.org/user/klouie/article/802975 <i>J Neurosci, Vol. 26, No. 32. (9 August 2006), pp. 8368-8376.</i><br /><br />The anterior cingulate and orbital cortices and the ventral striatum process different aspects of reward evaluation, whereas the dorsolateral prefrontal cortex and the dorsal striatum are involved in cognitive function. Collectively, these areas are critical to decision making. We mapped the striatal area that receives information about reward evaluation. We also explored the extent to which terminals from reward-related cortical areas converge in the striatum with those from cognitive regions. Using three-dimensional-rendered reconstructions of corticostriatal projection fields along with two-dimensional chartings, we demonstrate the reward and cognitive territories in the primate striatum and show the convergence between these cortical inputs. The results show two labeling patterns: a focal projection field that consists of densely distributed terminal patches, and a diffuse projection consisting of clusters of fibers, extending throughout a wide area of the striatum. Together, these projection fields demonstrate a remarkably large, rostral, reward-related striatal territory that reaches into the dorsal striatum. Fibers from different reward-processing and cognitive cortical areas occupy both separate and converging territories. Furthermore, the diffuse projection may serve a separate integrative function by broadly disseminating general cortical activity. These findings show that the rostral striatum is in a unique position to mediate different aspects of incentive learning. Furthermore, areas of convergence may be particularly sensitive to dopamine modulation during decision making and habit formation. Reward-related cortical inputs define a large striatal region in primates that interface with associative cortical connections, providing a substrate for incentive-based learning. SN Haber KS Kim P Mailly R Calzavara doi:10.1523/JNEUROSCI.0271-06.2006 J Neurosci, Vol. 26, No. 32. (9 August 2006), pp. 8368-8376. 2006-08-16T21:52:20-00:00 2006 J Neurosci 1529-2401 26 32 8368 8376 monkey neuroanatomy _pg reward ventral_striatum http://www.citeulike.org/user/klouie/article/825331 <i>J Neurosci, Vol. 22, No. 23. (1 December 2002), pp. 10078-10082.</i><br /><br />Afferents from the amygdala help to define the ventral striatum and mediate goal-directed behaviors. In addition to well known inputs to the classic ventral striatum, the amygdala also projects to the caudoventral striatum and amygdalostriatal area. We examined whether the primate caudoventral striatum and amygdalostriatal area can be considered part of the "ventral" striatum based on cellular and histochemical features found in the classic rostral ventral striatum. We used several histochemical stains, including calbindin-D28k, a marker of the shell compartment, acetylcholinesterase, substance P, tyrosine hydroxylase, and Bcl-2, a marker of immature neurons, to examine this question. Our results indicate that the lateral amygdalostriatal area and caudoventral striatum are "striatal like" based on intermediate to high acetylcholinesterase and tyrosine hydroxylase levels. The lateral amygdalostriatal area is chemically similar to the shell, whereas the caudoventral striatum more closely resembles the striatum outside the shell. In contrast, the medial amygdalostriatal area is more related to the central amygdaloid nucleus than to the striatum. Bcl-2 immunoreactivity is associated with granular islands and medium-sized cells in the vicinity of the ventral striatum both rostrally and caudally. Together, the caudal ventral striatum has a histochemical and cellular organization similar to that of the rostral ventral striatum, consistent with their common innervation by the amygdala and other ventral structures. In addition, Bcl-2 is expressed in and near both poles of the ventral striatum, suggesting that these areas maintain a heightened capacity for growth and plasticity compared with other striatal sectors. Defining the caudal ventral striatum in primates: cellular and histochemical features. JL Fudge SN Haber J Neurosci, Vol. 22, No. 23. (1 December 2002), pp. 10078-10082. 2006-09-01T14:52:37-00:00 2002 J Neurosci 1529-2401 22 23 10078 10082 monkey neuroanatomy ventral_striatum http://www.citeulike.org/user/klouie/article/87212 <i>Current Opinion in Neurobiology, Vol. 14, No. 6. (December 2004), pp. 763-768.</i><br /><br />An understanding of the neurobiological basis of drug addiction requires examination of real-time (subsecond) cellular and chemical responses in the brain reward system during drug-seeking and drug-taking behavior. Electrophysiological and electrochemical studies in the rodent nucleus accumbens have examined changes in cell firing and rapid dopamine signaling during crucial periods of behavioral responding for drugs, and show the associative nature of those signals. These findings are considered with respect to the functional microcircuitry in the nucleus accumbens that underlies goal-directed behavior and the role of this circuit in drug addiction. Functional microcircuitry in the accumbens underlying drug addiction: insights from real-time signaling during behavior Regina Carelli Mark Wightman doi:10.1016/j.conb.2004.10.001 Current Opinion in Neurobiology, Vol. 14, No. 6. (December 2004), pp. 763-768. 2005-02-05T04:04:19-00:00 2004 Current Opinion in Neurobiology 14 6 763 768 cyclic_voltammetry nucleus_accumbens rat review reward ventral_striatum