CiteULike: sekulerlab's intention

Neural substrates for action understanding at different description levels in the human brain.

V Lestou — 2008-02-27T18:25:08-00:00

J Cogn Neurosci, Vol. 20, No. 2. (February 2008), pp. 324-341.

Understanding complex movements and abstract action goals is an important skill for our social interactions. Successful social interactions entail understanding of actions at different levels of action description, ranging from detailed movement trajectories that support learning of complex motor skills through imitation to distinct features of actions that allow us to discriminate between action goals and different action styles. Previous studies have implicated premotor, parietal, and superior temporal areas in action understanding. However, the role of these different cortical areas in action understanding at different levels of action description remains largely unknown. We addressed this question using advanced animation and stimulus generation techniques in combination with sensitive functional magnetic resonance imaging adaptation or repetition suppression methods. We tested the neural sensitivity of fronto-parietal and visual areas to differences in the kinematics and goals of actions using kinematic morphs of arm movements. Our findings provide novel evidence for differential involvement of ventral premotor, parietal, and temporal regions in action understanding. We show that the ventral premotor cortex encodes the physical similarity between movement trajectories and action goals that are important for exact copying of actions and the acquisition of complex motor skills. In contrast, whereas parietal regions and the superior temporal sulcus process the perceptual similarity between movements and may support the perception and imitation of abstract action goals and movement styles. Thus, our findings propose that fronto-parietal and visual areas involved in action understanding mediate a cascade of visual-motor processes at different levels of action description from exact movement copies to abstract action goals achieved with different movement styles.

Attention, intention and domain-specific processing

Matthew Finkbeiner — 2008-02-01T17:36:32-00:00

Trends in Cognitive Sciences, Vol. 12, No. 2. (February 2008), pp. 59-64.

Many researchers use subliminal priming to investigate domain-specific processing mechanisms, which have classically been defined in terms of their autonomy from other cognitive systems. Surprisingly, recent research has demonstrated that nonconsciously elicited cognitive processes are not independent of attention. By extension, these findings have been used to call into question the autonomy of domain-specific processing mechanisms. By contrast, we argue that the demonstrated modulation of nonconscious cognitive processes by attention occurs at a predomain-specific stage of processing. Thus, although we agree that attention might be a prerequisite of nonconscious processes, we suggest that there is no reason to think that higher-level cognitive systems directly modulate domain-specific processes.

Reading Hidden Intentions in the Human Brain

John-Dylan Haynes — 2007-03-21T22:27:32-00:00

Current Biology, Vol. 17, No. 4. (20 February 2007), pp. 323-328.

Summary When humans are engaged in goal-related processing, activity in prefrontal cortex is increased and . However, it has remained unclear whether this prefrontal activity encodes a subject's current intention . Instead, increased levels of activity could reflect preparation of motor responses and , holding in mind a set of potential choices , tracking the memory of previous responses , or general processes related to establishing a new task set. Here we study subjects who freely decided which of two tasks to perform and covertly held onto an intention during a variable delay. Only after this delay did they perform the chosen task and indicate which task they had prepared. We demonstrate that during the delay, it is possible to decode from activity in medial and lateral regions of prefrontal cortex which of two tasks the subjects were covertly intending to perform. This suggests that covert goals can be represented by distributed patterns of activity in the prefrontal cortex, thereby providing a potential neural substrate for prospective memory , and . During task execution, most information could be decoded from a more posterior region of prefrontal cortex, suggesting that different brain regions encode goals during task preparation and task execution. Decoding of intentions was most robust from the medial prefrontal cortex, which is consistent with a specific role of this region when subjects reflect on their own mental states.

Manipulating the experienced onset of intention after action execution.

HC Lau — 2007-01-24T16:35:48-00:00

J Cogn Neurosci, Vol. 19, No. 1. (January 2007), pp. 81-90.

Using transcranial magnetic stimulation (TMS), we have tested the time needed for the perceived onset of spontaneous motor intention to be fully determined. We found that TMS applied over the presupplementary motor area after the execution of a simple spontaneous action shifted the perceived onset of the motor intention backward in time, and shifted the perceived time of action execution forward in time. The size of the effect was similar regardless of whether TMS was applied immediately after the action or 200 msec after. The results of three control studies suggest that this effect is time-limited, specific to modality, and also specific to the anatomical site of stimulation. We conclude that the perceived onset of intention depends, at least in part, on neural activity that takes place after the execution of action. A model, which is based on the mechanism of cue integration under the presence of noise, is offered to explain the results. The implications for the conscious control of spontaneous actions are discussed.