Thu, 21 Aug 2008 14:01:29 BST CiteULike: nelmor's binding http://www.citeulike.org/user/nelmor/tag/binding CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/nelmor/article/1604222 <i>PNAS (28 August 2007), 0701826104.</i><br /><br />Edited by Fred H. Gage, The Salk Institute for Biological Sciences, San Diego, CA, and approved July 20, 2007 (received for review February 27, 2007)The hippocampal formation is believed to be critical for the encoding, consolidation, and retrieval of episodic memories. Yet, how these processes are supported by the anatomically diverse hippocampal networks is still unknown. To examine this issue, we tested rats in a hippocampus-dependent delayed spatial alternation task on a modified T maze while simultaneously recording local field potentials from dendritic and somatic layers of the dentate gyrus, CA3, and CA1 regions by using high-density, 96-site silicon probes. Both the power and coherence of gamma oscillations exhibited layer-specific changes during task performance. Peak increases in the gamma power and coherence were found in the CA3CA1 interface on the maze segment approaching the T junction, independent of motor aspects of task performance. These results show that hippocampal networks can be dynamically coupled by gamma oscillations according to specific behavioral demands. Based on these findings, we propose that gamma oscillations may serve as a physiological mechanism by which CA3 output can coordinate CA1 activity to support retrieval of hippocampus-dependent memories. 10.1073/pnas.0701826104 Gamma oscillations dynamically couple hippocampal CA3 and CA1 regions during memory task performance Sean Montgomery Gyorgy Buzsaki doi:10.1073/pnas.0701826104 PNAS (28 August 2007), 0701826104. 2007-08-29T08:22:58-00:00 2007 PNAS 0701826104 binding ca1 ca3 gamma hippocampus oscillations synchronization http://www.citeulike.org/user/nelmor/article/1391619 <i>Science, Vol. 316, No. 5831. (15 June 2007), pp. 1609-1612.</i><br /><br />Brain processing depends on the interactions between neuronal groups. Those interactions are governed by the pattern of anatomical connections and by yet unknown mechanisms that modulate the effective strength of a given connection. We found that the mutual influence among neuronal groups depends on the phase relation between rhythmic activities within the groups. Phase relations supporting interactions between the groups preceded those interactions by a few milliseconds, consistent with a mechanistic role. These effects were specific in time, frequency, and space, and we therefore propose that the pattern of synchronization flexibly determines the pattern of neuronal interactions. 10.1126/science.1139597 Modulation of Neuronal Interactions Through Neuronal Synchronization Thilo Womelsdorf Jan-Mathijs Schoffelen Robert Oostenveld Wolf Singer Robert Desimone Andreas Engel Pascal Fries doi:10.1126/science.1139597 Science, Vol. 316, No. 5831. (15 June 2007), pp. 1609-1612. 2007-06-15T08:56:16-00:00 2007 Science 316 5831 1609 1612 binding oscillations synchronization