This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Damage to medial temporal lobe structures in monkeys impairs performance on a task of visual recognition memory, the Visual Preferential Looking Task (VPLT). The objective of this project is to identify the neuronal mechanisms that support memory performance on the VPLT in awake, behaving monkeys. In the past year, we have completed data analyses that demonstrate the existence of theta-band oscillations in the primate hippocampus, and that the phase of these oscillations is reset by eye-movements during visual exploration. In addition, our recent data show that theta-band phase modulates the power of gamma-band activity and a specific theta-band phase is related to successful memory encoding. Together, these data suggests that phase resetting of the theta-band oscillation to an 'ideal phase'upon fixation onset may align hippocampal activity to an optimal state with respect to gamma-band synchronization and memory formation. A manuscript describing these data has been submitted and is currently under review, and a peer-reviewed review article describing the role of synchronous activity in memory formation was published in Current Opinion in Neurobiology. In addition, we have completed recording and preliminary analyses of firing rate changes, gamma-band modulation and theta-band modulation in the entorhinal cortex as monkeys perform the VPLT. These results were presented at the 2010 Society for Neuroscience meeting. In the past year, we have also identified face-specific neural activity in the monkey hippocampus that appears to be related to enhanced memory for face stimuli. These preliminary results were also presented at the 2010 Society for Neuroscience meeting.
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