The Journal of Neuroscience, January 7, 2009, 29(1):131-139; doi:10.1523/JNEUROSCI.2998-08.2009
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Behavioral/Systems/Cognitive
Distinct Memory Signatures in the Hippocampus: Intentional States Distinguish Match and Mismatch Enhancement Signals
Katherine Duncan,1
Clayton Curtis,1,2 and
Lila Davachi1,2
1Department of Psychology and 2Center for Neural Science, New York University, New York, New York 10003
Correspondence should be addressed to Dr. Lila Davachi, Department of Psychology, New York University, 6 Washington Place, Room 866B, New York, NY 10003. Email: lila.davachi{at}nyu.edu
Incoming events that match or mismatch stored representations are thought to influence the ability of the hippocampus to switch between memory encoding and retrieval modes. Electrophysiological work has dissociated match and mismatch signals in the monkey perirhinal cortex, where match signals were selective for matches to goal states, whereas mismatch signals were not modulated by intention (Miller and Desimone, 1994). To investigate whether the theoretically important relational match and mismatch signals in the hippocampus are modulated by goal states, we fully crossed whether a probe stimulus relationally matched or mismatched a previously perceived image or goal state. Subjects performed two working memory tasks in which they either responded "yes" to probes that were identical to the previous sample scene or, after performing a relational manipulation of the scene, responded "yes" only to a probe that was identical to this perceptually novel image. Using functional magnetic resonance imaging, we found evidence for relational match enhancements bilaterally in the hippocampus that were selective for matches between the probe stimulus and goal state, but were not modulated by whether that goal was perceptually novel. Moreover, we found evidence for a complementary hippocampal mismatch enhancement that was triggered by stimuli containing salient perceptual manipulations. Our results provided evidence for parallel memory signatures in the hippocampus: a controlled match signal that can detect matches to internally generated goal states and an automatic mismatch signal that can identify unpredicted perceptual novelty.
Key words: hippocampus; medial temporal lobes; match enhancement; mismatch enhancement; goal states; relational memory
Received June 29, 2008;
revised Oct. 27, 2008;
accepted Oct. 29, 2008.
Correspondence should be addressed to Dr. Lila Davachi, Department of Psychology, New York University, 6 Washington Place, Room 866B, New York, NY 10003. Email: lila.davachi{at}nyu.edu
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R. K. Olsen, E. A. Nichols, J. Chen, J. F. Hunt, G. H. Glover, J. D. E. Gabrieli, and A. D. Wagner
Performance-Related Sustained and Anticipatory Activity in Human Medial Temporal Lobe during Delayed Match-to-Sample
J. Neurosci.,
September 23, 2009;
29(38):
11880 - 11890.
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