Memory is crucial to identity and survival, and the hippocampus is required for normal memory. The causal relationship between hippocampal cell activity and learning and memory performance, however, remains unknown because few experiments record neuronal firing while memory demands are varied and other aspects of behavior are held constant.
Aim 1. To identify learning-dependent changes in neuronal encoding by recording groups of hippocampal neurons while rats perform a task that requires the hippocampus. Successful newlearning that requires the hippocampus should require the formation of new and persistent firing patterns by hippocampal neurons. Rats will be trained in a + maze task that can be solved by either hippocampus-dependent or independent strategies. Groups of hippocampal cells will be recorded in rats that behave identically but differ in learning ability, memory strategy, and hippocampal function. Probes will test the strategies used by each rat, and unit activity will be compared in normal place and response learners, and rats with fornix or caudate lesions.
Aim 2. To test the generality of the results in Aim 1, neuronal activity will be recorded in rats trained in a distinct type of learning, the social transmission of food preference. A subset of dynamic neuronal responses may be required for all types of hippocampus-dependent learning, independent of behavioral expression, type of motivation, and specific content of learning. Hippocampal neurons in normal rats should develop persistent olfactory associations between the arbitrarily selected novel food odors and the odor of carbon disulfide, the signal of food safety.
Aim 3. To test if temporal relationships among spike trains encode memory by comparing real-time ensemble activity in the hippocampus. Significant memory information may be encoded by the temporal relationships among neurons action potentials. The temporal dynamics of spiking within ensembles recorded during identical behaviors but different memoryloads will be assessed using published and a new method. The analysis will begin by comparing spike records as rats traverse the start arm of a + maze during right and left turns.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH065658-03
Application #
6721344
Study Section
Integrative, Functional and Cognitive Neuroscience 8 (IFCN)
Program Officer
Anderson, Kathleen C
Project Start
2002-04-15
Project End
2007-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
3
Fiscal Year
2004
Total Cost
$339,000
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Neurosciences
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Riceberg, Justin S; Shapiro, Matthew L (2017) Orbitofrontal Cortex Signals Expected Outcomes with Predictive Codes When Stable Contingencies Promote the Integration of Reward History. J Neurosci 37:2010-2021
Seip-Cammack, Katharine M; Young, James J; Young, Megan E et al. (2017) Partial lesion of the nigrostriatal dopamine pathway in rats impairs egocentric learning but not spatial learning or behavioral flexibility. Behav Neurosci 131:135-42
Guise, Kevin G; Shapiro, Matthew L (2017) Medial Prefrontal Cortex Reduces Memory Interference by Modifying Hippocampal Encoding. Neuron 94:183-192.e8
Shapiro, Matthew (2015) A limited positioning system for memory. Hippocampus 25:690-6
Christoffel, Daniel J; Golden, Sam A; Walsh, Jessica J et al. (2015) Excitatory transmission at thalamo-striatal synapses mediates susceptibility to social stress. Nat Neurosci 18:962-4
Tavares, Rita Morais; Mendelsohn, Avi; Grossman, Yael et al. (2015) A Map for Social Navigation in the Human Brain. Neuron 87:231-43
Seip-Cammack, Katharine M; Shapiro, Matthew L (2014) Behavioral flexibility and response selection are impaired after limited exposure to oxycodone. Learn Mem 21:686-95
Shapiro, Matthew (2013) Spatial navigation: head direction cells are anchored by gravity. Curr Biol 23:R841-3
Riceberg, Justin S; Shapiro, Matthew L (2012) Reward stability determines the contribution of orbitofrontal cortex to adaptive behavior. J Neurosci 32:16402-9
Bahar, Amir S; Shapiro, Matthew L (2012) Remembering to learn: independent place and journey coding mechanisms contribute to memory transfer. J Neurosci 32:2191-203

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