Spatial and Temporal Selectivity of Hippocampal CA3 and Its Contribution to Sequence Disambiguation

Many episodes are acquired in the hippocampus. An episode is expressed by a sequence of elements that are perceived in an event. Episodes are associated each other by events that contain information shared among the episodes. Sequences must be recalled individually, even if the sequences are overlapped at some representations. Therefore, sequence disambiguation is an essential function to dissociate overlapped sequences. In this study, we especially focus on the location-dependencies of the STDP effects on synaptic summation and the expression of AMPA receptor. We firstly show that the hippocampal CA3 is divided into two regions in which one region has spatial selectivity and the other has temporal selectivity. Moreover, we confirm that the divided CA3 could generate a code for sequence disambiguation in computer simulations. Consequently, we suggest that the CA3 can be divided into two regions characterized by their selectivity, and the divided CA3 contributes to sequence disambiguation.

[1]  Eugene M. Izhikevich,et al.  Dynamical Systems in Neuroscience: The Geometry of Excitability and Bursting , 2006 .

[2]  Nelson Spruston,et al.  Distance-Dependent Differences in Synapse Number and AMPA Receptor Expression in Hippocampal CA1 Pyramidal Neurons , 2006, Neuron.

[3]  D. Amaral,et al.  Organization of intrahippocampal projections originating from CA3 pyramidal cells in the rat , 1990, The Journal of comparative neurology.

[4]  R. Nicoll,et al.  Analysis of excitatory synaptic action in pyramidal cells using whole‐cell recording from rat hippocampal slices. , 1990, The Journal of physiology.

[5]  E T Rolls,et al.  Computational constraints suggest the need for two distinct input systems to the hippocampal CA3 network , 1992, Hippocampus.

[6]  Mu-ming Poo,et al.  Coincidence Detection of Synaptic Inputs Is Facilitated at the Distal Dendrites after Long-Term Potentiation Induction , 2006, The Journal of Neuroscience.

[7]  Shun Ishizaki,et al.  Autoassociative and heteroassociative hippocampal CA3 model based on location dependencies derived from anatomical and physiological findings , 2007 .

[8]  Eugene M. Izhikevich,et al.  Relating STDP to BCM , 2003, Neural Computation.

[9]  Shun Ishizaki,et al.  Sequence Disambiguation by Functionally Divided Hippocampal CA3 Model , 2006, ICONIP.

[10]  Takeshi Aihara,et al.  Spatial analysis of spike‐timing‐dependent LTP and LTD in the CA1 area of hippocampal slices using optical imaging , 2005, Hippocampus.

[11]  D. Amaral,et al.  A quantitative analysis of the dendritic organization of pyramidal cells in the rat hippocampus , 1995, The Journal of comparative neurology.

[12]  H. Eichenbaum.  Hippocampus Cognitive Processes and Neural Representations that Underlie Declarative Memory , 2004, Neuron.