CA3 NMDA receptors are required for the rapid formation of a salient contextual representation.
The acquisition of Pavlovian fear learning engages the hippocampus when the conditioned stimuli are multimodal or temporally isolated from the unconditioned stimuli. By subjecting CA3-NR1 KO mice to conditioning protocols that incorporate time-dependent components, we found that the loss of plasticity at recurrent CA3 synapses resulted in a deficits in contextual conditioning specifically when the exposure to the context was brief or when the unconditioned stimulus was signaled with a competing, predictive unimodal stimulus. Our results suggest CA3 contributes both speed and salience to contextual processing and support the theory of competition between multimodal and unimodal conditioned stimuli for associative learning.
McHugh
Thomas J
TJ
The RIKEN-MIT Center for Neural Circuit Genetics, Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. tjmchugh@brain.riken.jp
Tonegawa
Susumu
S
D000818:Animals; D056654:CA3 Region, Hippocampal / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology*; D004597:Electroshock; D005106:Exploratory Behavior / Q000502:physiology; D005239:Fear; D046352:Freezing Reaction, Cataleptic / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*; D013997:Time Factors
C409466:NR1 NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate