Affiliation:
1. Institute and Key Laboratory of Brain Functional Genomics of Chinese Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, China
Abstract
Abstract
Clarifying learning-induced synaptic plasticity in hippocampal circuits is critical for understanding hippocampal mechanisms of memory acquisition and storage. Many in vitro studies have demonstrated learning-associated plasticity at hippocampal synapses. However, as a neural basis of memory encoding, the nature of synaptic plasticity underlying hippocampal neuronal responses to memorized stimulation remains elusive. Using in vivo whole-cell recording in anaesthetized adult rats and mice, we investigated synaptic activity of hippocampal CA1 pyramidal cells (PCs) in response to a flash of visual stimulation as the conditioned stimulus (CS) in associative fear conditioning. We found that shortly (<3 days) after conditioning, excitatory synaptic responses and spiking responses to the flash CS emerged in a large number (~70%) of CA1 PCs, a neuronal population previously unresponsive to the flash before conditioning. The learning-induced CA1 excitatory responsiveness was further indicated to result from postsynaptic unsilencing at flash-associated silent synapses, with NMDA receptor-gated responses we recently reported in naive animals. Our findings suggest that associative fear learning can induce excitatory responsiveness to the memorized CS in a large population of CA1 neurons, via a process of postsynaptic unsilencing at CA1 silent synapses, which may be critical for hippocampal acquisition and storage of associative memory.
Funder
National Natural Science Foundation of China
Key Project of Shanghai Science and Technology Commission
Publisher
Oxford University Press (OUP)
Subject
Cellular and Molecular Neuroscience,Cognitive Neuroscience
Cited by
8 articles.
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