Plasticity of Associative Memory Cells

  • Jin-Hui Wang


Neuronal plasticity has been observed in aspects of synapse transmission and neuron encoding capability, which has been thought to be relevant to learning and memory. The joint acquisitions, the integrative storages, and the reciprocal retrievals of associated signals are most commonly occurring in the life. Synaptic plasticity in a neural pathway may not reflect to associative processes in memory, though the plasticity of the neuronal encoding may be involved in the capability of signal integration in the cell body of neurons. Synaptic and neuronal plasticity is better to be studied in memory cells, which may be relevant to their recruitment and refinement. With the mouse model of associative learning by pairing cross-modal sensory signals, memory cells that encode the associated sensory signals have been functionally and morphologically identified in sensory cortices, prefrontal cortex, hippocampus, and motor cortex. In these associative memory cells, the excitatory synaptic transmission is upregulated, the inhibitory synaptic transmission is downregulated, the glutamatergic neuronal excitability is upregulated, and the GABAergic neuronal excitability is downregulated. These alternations may facilitate to shift the balance between excitation and inhibition toward more excitatory state in neural networks, in order to strengthen the recruitment of more associative memory cells through their mutual synapse innervations based on their coactivation. To prevent over-excitation at associative memory cells in the engram circuit, there are enhanced mutual innervations between glutamatergic and GABAergic associative memory cells. Moreover, there are functional conversions from silent synapse pathways to be functional or vice versa, as well as homosynaptic versus heterosynaptic plasticity in associative memory cells. These enriched forms of synaptic plasticity may be relevant to the complicated patterns of memory formation and cognitive events. In addition, the functional fluctuation of neuronal and synaptic plasticity in memory output cells may work for the memory formation, extinction, and reemergence.


Activity-dependent plasticity Associative memory cells Glutamate and γ-aminobutyric acid 


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Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Jin-Hui Wang
    • 1
  1. 1.University of Chinese Academy of SciencesBeijingChina

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