Suppression of synaptic transmission may allow combination of associative feedback and self-organizing feedforward connections in the neocortex
Suppression of synaptic transmission may allow combination of associative feedback and self-organizing feedforward connections in the neocortex
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DOI：
10.1016/0166-4328(96)00010-1
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发表时间：
1996-09-01
影响因子：
2.7
通讯作者：
Cekic, M
中科院分区：
文献类型：
--
作者：
Hasselmo, ME;Cekic, M
学习过程中突触传递的选择性抑制被认为是将反馈突触的联想记忆功能与新皮层结构中前馈突触的自组织相结合的生理机制。一个计算模型演示了如何选择性抑制反馈传输允许这种突触功能的组合。在学习过程中，感官刺激和所需的反应同时作为网络的输入。前馈连接形成输入的自组织表示，而抑制反馈连接学习前馈连接的转置。在回忆期间，传输的抑制被移除，输入激活自组织表示，并且活动进入问题的习得解决方案。该计算模型可用于学习不可线性分离的问题，包括负模式任务（XOR问题）。在大鼠躯体感觉皮层的脑切片制备物中的实验测试了自组织和联想记忆功能的组合是否可以通过对反馈与前馈突触的选择性胆碱能抑制来提供。胆碱能激动剂卡巴胆碱选择性地抑制由I层刺激引起的突触电位（其中包含高百分比的反馈突触），而对由IV层刺激引起的突触电位没有影响（具有高百分比的传入和前馈突触）。
Selective suppression of synaptic transmission during learning is proposed as a physiological mechanism for combining associative memory function at feedback synapses with self-organization of feedforward synapses in neocortical structures. A computational model demonstrates how selective suppression of feedback transmission allows this combination of synaptic function. During learning, sensory stimuli and the desired response are simultaneously presented as input to the network. Feedforward connections form self-organized representations of input, while suppressed feedback connections learn the transpose of the feedforward connectivity. During recall, suppression of transmission is removed, input activates the self-organized representation, and activity settles into a learned solution to the problem. This computational model can be used for learning of problems which are not linearly separable, including the negative patterning task (the XOR problem). Experiments in brain slice preparations of the rat somatosensory cortex tested whether the combination of self-organization and associative memory function could be provided by cholinergic suppression selective for feedback versus feedforward synapses. The cholinergic agonist carbachol selectively suppressed synaptic potentials elicited by stimulation of layer I (which contains a high percentage of feedback synapses), while having no effect on synaptic potentials elicited by stimulation of layer IV (with a high percentage of afferent and feedforward synapses).