Stimulus selection via differential response latencies in visual cortical area V4
Stimulus selection via differential response latencies in visual cortical area V4
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DOI：
10.1016/j.neulet.2008.02.036
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发表时间：
2008-04-25
影响因子：
2.5
通讯作者：
Gawne, Timothy J.
中科院分区：
文献类型：
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作者：
Gawne, Timothy J.
大脑皮层的任何给定区域都有多个输入，这些输入如何组合或选择是大脑皮质功能的关键组成部分。在脑片或其他简化准备中的实验表明，兴奋性输入到皮质会产生延迟的前馈抑制，这表明输入的相对时间在几十毫秒的尺度上对皮质操作至关重要。其他机制，如突触抑制和反馈抑制，也被证明对这一时间尺度产生了强烈的影响。因此，输入的相对时序应该是决定给定皮质区域如何选择或组合其输入的基础。一只恒河猴(Macaca Mulatta)被训练成专注于一点光线来获得果汁奖励。用标准微电极技术记录视觉皮层V4区分离的单个单位。两个视觉刺激被放置在这样的位置，每个单独引起强烈的反应。刺激分别呈现和组合呈现，其对比度和相对起效时间各不相同。一般来说，每个神经元对两个刺激的反应被锁定在对产生最短潜伏期的单一刺激的反应上。一个部分的例外是，对低对比度刺激的反应通常不太有效地抑制对高对比度刺激的较晚反应。在视觉皮层神经元的感受野中呈现两个刺激，被认为是一个模型系统，用于研究输入的相对时序的变化如何影响完整系统中的皮质功能。(C)2008爱思唯尔爱尔兰有限公司。保留所有权利。
Any given region of the cerebral cortex gets multiple inputs, and how these inputs are combined or selected is a key component of cortical function. Experiments in brain slices or other reduced preparations have shown that excitatory inputs to cortex produce a delayed feed-forward inhibition, which suggests that the relative timing of inputs at the scale of tens of milliseconds is crucial to cortical operation. Other mechanisms, such as synaptic depression and feedback inhibition, have also been shown to produce strong effects on this timescale. Thus, the relative timing of inputs should be fundamental in determining how a given region of cortex selects or combines its inputs. A rhesus monkey (Macaca mulatta) was trained to fixate on a spot of light for juice reward. Isolated single units in visual cortical area V4 were recorded using standard microelectrode techniques. Two visual stimuli were positioned such that each alone elicited a strong response. The stimuli were presented both separately and in combination, and their contrast and relative onset timing were varied. In general, the response of each neuron to two stimuli was locked to the response to that single stimulus that produced the shortest latency. A partial exception was that the responses to low-contrast stimuli were often less effective at suppressing later-arriving responses to high-contrast stimuli. The presentation of two stimuli in the receptive field of a visual cortical neuron is proposed as a model system for how changes in the relative timing of inputs affect cortical function in the intact system. (c) 2008 Elsevier Ireland Ltd. All rights reserved.