MECHANISMS OF INHIBITION IN CAT VISUAL-CORTEX
MECHANISMS OF INHIBITION IN CAT VISUAL-CORTEX
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DOI：
10.1113/jphysiol.1991.sp018731
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发表时间：
1991-08-01
影响因子：
5.5
通讯作者：
WHITTERIDGE, D
中科院分区：
文献类型：
--
作者：
BERMAN, NJ;DOUGLAS, RJ;WHITTERIDGE, D
1. 用细胞外和细胞内记录法研究了猫初级视皮层2-6层神经元。 目的是识别抑制事件，并确定它们是否与神经元输入电导的小或大（分流）变化有关。 视觉刺激的简单感受野的子字段产生去极化或超极化电位，分别与增加或减少放电率。 超极化电位很小，小于或等于5 mV，在相同的神经元中，短暂的电刺激皮层传入神经产生了一个特征性的序列，即短暂的去极化，随后是持续时间较长（200-400 ms）的超极化. 在对固定闪光棒的反应期间，突触激活使神经元的输入电导增加约5- 20%。 通过电刺激神经元，获得了类似幅度的电导变化。 用非最佳方向或运动方向刺激神经元，其输入电导几乎没有变化. 这些数据表明，虽然视觉或电诱导的抑制可以很容易地证明在视觉皮层，抑制是不相关的大持续的电导变化。 因此，分流或倍增抑制机制不是抑制的主要机制。
1. Neurones from layers 2-6 of the cat primary visual cortex were studied using extracellular and intracellular recordings made in vivo. The aim was to identify inhibitory events and determine whether they were associated with small or large (shunting) changes in the input conductance of the neurones.2. Visual stimulation of subfields of simple receptive fields produced depolarizing or hyperpolarizing potentials that were associated with increased or decreased firing rates respectively. Hyperpolarizing potentials were small, 5 mV or less. In the same neurones, brief electrical stimulation of cortical afferents produced a characteristic sequence of a brief depolarization followed by a long-lasting (200-400 ms) hyperpolarization.3. During the response to a stationary flashed bar, the synaptic activation increased the input conductance of the neurone by about 5-20%. Conductance changes of similar magnitude were obtained by electrically stimulating the neurone. Neurones stimulated with non-optimal orientations or directions of motion showed little change in input conductance.4. These data indicate that while visually or electrically induced inhibition can be readily demonstrated in visual cortex, the inhibition is not associated with large sustained conductance changes. Thus a shunting or multiplicative inhibitory mechanism is not the principal mechanism of inhibition.