Six different roles for crossover inhibition in the retina: correcting the nonlinearities of synaptic transmission.
Six different roles for crossover inhibition in the retina: correcting the nonlinearities of synaptic transmission.
复制标题
视网膜交叉抑制的六种不同作用：纠正突触传递的非线性。
DOI：
10.1017/s0952523810000076
复制
发表时间：
2010-03
影响因子：
1.9
通讯作者：
Werblin, Frank S.
中科院分区：
文献类型：
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作者：
Werblin, Frank S.
早期的视网膜研究将神经节细胞的行为分为线性或非线性，并以猫的X型和Y型神经节细胞为代表进行整流。非线性行为在很大程度上是突触传递中固有的整流非线性的结果。这些非线性信号是视网膜处理中许多特殊功能的基础，包括运动检测、运动中的运动和局部边缘检测。但是，线性行为也需要一些视觉处理任务。对于这些任务，固有的非线性信号通过“交叉抑制”被“线性化”。线性化利用非线性ON抑制与非线性OFF激励相加或ON激励与OFF抑制相加的电路，以产生更线性的突触后电压响应。交叉抑制现在已经在大多数双极细胞、无长突细胞和神经节细胞中测量到。功能交叉抑制增强边缘检测，允许神经节细胞识别亮度中性模式与他们的感受野，允许神经节细胞区分对比度亮度，并保持一个更恒定的电导在光响应。在某些情况下，交叉将视锥驱动的OFF神经节细胞的操作范围扩展到暗视水平。交叉抑制也被发现在外侧膝状体核和V1的神经元。
Early retinal studies categorized ganglion cell behavior as either linear or nonlinear and rectifying as represented by the familiar X- and Y-type ganglion cells in cat. Nonlinear behavior is in large part a consequence of the rectifying nonlinearities inherent in synaptic transmission. These nonlinear signals underlie many special functions in retinal processing, including motion detection, motion in motion, and local edge detection. But linear behavior is also required for some visual processing tasks. For these tasks, the inherently nonlinear signals are “linearized” by “crossover inhibition.” Linearization utilizes a circuitry whereby nonlinear ON inhibition adds with nonlinear OFF excitation or ON excitation adds with OFF inhibition to generate a more linear postsynaptic voltage response. Crossover inhibition has now been measured in most bipolar, amacrine, and ganglion cells. Functionally crossover inhibition enhances edge detection, allows ganglion cells to recognize luminance-neutral patterns with their receptive fields, permits ganglion cells to distinguish contrast from luminance, and maintains a more constant conductance during the light response. In some cases, crossover extends the operating range of cone-driven OFF ganglion cells into the scotopic levels. Crossover inhibition is also found in neurons of the lateral geniculate nucleus and V1.