ON THE ORGANIZATION OF RECEPTIVE FIELDS OF ORIENTATION-SELECTIVE UNITS RECORDED IN THE FISH TECTUM
ON THE ORGANIZATION OF RECEPTIVE FIELDS OF ORIENTATION-SELECTIVE UNITS RECORDED IN THE FISH TECTUM
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DOI：
10.1142/s0219635209002174
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发表时间：
2009-09-01
影响因子：
1.8
通讯作者：
Maximov, Vadim
中科院分区：
文献类型：
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作者：
Damjanovic, Ilija;Maximova, Elena;Maximov, Vadim
来自两种类型的视网膜起源的方向选择单元（水平线检测器和垂直线检测器）的反应是从固定化鲤鱼银鲫顶盖视网膜接受层内侧下层的轴突末端记录到细胞外的。评估了方向选择单元感受野的兴奋性和抑制性影响。通过移动边缘和闪烁窄明暗条纹来估计感受野响应部分的位置、大小和形式。结果表明，鱼类的方向选择单位的特点是响应感受野较小，平均宽度为 4.8 +/- 1.6 度 (n = 176)。不同类型方向选择单元的比较表明，垂直线探测器的响应感受野明显比水平线探测器宽（13%）。通过亮边缘和暗边缘评估的响应感受野的大小之间也发现了统计学上的显着差异。光边缘（ON 响应）估计的平均响应感受野宽度比暗边缘（OFF 响应）估计的平均响应感受野宽度更宽。基于两种实验方法评估了方向选择单元感受野的抑制。从实验结果中得出了信号在感受野上并不是线性求和的证据。记录在方向选择单元的感受野中的抑制影响总是在响应性感受野区域内发起并向外围传播。研究结果表明，感受野不能被定义为由响应生成的线性机制驱动的均匀感觉区。鱼类的方向选择单元的感受野似乎由对适当方向的刺激敏感的亚单元组成。
Responses from two types of orientation-selective units of retinal origin (detectors of horizontal lines and detectors of vertical lines) were recorded extracellularly from their axon terminals in the medial sublamina of tectal retinorecipient layer of immobilized cyprinid fish Carassius gibelio. Excitatory and inhibitory influences across receptive fields of orientation-selective units were evaluated. Positions, sizes and forms of the responsive parts of the receptive field were estimated by moving edges and flashing narrow light and dark stripes. It was shown that the orientation-selective units in fish are characterized by small responsive receptive fields with mean width of 4.8 +/- 1.6 degrees (n = 176). The comparison of different types of orientation-selective units revealed that the responsive receptive fields of detectors of vertical lines are significantly wider (13%) than those of detectors of horizontal lines. Statistically significant difference was also found between sizes of responsive receptive fields evaluated by light and dark edges. Mean responsive receptive field width, estimated for light edges (ON responses) were wider than those evaluated for dark edges (OFF responses). Inhibition in the receptive field of orientation-selective units was evaluated on the basis of two experimental methods. Evidence that signals are not linearly summed across the receptive field was derived from experimental results. Inhibitory influences, recorded in the receptive field of orientation-selective units, always initiated inside the responsive receptive field area and spread towards the periphery. Results of the study indicate that receptive fields cannot be defined as homogeneous sensory zone driven by a linear mechanism of response generation. The receptive fields of orientation-selective units, in fish appear to be composed of subunits sensitive to the appropriately oriented stimuli.