The temporal properties of the response of macaque ganglion cells and central mechanisms of flicker detection
The temporal properties of the response of macaque ganglion cells and central mechanisms of flicker detection
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DOI：
10.1167/7.14.1
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发表时间：
2007-01-01
影响因子：
1.8
通讯作者：
Zucchini, Walter
中科院分区：
文献类型：
--
作者：
Lee, Barry B.;Sun, Hao;Zucchini, Walter
该分析评估了灵长类动物神经节细胞作为时间频率的函数的正弦调制的敏感性，基于其脉冲序列的结构;将对亮度和色度调制的敏感性与人类对类似刺激的心理物理敏感性进行比较。每个刺激周期进行傅立叶分析，并响应幅度进行神经测量分析;这假设检测器的持续时间与频率成反比，也就是说，分析的刺激时期是一个单一的周期，而不是一个固定的持续时间，并提供了一个上限的检测由观察者谁的判断基础上的一个细胞。对于一个给定的傅立叶振幅的信噪比迅速下降的时间频率。这是组成响应的脉冲序列统计的结果;在较高的时间频率下，每个周期的脉冲较少。然后将这种“单细胞”观察器的性能与固定持续时间的建模中央检测机制的性能进行比较。对于色度调制，在小细胞（PC）通路上操作的具有类似于40 ms的时间常数的滤波器/检测器提供了与心理物理结果的匹配，而对于亮度调制，在大细胞（MC）通路上操作的具有类似于5-10 ms的时间常数的滤波器/检测机制提供了合适的匹配。细胞输入检测之间的求和和非线性相互作用的影响也被认为是在增强的灵敏度和“锐度”的阈值，即神经功能的陡度。对于亮度（MC单元）和色度调制（PC单元），受限会聚（< 20个单元）似乎足以提供与心理物理性能相当的尖锐阈值和灵敏度。
This analysis assesses sensitivity of primate ganglion cells to sinusoidal modulation as a function of temporal frequency, based on the structure of their impulse trains; sensitivity to luminance and chromatic modulation was compared to human psychophysical sensitivity to similar stimuli. Each stimulus cycle was Fourier analyzed, and response amplitudes subjected to neurometric analysis; this assumes a detector with duration inversely proportional to frequency, that is, the stimulus epoch analyzed is a single cycle rather than a fixed duration, and provides an upper bound for a detection by an observer who bases judgments on a single cell. Signal-to-noise ratio for a given Fourier amplitude rapidly decreased with temporal frequency. This is a consequence of the statistics of impulse trains making up the response; at higher temporal frequencies, there are fewer impulses per cycle. Performance of this "single-cell" observer was then compared with that of modeled central detection mechanisms of fixed duration. For chromatic modulation, a filter/detector with a time constant of similar to 40 ms operating upon the parvocellular (PC) pathway provided a match to psychophysical results, whereas for luminance modulation, a filter/detection mechanism operating upon the magnocellular (MC) pathway with a time constant of similar to 5-10 ms provided a suitable match. The effects of summation and nonlinear interactions between cell inputs to detection are also considered in terms of enhanced sensitivity and "sharpness" of thresholds, that is, the steepness of the neurometric function. For both luminance (MC cells) and chromatic modulation (PC cells), restricted convergence (< 20 cells) appears adequate to provide sharp thresholds and sensitivity comparable to psychophysical performance.