Orientation tuning, but not direction selectivity, is invariant to temporal frequency in primary visual cortex
Orientation tuning, but not direction selectivity, is invariant to temporal frequency in primary visual cortex
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DOI：
10.1152/jn.01224.2004
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发表时间：
2005-08-01
影响因子：
2.5
通讯作者：
Usrey, WM
中科院分区：
文献类型：
--
作者：
Moore, BD;Alitto, HJ;Usrey, WM
初级视皮层神经元的活动受到视觉刺激的方向、对比度和时间频率的影响。这就提出了一个问题，即这些刺激特性如何相互作用以形成神经元反应。虽然过去的研究表明，方向调谐的带宽是不变的刺激对比度，时间频率的方向调谐带宽的影响是未知的。在这里，我们调查的时间频率的雪貂视皮层17区的方向调谐和方向选择性的影响。对于简单细胞和复杂细胞，方向调谐带宽（半峰响应的半宽）的测量在很宽的时间频率范围内类似于20 - 25度。因此，皮层神经元显示时间频率不变的方向调谐。相反，方向选择性通常会降低，偶尔会逆转，在非首选的时间频率。这些结果表明，有助于产生的方向调谐和方向选择性的机制是不同的视觉刺激的时间频率的影响，并支持的概念，方向调谐的稳定性是视觉处理的一个重要方面。
The activity of neurons in primary visual cortex is influenced by the orientation, contrast, and temporal frequency of a visual stimulus. This raises the question of how these stimulus properties interact to shape neuronal responses. While past studies have shown that the bandwidth of orientation tuning is invariant to stimulus contrast, the influence of temporal frequency on orientation-tuning bandwidth is unknown. Here, we investigate the influence of temporal frequency on orientation tuning and direction selectivity in area 17 of ferret visual cortex. For both simple cells and complex cells, measures of orientation-tuning bandwidth (half-width at half-maximum response) are similar to 20-25 degrees across a wide range of temporal frequencies. Thus cortical neurons display temporal-frequency invariant orientation tuning. In contrast, direction selectivity is typically reduced, and occasionally reverses, at nonpreferred temporal frequencies. These results show that the mechanisms contributing to the generation of orientation tuning and direction selectivity are differentially affected by the temporal frequency of a visual stimulus and support the notion that stability of orientation tuning is an important aspect of visual processing.