Contrast coding in the primary visual cortex depends on temporal contexts
Contrast coding in the primary visual cortex depends on temporal contexts
复制标题
初级视觉皮层中的对比编码取决于时间背景
DOI：
10.1111/ejn.13893
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发表时间：
2018-04-01
影响因子：
3.4
通讯作者：
Wang, Yi
中科院分区：
文献类型：
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作者：
Dai, Ji;Wang, Yi
长期以来，初级视觉皮质(V1)的对比反应功能一直被描述为遵循S型曲线。然而，这主要是基于在稳定刺激中测量神经对漂移对比栅的反应，该模型没有考虑运动或刺激呈现的长度的影响。在自然视觉过程中，视觉系统可以获得足够的信息来识别由对比定义的形状，只需一目了然；在如此短的时间尺度内获得更多关于神经元反应特性的知识对于理解潜在的机制是必要的。我们研究了猫V1神经元对静态光栅连续40ms和漂移光栅连续2000ms所呈现的对比的反应。神经元对短暂对比的反应可以用线性函数来很好地描述。进一步研究运动和呈现持续时间对对比反应的影响表明，运动在低对比度范围内提高了反应敏感性，而简短呈现则在高对比度范围内提高了反应敏感性。运动和长时间的呈现(适应)共同导致了在高对比度范围内具有饱和响应的渐近S形曲线。这些结果表明，运动主要增强对低对比度物体的神经反应敏感性，而短而快的呈现主要增强神经对高对比度刺激的敏感性。我们的研究结果表明，多个因素影响对比反应函数的特性，这表明V1神经元的对比编码是灵活的，并且依赖于时间语境。
Contrast response function in the primary visual cortex (V1) has long been described as following a sigmoid curve. However, this is mainly based on measuring neural responses to drifting contrast grating in a stable stimulation, a model that does not consider the effects of motion or length of stimulus presentation. During natural viewing, the visual system can obtain sufficient information for identifying the shapes defined by contrast from a single glance; acquiring greater knowledge of the neuronal response properties to contrast in such a short timescale is necessary to understand the underlying mechanisms. We investigated responses of cat V1 neurons to contrast presented by static grating for 40 ms without pause compared to drifting grating presented continuously for 2000 ms. The neuronal response to transiently presented contrast could be well described by a linear function. Further examination of the effects of motion and presentation duration on contrast responses demonstrated that motion increased response sensitivity in the low‐contrast range, while brief presentation increased response sensitivity in the high‐contrast range. Motion and prolonged presentation (adaptation) together resulted in an asymptotic sigmoid curve with a saturation response in the high‐contrast range. These results suggest that motion mainly enhance the neural response sensitivity to low‐contrast objects, while short and rapid presentation mainly enhance the neural sensitivity to high‐contrast stimulus. Our findings indicate that multiple factors influence the properties of contrast response functions, suggesting that V1 neuron contrast coding is flexible and depends on the temporal contexts.