Rapid dynamics of contrast responses in the cat primary visual cortex.
Rapid dynamics of contrast responses in the cat primary visual cortex.
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DOI：
10.1371/journal.pone.0025410
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Hu M;Wang Y;Wang Y
我们在自然视觉过程中接收到的视觉信息会迅速而持续地变化。视觉系统必须适应环境的时空内容，以便有效地处理动态信号。然而，神经元对亮度对比度的反应通常是使用漂移或长时间呈现的静止栅来测量的。由于我们视野中的运动是连续的，视觉系统接收到的信号在对比域内包含大量的瞬时分量。本文采用一种改进的反向相关方法，研究了猫初级视皮层神经元对40ms静态和瞬时呈现的不同对比度的反应特性，结果表明，神经元能够有效地区分快速变化的对比度。对比反应函数(CRF)随时间的变化主要包括时间反应发展阶段的对比增益增加(CRF左移)和衰减期反应增益的降低(CRF下移)。当刺激对比度分布范围增大时，神经元的对比度增益和反应增益减小。我们的结果表明，对比度增益控制(对比度适应)和反应增益控制机制在刺激开始后的前几十毫秒内被很好地建立，并可能协同地调节视觉皮层神经元对连续变化的对比度的快速动态反应。这种快速对比度自适应可以在检测快速变化的视觉场景的上下文中的对比度轮廓方面发挥作用。
The visual information we receive during natural vision changes rapidly and continuously. The visual system must adapt to the spatiotemporal contents of the environment in order to efficiently process the dynamic signals. However, neuronal responses to luminance contrast are usually measured using drifting or stationary gratings presented for a prolonged duration. Since motion in our visual field is continuous, the signals received by the visual system contain an abundance of transient components in the contrast domain. Here using a modified reverse correlation method, we studied the properties of responses of neurons in the cat primary visual cortex to different contrasts of grating stimuli presented statically and transiently for 40 ms, and showed that neurons can effectively discriminate the rapidly changing contrasts. The change in the contrast response function (CRF) over time mainly consisted of an increment in contrast gain (CRF shifts to left) in the developing phase of temporal responses and a decrement in response gain (CRF shifts downward) in the decay phase. When the distribution range of stimulus contrasts was increased, neurons demonstrated decrement in contrast gain and response gain. Our results suggest that contrast gain control (contrast adaptation) and response gain control mechanisms are well established during the first tens of milliseconds after stimulus onset and may cooperatively mediate the rapid dynamic responses of visual cortical neurons to the continuously changing contrast. This fast contrast adaptation may play a role in detecting contrast contours in the context of visual scenes that are varying rapidly.
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影响因子：
64.8
作者：
Gutnisky, Diego A.;Dragoi, Valentin
通讯作者：
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影响因子：
25
作者：
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DOI：
10.1073/pnas.022638499
发表时间：
2002-02-05
影响因子：
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