Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
Neuroscience. 2018 May 21;379:359-374. doi: 10.1016/j.neuroscience.2018.03.039. Epub 2018 Mar 30.
In the primary visual cortex (V1), neuronal responses to stimuli within the receptive field (RF) are modulated by stimuli in the RF surround. A common effect of surround modulation is surround suppression, which is dependent on the feature difference between stimuli within and surround the RF and is suggested to be involved in the perceptual phenomenon of figure-ground segregation. In this study, we examined the relationship between feature-specific surround suppression of V1 neurons and figure detection behavior based on figure-ground feature difference. We trained freely moving mice to perform a figure detection task using figure and ground gratings that differed in spatial phase. The performance of figure detection increased with the figure-ground phase difference, and was modulated by stimulus contrast. Electrophysiological recordings from V1 in head-fixed mice showed that the increase in phase difference between stimuli within and surround the RF caused a reduction in surround suppression, which was associated with an increase in V1 neural discrimination between stimuli with and without RF-surround phase difference. Consistent with the behavioral performance, the sensitivity of V1 neurons to RF-surround phase difference could be influenced by stimulus contrast. Furthermore, inhibiting V1 by optogenetically activating either parvalbumin (PV)- or somatostatin (SOM)-expressing inhibitory neurons both decreased the behavioral performance of figure detection. Thus, the phase-specific surround suppression in V1 represents a neural correlate of figure detection behavior based on figure-ground phase discontinuity.
在初级视皮层（V1）中，神经元对感受野（RF）内刺激的反应受到 RF 周围刺激的调制。周围调制的一个常见效果是周围抑制，它依赖于 RF 内和周围刺激之间的特征差异，被认为与图形-背景分离的感知现象有关。在这项研究中，我们研究了 V1 神经元的特征特异性周围抑制与基于图形-背景特征差异的图形检测行为之间的关系。我们训练自由移动的老鼠使用在空间相位上不同的图形和背景光栅来执行图形检测任务。图形检测的性能随图形-背景相位差的增加而增加，并受到刺激对比度的调制。在头固定老鼠的 V1 中进行的电生理记录显示，RF 内和周围刺激之间相位差的增加导致周围抑制的减少，这与 V1 神经元对有和没有 RF-周围相位差的刺激的区分能力的增加有关。与行为表现一致，刺激对比度可以影响 V1 神经元对 RF-周围相位差的敏感性。此外，通过光遗传学激活表达 Parvalbumin（PV）或 Somatostatin（SOM）的抑制性神经元来抑制 V1，都降低了图形检测的行为表现。因此，V1 中的相位特异性周围抑制代表了基于图形-背景相位不连续性的图形检测行为的神经关联。
