Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
Neuron. 2021 May 19;109(10):1707-1720.e7. doi: 10.1016/j.neuron.2021.03.020. Epub 2021 Apr 6.
Active haptic sensation is critical for object identification, but its neural circuit basis is poorly understood. We combined optogenetics, two-photon imaging, and high-speed behavioral tracking in mice solving a whisker-based object orientation discrimination task. We found that orientation discrimination required animals to summate input from multiple whiskers specifically along the whisker arc. Animals discriminated the orientation of the stimulus per se as their performance was invariant to the location of the presented stimulus. Populations of barrel cortex neurons summated across whiskers to encode each orientation. Finally, acute optogenetic inactivation of the barrel cortex and cell-type-specific optogenetic suppression of layer 4 excitatory neurons degraded performance, implying that infragranular layers alone are not sufficient to solve the task. These data suggest that spatial summation over an active haptic array generates representations of an object's orientation, which may facilitate encoding of complex three-dimensional objects during active exploration.
主动触觉感知对于物体识别至关重要，但它的神经回路基础还了解甚少。我们在解决基于胡须的物体方向辨别任务的小鼠中结合了光遗传学、双光子成像和高速行为跟踪。我们发现，方向辨别要求动物沿着胡须弧累加来自多个胡须的输入。动物辨别刺激的方向本身，因为它们的表现对呈现刺激的位置不变。桶状皮层神经元的群体在胡须之间进行求和以编码每个方向。最后，急性光遗传学失活桶状皮层和细胞类型特异性光遗传学抑制第四层兴奋性神经元降低了性能，这表明仅 infragranular 层不足以解决该任务。这些数据表明，主动触觉阵列上的空间求和生成了物体方向的表示，这可能有助于在主动探索期间对复杂的三维物体进行编码。
