During active tactile exploration, the dynamic patterns of touch are transduced to electrical signals and transformed by the brain into a mental representation of the object under investigation. This transformation from sensation to perception is thought to be a major function of the mammalian cortex. In primary somatosensory cortex (S1) of mice, layer 5 (L5) pyramidal neurons are major outputs to downstream areas that influence perception, decision-making, and motor control. We investigated self-motion and touch representations in L5 of S1 with juxtacellular loose-seal patch recordings of optogenetically identified excitatory neurons. We found that during rhythmic whisker movement, 54 of 115 active neurons (47%) represented self-motion. This population was significantly more modulated by whisker angle than by phase. Upon active touch, a distinct pattern of activity was evoked across L5, which represented the whisker angle at the time of touch. Object location was decodable with submillimeter precision from the touch-evoked spike counts of a randomly sampled handful of these neurons. These representations of whisker angle during self-motion and touch were independent, both in the selection of which neurons were active and in the angle-tuning preference of coactive neurons. Thus, the output of S1 transiently shifts from a representation of self-motion to an independent representation of explored object location during active touch.

在主动触觉探索过程中，触摸的动态模式被转换为电信号，并由大脑转化为所研究对象的心理表征。这种从感觉到知觉的转变被认为是哺乳动物皮质的主要功能。在小鼠的初级体感皮层 (S1) 中，第 5 层 (L5) 锥体神经元是影响感知、决策和运动控制的下游区域的主要输出。我们通过光遗传学识别的兴奋性神经元的近细胞松散密封贴片记录，研究了 S1 的 L5 中的自我运动和触摸表征。我们发现，在有节奏的胡须运动过程中，115 个活跃神经元中有 54 个（47%）代表自我运动。该群体受晶须角度的调节明显多于相位。在主动触摸时，L5 会引发一种独特的活动模式，它代表触摸时的胡须角度。通过随机采样的少数神经元的触摸诱发尖峰计数，可以以亚毫米精度解码物体位置。自我运动和触摸过程中胡须角度的这些表示是独立的，无论是在选择哪些神经元处于活动状态还是在协同神经元的角度调节偏好方面都是独立的。因此，在主动触摸期间，S1 的输出瞬时从自身运动的表示转变为探索对象位置的独立表示。