Institut Pasteur, Université Paris Cité, Unit of Neural Circuits Dynamics and Decision Making, F-75015, Paris, France.
IZKF Aachen, Medical School, RWTH Aachen University, 52074, Aachen, Germany.
Nat Commun. 2024 Jun 5;15(1):4782. doi: 10.1038/s41467-024-49129-9.
During perceptually guided decisions, correlates of choice are found as upstream as in the primary sensory areas. However, how well these choice signals align with early sensory representations, a prerequisite for their interpretation as feedforward substrates of perception, remains an open question. We designed a two alternative forced choice task (2AFC) in which male mice compared stimulation frequencies applied to two adjacent vibrissae. The optogenetic silencing of individual columns in the primary somatosensory cortex (wS1) resulted in predicted shifts of psychometric functions, demonstrating that perception depends on focal, early sensory representations. Functional imaging of layer II/III single neurons revealed mixed coding of stimuli, choices and engagement in the task. Neurons with multi-whisker suppression display improved sensory discrimination and had their activity increased during engagement in the task, enhancing selectively representation of the signals relevant to solving the task. From trial to trial, representation of stimuli and choice varied substantially, but mostly orthogonally to each other, suggesting that perceptual variability does not originate from wS1 fluctuations but rather from downstream areas. Together, our results highlight the role of primary sensory areas in forming a reliable sensory substrate that could be used for flexible downstream decision processes.
在感知引导的决策中，与选择相关的关联可以在初级感觉区域的上游找到。然而，这些选择信号与早期感觉表示的吻合程度如何，即它们作为感知前馈基质的解释的前提条件，仍然是一个悬而未决的问题。我们设计了一个二选一强制选择任务（2AFC），其中雄性小鼠比较施加到两个相邻触须上的刺激频率。初级体感皮层（wS1）中单个柱的光遗传学沉默导致了心理物理函数的预测性移位，表明感知取决于焦点、早期的感觉表示。对层 II/III 单个神经元的功能成像显示出对刺激、选择和任务参与的混合编码。具有多触须抑制的神经元表现出更好的感觉辨别能力，并且在参与任务时其活动增加，从而选择性地增强了与解决任务相关的信号的表示。从一次试验到另一次试验，刺激和选择的表示都发生了很大的变化，但主要是相互正交的，这表明感知的可变性不是源于 wS1 的波动，而是源于下游区域。总之，我们的研究结果强调了初级感觉区域在形成可靠的感觉基质方面的作用，该基质可用于灵活的下游决策过程。
