Department of Neuroscience, Columbia University, New York, United States.
Department of Physiology, Anatomy, & Genetics, University of Oxford, Oxford, United Kingdom.
Elife. 2024 Nov 27;13:RP97188. doi: 10.7554/eLife.97188.
Each sensory modality has its own primary and secondary thalamic nuclei. While the primary thalamic nuclei are well understood to relay sensory information from the periphery to the cortex, the role of secondary sensory nuclei is elusive. We trained head-fixed mice to attend to one sensory modality while ignoring a second modality, namely to attend to touch and ignore vision, or vice versa. Arrays were used to record simultaneously from the secondary somatosensory thalamus (POm) and secondary visual thalamus (LP). In mice trained to respond to tactile stimuli and ignore visual stimuli, POm was robustly activated by touch and largely unresponsive to visual stimuli. A different pattern was observed when mice were trained to respond to visual stimuli and ignore touch, with POm now more robustly activated during visual trials. This POm activity was not explained by differences in movements (i.e. whisking, licking, pupil dilation) resulting from the two tasks. Post hoc histological reconstruction of array tracks through POm revealed that subregions varied in their degree of plasticity. LP exhibited similar phenomena. We conclude that behavioral training reshapes activity in secondary thalamic nuclei. Secondary nuclei respond to the same behaviorally relevant, reward-predicting stimuli regardless of stimulus modality.
每种感觉模式都有其自己的初级和次级丘脑核。虽然初级丘脑核被很好地理解为将感觉信息从外围传递到皮层，但次级感觉核的作用仍难以捉摸。我们训练头部固定的老鼠专注于一种感觉模式，同时忽略第二种模式，即专注于触觉而忽略视觉，或者反之亦然。我们使用数组同时从次级体感丘脑（POm）和次级视觉丘脑（LP）中进行记录。在接受训练以响应触觉刺激并忽略视觉刺激的老鼠中，POm 被触觉强烈激活，而对视觉刺激的反应则很小。当老鼠接受训练以响应视觉刺激并忽略触觉时，观察到了不同的模式，此时 POm 在视觉试验中更强烈地激活。这种 POm 活性不能用两种任务引起的运动（即胡须摆动、舔舐、瞳孔扩张）差异来解释。通过 POm 对数组轨迹进行的事后组织学重建表明，亚区在其可塑性程度上有所不同。LP 也表现出类似的现象。我们得出结论，行为训练重塑了次级丘脑核中的活动。次级核对相同的与行为相关、预测奖励的刺激做出反应，而与刺激模式无关。
