Taub Daniel G, Jiang Qiufen, Pietrafesa Francesca, Su Junfeng, Greene Caitlin, Blanchard Michael R, Jain Aakanksha, El-Rifai Mahmoud, Callen Alexis, Yager Katherine, Chung Clara, He Zhigang, Chen Chinfei, Woolf Clifford J
F. M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital, Boston, MA, USA.
Department of Neurology, Harvard Medical School, Boston, MA, USA.
Res Sq. 2023 Jun 28:rs.3.rs-2976953. doi: 10.21203/rs.3.rs-2976953/v1.
The cerebral cortex is vital for the perception and processing of sensory stimuli. In the somatosensory axis, information is received by two distinct regions, the primary (S1) and secondary (S2) somatosensory cortices. Top-down circuits stemming from S1 can modulate mechanical and cooling but not heat stimuli such that circuit inhibition causes blunted mechanical and cooling perception. Using optogenetics and chemogenetics, we find that in contrast to S1, an inhibition of S2 output increases mechanical and heat, but not cooling sensitivity. Combining 2-photon anatomical reconstruction with chemogenetic inhibition of specific S2 circuits, we discover that S2 projections to the secondary motor cortex (M2) govern mechanical and thermal sensitivity without affecting motor or cognitive function. This suggests that while S2, like S1, encodes specific sensory information, that S2 operates through quite distinct neural substrates to modulate responsiveness to particular somatosensory stimuli and that somatosensory cortical encoding occurs in a largely parallel fashion.
大脑皮层对于感觉刺激的感知和处理至关重要。在体感轴中，信息由两个不同区域接收，即初级（S1）和次级（S2）体感皮层。源自S1的自上而下的神经回路可以调节机械刺激和冷刺激，但不能调节热刺激，因此回路抑制会导致机械感觉和冷感觉减弱。利用光遗传学和化学遗传学，我们发现与S1不同，抑制S2的输出会增加机械感觉和热感觉，但不会增加冷感觉的敏感性。将双光子解剖重建与特定S2回路的化学遗传学抑制相结合，我们发现S2向次级运动皮层（M2）的投射控制着机械感觉和热感觉，而不影响运动或认知功能。这表明，虽然S2与S1一样编码特定的感觉信息，但S2通过截然不同的神经基质来调节对特定体感刺激的反应，并且体感皮层编码在很大程度上是以并行方式发生的。
