Institute for Neuroscience, Technische Universität München, Biedersteiner Straβe 29, 80802 Munich, Germany.
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straβe 22, 81675 Munich, Germany.
Cell Rep. 2016 Jan 12;14(2):208-15. doi: 10.1016/j.celrep.2015.12.026. Epub 2015 Dec 31.
In the mammalian brain, thalamic signals reach the cortex via two major routes: primary and higher-order thalamocortical pathways. While primary thalamocortical nuclei transmit sensory signals from the periphery, the function of higher-order thalamocortical projections remains enigmatic, in particular their role in sensory processing in the cortex. Here, by optogenetically controlling the thalamocortical pathway from the higher-order posteromedial thalamic nucleus (POm) during whisker stimulation, we demonstrate the integration of the two thalamocortical streams by single pyramidal neurons in layer 5 (L5) of the mouse barrel cortex under anesthesia. We report that POm input mainly enhances sub- and suprathreshold activity via net depolarization. Sensory enhancement is accompanied by prolongation of cortical responses over long (800-ms) periods after whisker stimulation. Thus, POm amplifies and temporally sustains cortical sensory signals, possibly serving to accentuate highly relevant sensory information.
在哺乳动物大脑中，丘脑信号通过两条主要途径到达皮层：初级和高级丘脑皮质通路。虽然初级丘脑皮质核从外围传递感觉信号，但高级丘脑皮质投射的功能仍然是神秘的，特别是它们在皮层中感觉处理中的作用。在这里，通过在胡须刺激期间光遗传学控制来自高级后内侧丘脑核（POm）的丘脑皮质通路，我们证明了在麻醉下，小鼠桶状皮层第 5 层（L5）中的单个锥体神经元整合了这两条丘脑皮质流。我们报告说，POm 输入主要通过净去极化来增强亚阈值和阈值以上的活性。感觉增强伴随着皮质反应在胡须刺激后长（800ms）时期的延长。因此，POm 放大并暂时维持皮质感觉信号，可能有助于突出高度相关的感觉信息。
