Lee Charles C, Lam Ying-Wan, Sherman S Murray
Department of Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana 70803, USA.
Neuroreport. 2012 Aug 22;23(12):736-40. doi: 10.1097/WNR.0b013e328356c1aa.
Axonal branches from a subset of neurons in cerebral cortical layer 6 innervate both cortical layer 4 and the thalamus. As such, these neurons are poised to modulate thalamocortical transmission at multiple forebrain sites. Here, we examined the functional organization of the layer 6 intracortical projections in auditory, somatosensory, and visual cortical areas using an optogenetic approach to specifically target these neurons. We characterized the anatomical and physiological organization of these projections using laser-scanning photostimulation to functionally map the elicited postsynaptic responses in layer 4. We found that these responses originated from regions over 1 mm in width, eliciting short-term facilitating responses. These results indicate that intracortical modulation of layer 4 occurs through widespread layer 6 projections in each sensory cortical area.
大脑皮层第6层中一部分神经元的轴突分支支配着皮层第4层和丘脑。因此，这些神经元能够在多个前脑部位调节丘脑皮质传递。在这里，我们使用光遗传学方法特异性地靶向这些神经元，研究了听觉、体感和视觉皮层区域中第6层皮质内投射的功能组织。我们使用激光扫描光刺激在功能上绘制第4层中诱发的突触后反应，以此来表征这些投射的解剖和生理组织。我们发现这些反应源自宽度超过1毫米的区域，引发短期促进反应。这些结果表明，第4层的皮质内调节是通过每个感觉皮层区域中广泛的第6层投射来实现的。
