Substance P and the tectothalamic pathway

拟议的实验的长期目标是确定注意障碍的原因 疾病。但是，首先必须了解可能有助于实现以下目标的电路组织 正常大脑中的注意力机制。许多研究都认为枕核是一个 可以调节视觉注意力。啮齿类动物的外侧后核(LP)是一个与下部相当的区域 灵长类枕核的区域。啮齿动物的LP核由纤维支配，这些纤维含有 神经肽P物质，一种已知的促进神经元放电特性的神经调节剂。Lp核 从上丘区域内的投射细胞接受视觉输入，即P物质- 免疫反应阳性。示踪、免疫细胞化学、电子显微镜和体外实验相结合 电生理学将被用来检查突触的组织和功能特性。 丘脑通路。从顶盖-丘脑终末释放P物质和谷氨酸可能 增强和增强上丘的谷氨酸能输入。因为Lp核投射到 视皮层，即顶盖-丘脑通路，可以通过调节皮质回路来影响视觉注意。

The long term goal of the proposed experiments is to determine the causes of attention impairment during disease. However, it is first necessary to understand the organization of circuits that may contribute to attention mechanisms in the normal brain. Many studies have implicated the pulvinar nucleus as an area that may regulate visual attention. The rodent lateral posterior (LP) nucleus is a region comparable to inferior regions of the primate pulvinar nucleus. The rodent LP nucleus is innervated by fibers which contain the neuropeptide substance P, a neuromodulator known to facilitate neuronal firing properties. The LP nucleus receives visual input from projection cells within an area of the superior colliculus that is substance P- immunoreactive. A combination of tract tracing, immunocytochemistry, electron microscopy and in vitro electrophysiology will be used to examine the synaptic organization and functional properties of the tecto- thalamic pathway. Concomitant release of substance P with glutamate from tecto-thalamic terminals might enhance and potentiate glutamatergic input from the superior colliculus. Because the LP nucleus projects to the visual cortex, the tecto-thalamic pathway could affect visual attention by modulating cortical circuitry.