Substance P and the tectothalamic pathway

描述（由申请人提供）：拟议实验的长期目标是确定疾病期间注意力障碍的原因。然而，首先有必要了解正常大脑中可能有助于注意机制的回路组织。许多研究暗示枕核是一个可能调节视觉注意力的区域。啮齿类动物的外侧后核（LP）是一个与灵长类动物枕核的下核相当的区域。啮齿动物LP核由含有神经肽P物质的纤维支配，P物质是一种促进神经元放电特性的神经调节剂。LP核接收来自上丘区域内P物质免疫反应性投影细胞的视觉输入。结合束示踪，免疫细胞化学，电子显微镜和体外电生理学将被用来检查突触组织和功能特性的构造-丘脑通路。P物质与谷氨酸同时从丘脑顶端释放可能增强和增强上丘的谷氨酸能输入。由于LP核投射到视觉皮层，因此构造-丘脑通路可能通过调节皮层回路来影响视觉注意。

DESCRIPTION (provided by applicant): 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.