Consequences of developmental defects in somatosensory map formation

描述(由申请人提供)：大脑中感觉空间的地形图表示对于感觉信息处理和感知是必不可少的。每个半球的躯体感觉和运动皮质图代表对侧的身体和面部。这是由于上升(感觉)和下降(运动)通路在延髓或桥脑水平的中线交叉所致。中线交叉的遗传和发育缺陷或交叉部位的损伤严重影响动物和人类的感觉-运动信息处理和行动。在这项建议中，我们使用区域特异性基因缺失的小鼠模型来研究上升的体感脸部通路部分交叉的后果。这只小鼠的中线交叉缺陷导致丘脑和随后的躯体感觉皮层出现双侧面部表征。我们将使用这个小鼠模型来研究(A)“双面”皮质图中突触前和突触后元素的形态和电生理特性；(B)丘脑皮质和皮质连接模式的改变，以响应双侧面部表征；(C)这种基因突变的行为后果。将结合分子、形态、电生理、电压敏感染料成像和行为技术来阐明在上升体感通路中发育损伤相关或遗传缺陷的功能组织和行为表现的机制。

DESCRIPTION (provided by applicant): Topographic representation of the sensory space in the brain is essential for sensory information processing and perception. The somatosensory and motor cortical maps in each hemisphere represent the contralateral body and the face. This is due to midline crossing of the ascending (sensory) and descending (motor) pathways at the level of the medulla or the pons. Genetic and developmental defects in midline crossing or injury at the crossing site severely affect sensory-motor information processing and actions in both animals and humans. In this proposal we use a region-specific gene deletion mouse model to study the consequences of partial crossing of the ascending somatosensory face pathway. Midline crossing defects in this mouse leads to bilateral face representation in the thalamus and subsequently in the somatosensory cortex. We will use this mouse model to investigate (a) morphological and electrophysiological properties of the pre and postsynaptic elements in the "bifacial" cortical map; (b) altered thalamocortical and corticocortical connectivity patterns in response to bilateral face representation; (c) behavioral consequences of this genetic mutation. A combination of molecular, morphological, electrophysiological, voltage-sensitive dye imaging and behavioral techniques will be used to elucidate mechanisms underlying the functional organization and behavioral manifestations of developmental injury-related or genetic defects in ascending somatosensory pathways.