MODELS OF NORMAL & POSTSTROKE HEMISPHERIC INTERACTIONS

目前对大脑特化和半球相互作用起源的理解相当有限。例如，目前尚不清楚哪些已知的皮质不对称会导致侧化，一个半球对另一个半球的净影响是兴奋性的还是抑制性的，以及完整的对侧半球在多大程度上有助于中风等皮质损伤后的恢复。这项工作的长期目标是通过开发和研究紧急半球偏侧和半球相互作用的神经模型来更好地理解这些问题，因为这些模型从模拟皮层损伤中恢复。该模型由由模拟胼胝体连接的成对的左、右皮质区域组成。具体目标是：1。为了验证模型具有兴奋性胼胝体连接和间接半球间竞争的假设，可以比以前的模型更好地解释生物/行为实验数据；2. 确定学习一项行为任务如何影响另一项任务的偏侧化方向/程度；3. 确定单个模型中多个潜在的半球不对称如何相互作用，改变每一个单独产生的偏侧化的方向/程度；和4。研究以神经生物学为基础的联想词学习模型中的侧化和损伤后半球相互作用，该模型可直接与行为、临床和功能成像数据进行比较。这是利用计算模型更好地理解大脑特化和经胼胝体裂的第一次系统尝试。该结果将直接关系到正在进行的实验工作，对当前脑半球功能不对称和脑卒中后恢复机制的理论具有重要意义，并可能为脑卒中患者提供新的治疗理念。

Current understanding of the origins of cerebral specialization and of hemispheric interactions is fairly limited. For example, it is unclear which recognized cortical asymmetries lead to lateralization, whether the net influence of one hemisphere on the other is excitatory or inhibitory, and to the extent to which the intact contralateral hemisphere contributes to recovery following a cortical lesion such as a stroke. The long-term goal of this work is to gain a better understanding of these issues by developing and studying neural models of emergent hemispheric lateralization and of hemispheric interactions as those models recover from simulated cortical lesions. The models consist of networks of paired left and right cortical regions connected by a simulated corpus callosum. The specific aims are: 1. to test the hypothesis that models have excitatory callosal connections and indirect interhemispheric competition can better explain data from biological/behavioral experiments than previous models; 2. to determine how learning one behavioral task can influence the direction/extent of another task's lateralization; 3. to determine how multiple underlying hemispheric asymmetries in a single model interact, altering the direction/extent of lateralization produced by each alone; and 4. to examine lateralization and post-lesion hemispheric interactions in a neurobiologically-grounded model of associative word learning that is directly comparable to behavioral, clinical and functional imaging data. This is the first systematic attempt to better understand cerebral specialization and transcallosal diaschisis using computational models. The results will directly relate to ongoing experimental work, have important implications for current theories of the mechanisms underlying hemispheric functional asymmetries and post-stroke recovery, and may suggest new therapeutic concepts for stroke patients.