Changes in Category Selectivity in Visual Association Cortex After PFC Impairment

描述（由申请人提供）：本项目旨在了解前额皮质（PFC）在调节后视关联皮层（VAC）类别表征中的作用。PFC调节对这些区域的因果效应将在局灶性PFC损伤患者和接受单侧PFC区域经颅磁刺激（TMS）的健康受试者中进行测试。这些群体执行选择性注意任务的能力涉及特定类别的皮层区域，以及相应的功能性磁共振成像（fMRI）数据模式，将提供有关这种自上而下的调制如何发生的信息。这里使用的任务是根据呈现的视野来分离半球反应。分类选择性的多种测量方法将应用于数据，以评估假设的与PFC损伤相同半球的VAC选择性降低。此外，对先前两个实验中获得的功能磁共振成像数据进行多变量分析将确定受损半球和完整半球之间连通性的变化。公共卫生相关性：从这项工作中获得的关于PFC和视觉皮层之间耦合的基本知识可能具有基本的临床意义。大量的疾病与额叶功能障碍有关，至少部分与额叶功能障碍有关。这些疾病包括精神疾病，如精神分裂症、注意力缺陷多动障碍（ADHD）、强迫症和重度抑郁症，以及一些结构性和退行性脑部疾病，如帕金森病（PD）和阿尔茨海默病（AD）。了解PFC在自上而下调节中的作用可以指导定向评估的发展，从而改进诊断和治疗。

DESCRIPTION (provided by applicant): This project is directed towards understanding the role of the prefrontal cortex (PFC) in modulating category representations in posterior visual association cortex (VAC). The causal effect of PFC modulation on these regions will be tested in patients with focal PFC damage and healthy subjects who have undergone transcranial magnetic stimulation (TMS) of a unilateral PFC region. The ability of these groups to perform a selective attention task that engages category-specific regions of cortex as well as the corresponding pattern of functional magnetic resonance imaging (fMRI) data will provide information about how this top-down modulation occurs. The task used here is designed to segregate the hemispheric responses according to the visual field of presentation. Multiple measures of category selectivity will be applied to the data to assess the hypothesized decrease in selectivity in VAC in the same hemisphere as the PFC impairment. Further, a multivariate analysis of the fMRI data obtained in the two previously described proposed experiments will identify changes in connectivity between the impaired and intact hemispheres. PUBLIC HEALTH RELEVANCE: Basic knowledge about the coupling between PFC and visual cortex gained from this work may be of fundamental clinical significance. A large number of disorders are associated, at least in part, with dysfunction of the frontal lobes. These include psychiatric disorders, such as schizophrenia, attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, and major depression, as well as a number of structural and degenerative brain diseases including Parkinson's Disease (PD)and Alzheimer's Disease (AD). Knowledge of the role of PFC in top-down modulation may guide development of directed assessments that can refine diagnosis and treatment.