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叶皮层（PFC）在调节后视觉关联皮层（VAC）中的类别表征中的作用。将在局灶性PFC损伤患者和接受单侧PFC区域经颅磁刺激（TMS）的健康受试者中测试PFC调制对这些区域的因果效应。这些群体执行选择性注意任务的能力，以及功能性磁共振成像（fMRI）数据的相应模式，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。将对数据应用类别选择性的多种测量，以评估与PFC损伤相同半球中VAC选择性的假设降低。此外，多变量分析的功能磁共振成像数据中获得的两个先前描述的拟议的实验将确定受损和完整的半球之间的连接的变化。公共卫生相关性：从这项工作中获得的有关PFC和视皮层之间的耦合的基本知识可能具有基本的临床意义。许多疾病至少部分与额叶功能障碍有关。这些包括精神障碍，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，以及许多结构性和退行性脑疾病，包括帕金森病（PD）和阿尔茨海默病（AD）。了解PFC在自上而下的调节中的作用，可以指导定向评估的发展，从而改善诊断和治疗。

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.