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质(PFC)在调节后部视觉联想皮质(VAC)类别表征中的作用。PFC调制对这些区域的因果效应将在局灶性PFC受损患者和接受过单侧PFC区域经颅磁刺激(TMS)的健康受试者中进行测试。这些小组执行选择性注意任务的能力，涉及大脑皮层特定类别的区域以及相应的功能磁共振成像(FMRI)数据模式，将提供有关这种自上而下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大脑半球的反应。将对数据应用多种类别选择性测量，以评估假设的与PFC损害相同的半球内VAC选择性的下降。此外，对前面描述的两个拟议实验中获得的功能磁共振数据进行多变量分析，将确定受损和完好大脑半球之间的连接变化。公共卫生相关性：从这项工作中获得的关于PFC和视皮层之间耦合的基本知识可能具有基本的临床意义。大量的疾病至少部分与额叶功能障碍有关。这些疾病包括精神障碍，如精神分裂症、注意力缺陷多动障碍(ADHD)、强迫症和严重抑郁症，以及一些结构性和退行性大脑疾病，包括帕金森氏症(PD)和阿尔茨海默病(AD)。对PFC在自上而下调节中的作用的了解可能会指导指导评估的发展，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.