Relationship of Prefrontal GABA to Inhibitory Mechanisms for Response Preparation

描述（由申请人提供）：该R21提案旨在采用磁共振波谱（MRS）协议来检查前额皮质中抑制性神经递质γ -氨基丁酸（GABA）与运动系统动力学之间的关系，这些运动是通过经颅磁刺激（TMS）测量的。在PI实验室进行的经颅磁刺激研究已经分离出两种有助于选择和启动反应的抑制机制。一种机制有助于解决共同激活反应之间的竞争，并与外侧前额皮质有关。另一种机制有助于防止选择反应的冲动执行，并与背侧运动前皮层有关。然而，这两种抑制过程与相关额叶皮质区域内GABA水平的关系尚未被研究。拟议的项目将调查这种关系

DESCRIPTION (provided by applicant): This R21 proposal aims to employ a magnetic resonance spectroscopy (MRS) protocol to examine the relationship between the inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), in the frontal cortex and motor system dynamics during the selection and initiation of movements as measured with transcranial magnetic stimulation (TMS) of the motor cortex. TMS studies conducted in the PI's laboratory have dissociated two inhibitory mechanisms that contribute to the selection and initiation of responses. One mechanism helps to resolve competition among co-activated responses and is associated with lateral prefrontal cortex. The other mechanism helps prevent impulsive execution of a selected response and is associated with dorsal premotor cortex. However, the relationship of these two inhibitory processes to levels of GABA within their associated frontal cortical regions has not been investigated. The proposed project will investigate this relationship through the study of individual differences at the neurochemical and neurophysiological level. The project represents a new research direction for the PI, yet is highly feasible. The PI is an expert on the motor system and the use of TMS as a tool for investigating the dynamics of response preparation. The co-investigator Dr. Richard Maddock is an expert in the use of MRS methods, specifically for measuring GABA. With Dr. Maddock's guidance, and the recent installation of MRS software at UC Berkeley, the infrastructure is in place for this work.