Roles of GABA Inhibition in Learning the Behavior in the Monkey Prefrontal Cortex.

在猕猴额叶(运动皮质、运动前皮质和前额叶皮质)研究了GABA抑制在行为或运动控制中的作用。从运动皮质和运动前皮质记录到单个中子活动，并用离子电泳法应用GABA_A和GABA_B激动剂(Muscimol和Baclofen)以及拮抗剂(Bicuculline和Phaclofen)，同时猴子进行简单的视觉反应时间任务或视觉Go/no-Go任务。激动剂总是抑制运动相关的活动，而拮抗剂总是抑制运动相关的活动。因此，GABA A和B抑制都参与运动控制，在A时产生时相抑制，在B时产生紧张性抑制。此外，将少量激动剂和拮抗剂注入大脑皮层，观察对延迟反应表现的影响。当被注射到前额叶皮质时，对侧手的动作会产生持久性错误，同时会降低操作能力。当注射到运动前皮质时，反应时间变长，而不降低操作效率。运动皮质注射后，运动时间延长，反应时和表现率无明显变化。A抑制倾向于一过性，B抑制倾向于紧张性。因此，GABA抑制被证明与运动和习得行为的控制有关。结果表明，A区和B区的GABA抑制分别参与额叶不同区域的运动和行为控制。

Roles of the GABA inhibition in the controls of behavior or movement were studied in the macaque monkey frontal lobe (the motor cortex, the premotor cortex and the prefrontal cortex). Single neutron activities were recorded from the motor cortex and premotor cortex and GABA_A and GABA_B agonists (Muscimol and Baclofen) and antagonists (Bicuculline and Phaclofen) were applied iontophoretically, while the monkeys were performing a simple visual reaction time task or a visual GO/NO-GO task. Invariably agonists suppressed and antagonists disinhibited movement related activities. Thus, both GABA A and B inhibition is shown to be involved in the movement control, producing phasic inhibition in case of A and tonic inhibition in case of B.Further, small amounts of agonists and antagonists were injected into the cortex and effects on thedelayd response performance were studied. When injected into the prefrontal cortex, perseverative errors were produced in the contralateral hand movements together with lowering the performance. When injected into the premotor cortex, reaction time became longer without lowering the performance rate. And when injected into the motor cortex, movement time became longer with no changes in the reaction time and performance rate. A inhibition tended to be transient and B inhibition tended to be tonic. Thus, GABA inhibition is shown to be involve in the control of movement and learned behavior. It was concluded that the GABA inhibition in both A and B is involved differentially in the control of movement and behavior in different areas of the frontal lobe.