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

在猕猴额叶（运动皮层、前运动皮层和前额叶皮层）研究了GABA抑制在行为或运动控制中的作用。记录运动皮层和前运动皮层的单中子活动，并通过电离子透入的方式应用GABA_A和GABA_B激动剂（蝇蕈醇和巴氯芬）和拮抗剂（荷包牡丹碱和法氯芬），同时进行简单的视觉反应时任务或视觉GO/NO-GO任务。激动剂总是抑制运动相关活动，而拮抗剂总是解除运动相关活动。因此，GABA A和B抑制都参与了运动控制，在A的情况下产生阶段性抑制，在B的情况下产生紧张性抑制。当注射到前额叶皮层时，在对侧手部动作中产生持续错误，同时降低操作成绩。当注射到前运动皮层时，反应时间变得更长，而不降低执行速度。当注射到运动皮质时，运动时间变得更长，而反应时间和表现速度没有变化。A抑制往往是短暂的，B抑制往往是紧张性的。因此，GABA抑制被证明参与运动和学习行为的控制。结果表明，GABA在A和B区的抑制作用与额叶不同区域的运动和行为控制有关。

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.