Role of the basal ganglia in learning and initiation of purposeful behavior

为了了解基底神经节神经元在行为学习过程中和之后表达获得性活动的机制，在记录执行行为任务的猴子纹状体神经元活动的同时，使用了选择性多巴胺(DA)受体拮抗剂。在实验1中，一只猴子被训练将滴答声与一滴奖励水联系起来。DA受体拮抗剂用不锈钢注射管(i.d.300um)微压给药，用特氟龙包裹的记录神经元活动的钨丝穿过该管子。在使用D_1或D_2类DA受体拮抗剂(总体积和1MU_1，以1MU_1/5~10分钟的速率)时，用钨丝电极记录了灵长类纹状体的一类神经元--紧张性活动神经元(TAN)对声音的反应。应用D2类拮抗剂(-)-舒必利(20微克/毫升，58 mM，pH 6.8)，5个被测的坦坦中有4个的反应被取消。在另外5个TNA中，n…D2类拮抗剂和D1类拮抗剂SCH23390(10mug/mul，31 mM，pH5.7)和顺式氟苯硫醇(30mug/mul，59 mM，pH6.6)均显著抑制上述反应。在实验2中，将四个或五个桶形玻璃微电极插入纹状体。中央桶用于细胞外记录TANS的活性。每个DA受体拮抗剂都通过周围的一个桶进行离子电泳法应用。使用SCH23390(10 mM，p H4.5)和(-)-舒必利(10 mM，p H4.5)。在40例TAN中观察了D_1和D_2类拮抗剂的离子导入效应。在记录的40个TAN中，19个TAN完全被D2类拮抗剂抑制，3个TAN完全被D1类拮抗剂抑制，7个TAN同时被D1类和D2类拮抗剂抑制。以加压(~lt；1µl)或离子导入(~lt；30nA)加生理盐水的0.9%氯化钠溶液为对照，无论是背景放电还是对TANS的反应都没有明显的影响。D1或D2类拮抗剂的背景放电速率也不受微压注射或离子导入的影响。结果表明，黑质纹状体多巴胺系统使TANS主要通过纹状体中的D2类受体和部分D2类受体介导的机制表达习得性活动。较少

To understand the mechanisms by which basal ganglia neurons express acquired activities during and after behavioral learning, selective dopamine (DA) receptor antagonists were applied while recording the activity of striatal neurons in monkeys performing hehavioral tasks. In experiment 1, a monkey was trained to associate a click sound with a drop of reward water. DA receptor antagonists were administered by micropressure using a stainless steel injection cannula (i.d.300mum) through which a teflon-coated tungsten wire for recording neuronal activity had been threaded. Responses to sound by tonically active neurons (TANs), a class of neurons in the primate striatum, were recorded through a tungsten wire electrode during the application of either D1- or D2-class DA receptor antagonists (total volume<1 mu1, at a rate of 1 mu1/5-10 min). Application of the D2-class antagonist, (-) -sulpiride (20mug/mul, 58mM,pH6.8), abolished the responses of 4 out of 5 TANs examined. In another 5 TNAs, n … More either the D2-class antagonist nor the D1-class antagonists, SCH23390 (10mug/mul, 31mM,pH5.7) or cis-flupenthixol (30mug/mul, 59mM,pH6.6) significantly suppressed responses. In experiment2, four-or five-barreled glass microelectrodes were inserted into the striatum. The central barrel was used for extracellular recording of activity of TANs. Each DA receptor antagonist was iontophoretically applied through one of the surrounding barrels. SCH23390 (10mM,pH4.5) and (-) -sulpiride (10mM,pH4.5) were used. The effects of iontophoresis of both D1-and D2-class antagonists were examined in 40 TANs. Out of 40 TANs from which recording were made, responses were suppressed exclusively by the D2-class antagonist in 19 TANs, exclusively by the D1-class antagonist in 3 TANs, and by both D1- and D2-class antagonists in 7 TANs. When 0.9% NaCl, saline, was applied by pressure (<1mul) or by iontophoresis (<30nA) as a control, neither the background discharge rates nor the responses of TANs were significantly influenced. Background discharge rate of TANs was also not affected by D1- or D2-class antagonists applied by either micropressure injection or iontophoresis. It was concluded that the nigrostriatal dopamine system enables TANs to express learned activity primarily through D2-class and partly through D1-class receptor-mediated mechanisms in the striatum. Less