Department of Psychology and Neuroscience, Duke University, Durham, North Carolina, United States of America.
PLoS One. 2013 Aug 6;8(8):e71598. doi: 10.1371/journal.pone.0071598. Print 2013.
A major output nucleus of the basal ganglia is the substantia nigra pars reticulata, which sends GABAergic projections to brainstem and thalamic nuclei. The GABAergic (GABA) neurons are reciprocally connected with nearby dopaminergic neurons, which project mainly to the basal ganglia, a set of subcortical nuclei critical for goal-directed behaviors. Here we examined the impact of motivational states on the activity of GABA neurons in the substantia nigra pars reticulata and the neighboring dopaminergic (DA) neurons in the pars compacta. Both types of neurons show short-latency bursts to a cue predicting a food reward. As mice became sated by repeated consumption of food pellets, one class of neurons reduced cue-elicited firing, whereas another class of neurons progressively increased firing. Extinction or pre-feeding just before the test session dramatically reduced the phasic responses and their motivational modulation. These results suggest that signals related to the current motivational state bidirectionally modulate behavior and the magnitude of phasic response of both DA and GABA neurons in the substantia nigra.
基底神经节的一个主要输出核团是黑质网状部，它向脑干和丘脑核团发出 GABA 能投射。GABA 能神经元与附近的多巴胺能神经元相互连接，多巴胺能神经元主要投射到基底神经节，基底神经节是一组对目标导向行为至关重要的皮质下核团。在这里，我们研究了动机状态对黑质网状部 GABA 能神经元和相邻致密部多巴胺能（DA）神经元活性的影响。这两种类型的神经元对预测食物奖励的线索都表现出短潜伏期爆发。当老鼠通过反复食用食物丸而感到饱足时，一类神经元减少了线索诱发的放电，而另一类神经元则逐渐增加了放电。在测试前进行消退或预喂食会显著降低相位反应及其动机调节。这些结果表明，与当前动机状态相关的信号双向调节行为以及黑质中 DA 和 GABA 神经元的相位反应幅度。
