Goldberg Jesse H, Fee Michale S
McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
J Neurophysiol. 2010 Apr;103(4):2002-14. doi: 10.1152/jn.01038.2009. Epub 2010 Jan 27.
The striatum-the primary input nucleus of the basal ganglia-plays a major role in motor control and learning. Four main classes of striatal neuron are thought to be essential for normal striatal function: medium spiny neurons, fast-spiking interneurons, cholinergic tonically active neurons, and low-threshold spiking interneurons. However, the nature of the interaction of these neurons during behavior is poorly understood. The songbird area X is a specialized striato-pallidal basal ganglia nucleus that contains two pallidal cell types as well as the same four cell types found in the mammalian striatum. We recorded 185 single units in Area X of singing juvenile birds and, based on singing-related firing patterns and spike waveforms, find six distinct cell classes--two classes of putative pallidal neuron that exhibited a high spontaneous firing rate (> 60 Hz), and four cell classes that exhibited low spontaneous firing rates characteristic of striatal neurons. In this study, we examine in detail the four putative striatal cell classes. Type-1 neurons were the most frequently encountered and exhibited sparse temporally precise singing-related activity. Type-2 neurons were distinguished by their narrow spike waveforms and exhibited brief, high-frequency bursts during singing. Type-3 neurons were tonically active and did not burst, whereas type-4 neurons were inactive outside of singing and during singing generated long high-frequency bursts that could reach firing rates over 1 kHz. Based on comparison to the mammalian literature, we suggest that these four putative striatal cell classes correspond, respectively, to the medium spiny neurons, fast-spiking interneurons, tonically active neurons, and low-threshold spiking interneurons that are known to reside in area X.
纹状体——基底神经节的主要输入核团——在运动控制和学习中起主要作用。纹状体神经元主要分为四类，一般认为它们对正常的纹状体功能至关重要：中型多棘神经元、快速放电中间神经元、胆碱能紧张性活动神经元和低阈值放电中间神经元。然而，这些神经元在行为过程中的相互作用本质却鲜为人知。鸣禽的X区是一个特殊的纹状体 - 苍白球基底神经节核团，其中包含两种苍白球细胞类型以及与哺乳动物纹状体中相同的四种细胞类型。我们记录了正在鸣叫的幼鸟X区的185个单个神经元，基于与鸣叫相关的放电模式和尖峰波形，发现了六种不同的细胞类型——两类假定的苍白球神经元，其自发放电率较高（> 60 Hz），以及四类细胞类型，其自发放电率较低，具有纹状体神经元的特征。在本研究中，我们详细研究了四类假定的纹状体细胞类型。1型神经元是最常见的，表现出稀疏的、时间精确的与鸣叫相关的活动。2型神经元的特征是其尖峰波形狭窄，在鸣叫期间表现出短暂的高频爆发。3型神经元是紧张性活动的，不会爆发，而4型神经元在鸣叫之外不活动，在鸣叫期间产生长的高频爆发，其放电率可达1 kHz以上。基于与哺乳动物文献的比较，我们认为这四类假定的纹状体细胞类型分别对应于已知存在于X区的中型多棘神经元、快速放电中间神经元、紧张性活动神经元和低阈值放电中间神经元。
