Pinaud Raphael, Mello Claudio V
Laboratory of Auditory and Vocal Learning, Neurological Sciences Institute, Oregon Health and Sciences University, Portland, OR, USA.
J Chem Neuroanat. 2007 Sep;34(1-2):1-21. doi: 10.1016/j.jchemneu.2007.03.005. Epub 2007 Mar 27.
Inhibitory transmission is critical to sensory and motor processing and is believed to play a role in experience-dependent plasticity. The main inhibitory neurotransmitter in vertebrates, GABA, has been implicated in both sensory and motor aspects of vocalizations in songbirds. To understand the role of GABAergic mechanisms in vocal communication, GABAergic elements must be characterized fully. Hence, we investigated GABA immunohistochemistry in the zebra finch brain, emphasizing auditory areas and song control nuclei. Several nuclei of the ascending auditory pathway showed a moderate to high density of GABAergic neurons including the cochlear nuclei, nucleus laminaris, superior olivary nucleus, mesencephalic nucleus lateralis pars dorsalis, and nucleus ovoidalis. Telencephalic auditory areas, including field L subfields L1, L2a and L3, as well as the caudomedial nidopallium (NCM) and mesopallium (CMM), contained GABAergic cells at particularly high densities. Considerable GABA labeling was also seen in the shelf area of caudodorsal nidopallium, and the cup area in the arcopallium, as well as in area X, the lateral magnocellular nucleus of the anterior nidopallium, the robust nucleus of the arcopallium and nidopallial nucleus HVC. GABAergic cells were typically small, most likely local inhibitory interneurons, although large GABA-positive cells that were sparsely distributed were also identified. GABA-positive neurites and puncta were identified in most nuclei of the ascending auditory pathway and in song control nuclei. Our data are in accordance with a prominent role of GABAergic mechanisms in regulating the neural circuits involved in song perceptual processing, motor production, and vocal learning in songbirds.
抑制性传递对于感觉和运动处理至关重要，并且被认为在依赖经验的可塑性中发挥作用。脊椎动物中的主要抑制性神经递质γ-氨基丁酸（GABA），已被证明与鸣禽发声的感觉和运动方面都有关联。为了了解GABA能机制在发声交流中的作用，必须对GABA能成分进行全面表征。因此，我们研究了斑胸草雀脑中的GABA免疫组织化学，重点关注听觉区域和发声控制核团。听觉上行通路的几个核团显示出中度到高密度的GABA能神经元，包括耳蜗核、层状核、上橄榄核、中脑外侧核背侧部和卵圆核。端脑听觉区域，包括L区的L1、L2a和L3亚区，以及尾内侧巢皮质（NCM）和中皮质（CMM），含有特别高密度的GABA能细胞。在尾背侧巢皮质的边缘区域、弓状皮质的杯状区域，以及X区、前巢皮质的外侧大细胞核、弓状皮质的粗壮核和巢皮质核HVC中也观察到大量的GABA标记。GABA能细胞通常较小，很可能是局部抑制性中间神经元，不过也识别出了稀疏分布的大型GABA阳性细胞。在听觉上行通路的大多数核团和发声控制核团中都识别出了GABA阳性神经突和点状结构。我们的数据表明，GABA能机制在调节参与鸣禽歌声感知处理、运动产生和发声学习的神经回路中起着重要作用。
