Comoli Eliane, Coizet Véronique, Boyes Justin, Bolam J Paul, Canteras Newton S, Quirk Rachel H, Overton Paul G, Redgrave Peter
Department of Psychology, University of Sheffield, Sheffield S10 2TP, UK.
Nat Neurosci. 2003 Sep;6(9):974-80. doi: 10.1038/nn1113.
Midbrain dopaminergic neurons respond to unexpected and biologically salient events, but little is known about the sensory systems underlying this response. Here we describe, in the rat, a direct projection from a primary visual structure, the midbrain superior colliculus (SC), to the substantia nigra pars compacta (SNc) where direct synaptic contacts are made with both dopaminergic and non-dopaminergic neurons. Complementary electrophysiological data reveal that short-latency visual responses in the SNc are abolished by ipsilateral lesions of the SC and increased by local collicular stimulation. These results show that the tectonigral projection is ideally located to relay short-latency visual information to dopamine-containing regions of the ventral midbrain. We conclude that it is within this afferent sensory circuitry that the critical perceptual discriminations that identify stimuli as both unpredicted and biologically salient are made.
中脑多巴胺能神经元对意外且具有生物学显著性的事件做出反应，但对于这种反应背后的感觉系统却知之甚少。在此，我们描述了大鼠中从一个主要视觉结构——中脑上丘（SC）到黑质致密部（SNc）的直接投射，在SNc中与多巴胺能和非多巴胺能神经元都形成了直接的突触联系。补充的电生理数据表明，SNc中的短潜伏期视觉反应会因同侧SC损伤而消失，并因局部丘刺激而增强。这些结果表明，顶盖黑质投射的位置非常理想，能够将短潜伏期视觉信息传递到腹侧中脑的含多巴胺区域。我们得出结论，正是在这种传入感觉回路中，做出了将刺激识别为既不可预测又具有生物学显著性的关键知觉辨别。
