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摘要 : 在一个关于作用于纹状体的多巴胺能神经元的重要模型中,多巴胺的相位性释放被认为驱动了基于奖励的学习,而紧张性的多巴胺释放则使系统更偏向于运动(或不运动)。

 在一个关于作用于纹状体的多巴胺能神经元的重要模型中,多巴胺的相位性释放被认为驱动了基于奖励的学习,而紧张性的多巴胺释放则使系统更偏向于运动(或不运动)。Mark Howe 和 Daniel Dombeck发现,小鼠加速运动时,背侧纹状体的多巴胺能轴突内会出现快速相位信号,这种信号还能导致运动加速。他们进而展示,传递运动信号的轴突来自黑质致密部,主要以背侧纹状体为目标,而传递奖励信号的轴突则来自腹侧被盖区,主要以腹侧纹状体为目标。这些发现表明,多巴胺信号能以亚秒精度影响奖励学习和运动,并说明精确的信号时序和神经元类型与治疗多巴胺相关疾病有关 。


Rapid signalling in distinct dopaminergic axons during locomotion and reward


Dopaminergic projection axons from the midbrain to the striatum are crucial for motor control, as their degeneration in Parkinson disease results in profound movement deficits. Paradoxically, most recording methods report rapid phasic dopamine signalling (~100-ms bursts) in response to unpredicted rewards, with little evidence for movement-related signalling. The leading model posits that phasic signalling in striatum-targeting dopamine neurons drives reward-based learning, wheras slow variations in firing (tens of seconds to minutes) in these same neurons bias animals towards or away from movement. However, current methods have provided little evidence to support or refute this model. Here, using new optical recording methods, we report the discovery of rapid phasic signalling in striatum-targeting dopaminergic axons that is associated with, and capable of triggering, locomotion in mice. Axons expressing these signals were largely distinct from those that responded to unexpected rewards. These results suggest that dopaminergic neuromodulation can differentially impact motor control and reward learning with sub-second precision, and indicate that both precise signal timing and neuronal subtype are important parameters to consider in the treatment of dopamine-related disorders.

来源: Nature 浏览次数:1


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