目的:嗅球(OB)中的神经活动可以代表不同大脑和行为状态下的气味信息。例如,在学习气味识别任务期间,OB中二尖瓣/簇绒(M/T)细胞的气味反应发生变化,在网络层面,在此类任务中的气味呈现期间,β功率增加并且高伽马(HG)功率降低。然而,这些观察结果背后的神经机制仍然知之甚少。这里,我们研究了从背中缝核(DRN)到OB的5-羟色胺能调节是否参与小鼠的去/去任务学习过程中的塑造活动。
方法:纤维光度法用于记录进行/不进行任务期间DRN血清素能神经元的种群活动。在进行/不进行任务期间,体内电生理学用于记录OB中的神经活动(单个单位和局部场电位)。使用特定子区域(iClass)测试中的实时位置偏好(RTPP)和颅内光施用来评估小鼠编码奖励信息的能力。
结果:DRN中5-羟色胺能神经元中气味诱发的群体活动是在进行/不进行任务的学习过程中形成的。在OB中,从振荡到单细胞的神经活动表现出复杂的,在气味辨别任务期间,与学习相关的变化和编码信息的能力。然而,消融DRN5-羟色胺能神经元后未观察到这些特性.
结论:OB中神经网络和单细胞的活性,以及它们编码气味值信息的能力,由DRN的血清素能投射形成。
OBJECTIVE: Neural activity in the olfactory bulb (OB) can represent odor information during different brain and behavioral states. For example, the odor responses of mitral/tufted (M/T) cells in the OB change during learning of odor-discrimination tasks and, at the network level, beta power increases and the high gamma (HG) power decreases during odor presentation in such tasks. However, the neural mechanisms underlying these observations remain poorly understood. Here, we investigate whether serotonergic modulation from the dorsal raphe nucleus (DRN) to the OB is involved in shaping activity during the learning process in a go/no-go task in mice.
METHODS: Fiber photometry was used to record the population activity of DRN serotonergic neurons during a go/no-go task. In vivo electrophysiology was used to record neural activity (single units and local field potentials) in the OB during the go/no-go task. Real-time place preference (RTPP) and intracranial light administration in a specific subarea (iClass) tests were used to assess the ability of mice to encoding reward information.
RESULTS: Odor-evoked population activity in serotonergic neurons in the DRN was shaped during the learning process in a go/no-go task. In the OB, neural activity from oscillations to single cells showed complex, learning-associated changes and ability to encode information during an odor discrimination task. However, these properties were not observed after ablation of DRN serotonergic neurons.
CONCLUSIONS: The activity of neural networks and single cells in the OB, and their ability to encode information about odor value, are shaped by serotonergic projections from the DRN.