科学研究

学术报告

鱼真的是7秒记忆吗?斑马鱼的大脑状态和记忆

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2019-06-11

     



Seminar Type

A-Type

Preferred Location

Third Floor Lecture Hall, Jianzan Building(Phase I)

Chinese Institute for Brain Research, Beijing

Time

14:00-15:00 pm  

Wednesday, Jun 19, 2019

Speaker

Misha B. Ahrens, PhD

Janelia Group Leader,

Janelia Research Campus, Howard Hughes Medical Institute

Host

Minmin Luo

Topic

Brain states and memory in zebrafish

Abstract

As animals navigate complex environments, their reactions to identical stimuli can change according to their recent experience. Such changing behavioral states gives rise to flexibility in behavior beneficial to survival. We investigated the mechanistic origins of three such behavioral states, which depended on whether animals experienced (1) successful outcomes of actions, (2) unsuccessful outcomes of actions, (3) sensory input during inactivity. We found that actions (swimming) with successful outcomes (visual flow) are encoded by the serotonergic system, lead to motor learning, and are detected by a gating mechanism in individual serotonergic neurons based on rebound from hyperpolarization. On the other hand, actions with unsuccessful outcomes (swimming that does not trigger visual flow) are encoded by the noradrenergic system, integrated by astrocytes, and eventually trigger a passive behavioral state. Finally, sensory signals that enter the brain before actions drive a memory in a network of inhibitory brainstem neurons which set an alertness state that determines reaction time to future sensory input. Thus, sensory input is ‘routed’ to distinct neuromodulatory systems depending on its temporal relationship to actions, each leading to distinct behavioral states. This work suggests action-timing-dependent routing of sensory signals to different neuromodulatory centers as one of the principles for how an animal’s past experience determines its future behavior

Speaker Biography

Misha Ahrens joined Janelia in the fall of 2012, researching systems neuroscience in zebrafish. He completed his BA in mathematics and physics at Cambridge University, and his PhD in computational neuroscience at the Gatsby Computational Neuroscience Unit, at University College London. From 2009 to 2012 he was a Sir Henry Wellcome Postdoctoral Fellow, working in the Engert Lab, at Harvard University.