Reciprocal synapses between mushroom body and dopamine neurons form a positive feedback loop required for learning

eLife

Ronald L Davis¹  Molee Chakraborty¹  Anna Phan¹  Isaac Cervantes-Sandoval¹ 

[1] Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, United States;

关键词: learning and memory;    reciprocal connectivity;    dopaminergic neurons;    mushroom body;    recurrent circuit;   

DOI  :  10.7554/eLife.23789

来源: DOAJ

【 摘 要 】

Current thought envisions dopamine neurons conveying the reinforcing effect of the unconditioned stimulus during associative learning to the axons of Drosophila mushroom body Kenyon cells for normal olfactory learning. Here, we show using functional GFP reconstitution experiments that Kenyon cells and dopamine neurons from axoaxonic reciprocal synapses. The dopamine neurons receive cholinergic input via nicotinic acetylcholine receptors from the Kenyon cells; knocking down these receptors impairs olfactory learning revealing the importance of these receptors at the synapse. Blocking the synaptic output of Kenyon cells during olfactory conditioning reduces presynaptic calcium transients in dopamine neurons, a finding consistent with reciprocal communication. Moreover, silencing Kenyon cells decreases the normal chronic activity of the dopamine neurons. Our results reveal a new and critical role for positive feedback onto dopamine neurons through reciprocal connections with Kenyon cells for normal olfactory learning.

【 授权许可】

Unknown