A Central Role for Mixed Acetylcholine/GABA Transmission in Direction Coding in the Retina

作者：Sethuramanujam Santhosh; McLaughlin Amanda J; Derosenroll Geoffery; Hoggarth Alex; Schwab David J; Awatramani Gautam B^*

来源：Neuron, 2016, 90(6): 1243-1256.

DOI：10.1016/j.neuron.2016.04.041

A surprisingly large number of neurons throughout the brain are endowed with the ability to co-release both a fast excitatory and inhibitory transmitter. The computational benefits of dual transmitter release, however, remain poorly understood. Here, we address the role of co-transmission of acetylcholine (ACh) and GABA from starburst amacrine cells (SACs) to direction-selective ganglion cells (DSGCs). Using a combination of pharmacology, optogenetics, and linear regression methods, we estimated the spatiotemporal profiles of GABA, ACh, and glutamate receptor-mediated synaptic activity in DSGCs evoked by motion. We found that ACh initiates responses to motion in natural scenes or under low-contrast conditions. In contrast, classical glutamatergic pathways play a secondary role, amplifying cholinergic responses via NMDA receptor activation. Furthermore, under these conditions, the network of SACs differentially transmits ACh and GABA to DSGCs in a directional manner. Thus, mixed transmission plays a central role in shaping directional responses of DSGCs.

• 出版日期2016-6-15
• 单位西北大学