Computational and Molecular Properties of Starburst Amacrine Cell Synapses Differ With Postsynaptic Cell Type

Frontiers in Cellular Neuroscience

Joshua H. Singer¹  Joseph Pottackal¹  Jonathan B. Demb³ 

[1] Department of Biology, University of Maryland, College Park, College Park, MD, United States;Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States;Department of Neuroscience, Yale University, New Haven, CT, United States;Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, United States;Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States;

关键词: GABA;    interneurons;    neural circuits;    optogenetics;    parallel processing;    retina;   

DOI  :  10.3389/fncel.2021.660773

来源: DOAJ

【 摘 要 】

A presynaptic neuron can increase its computational capacity by transmitting functionally distinct signals to each of its postsynaptic cell types. To determine whether such computational specialization occurs over fine spatial scales within a neurite arbor, we investigated computation at output synapses of the starburst amacrine cell (SAC), a critical component of the classical direction-selective (DS) circuit in the retina. The SAC is a non-spiking interneuron that co-releases GABA and acetylcholine and forms closely spaced (<5 μm) inhibitory synapses onto two postsynaptic cell types: DS ganglion cells (DSGCs) and neighboring SACs. During dynamic optogenetic stimulation of SACs in mouse retina, whole-cell recordings of inhibitory postsynaptic currents revealed that GABAergic synapses onto DSGCs exhibit stronger low-pass filtering than those onto neighboring SACs. Computational analyses suggest that this filtering difference can be explained primarily by presynaptic properties, rather than those of the postsynaptic cells per se. Consistent with functionally diverse SAC presynapses, blockade of N-type voltage-gated calcium channels abolished GABAergic currents in SACs but only moderately reduced GABAergic and cholinergic currents in DSGCs. These results jointly demonstrate how specialization of synaptic outputs could enhance parallel processing in a compact interneuron over fine spatial scales. Moreover, the distinct transmission kinetics of GABAergic SAC synapses are poised to support the functional diversity of inhibition within DS circuitry.

【 授权许可】

Unknown