Functional Compartmentalization within Starburst Amacrine Cell Dendrites in the Retina

• Published in: Cell reports (Cambridge) Vol. 22; no. 11; pp. 2898 - 2908
• Main Authors: Poleg-Polsky, Alon, Ding, Huayu, Diamond, Jeffrey S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 13.03.2018; Elsevier
• Subjects: amacrine cell; Amacrine Cells - metabolism; Animals; correlation; Dendrites - physiology; direction selectivity; Disease Models, Animal; Humans; inhibition; Mice; retina; Retina - physiology; synaptic transmission; Visual Pathways - physiology; visual processing; amacrine cell; direction selectivity; correlation; retina; visual processing; inhibition; synaptic transmission
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2018.02.064

Dendrites in many neurons actively compute information. In retinal starburst amacrine cells, transformations from synaptic input to output occur within individual dendrites and mediate direction selectivity, but directional signal fidelity at individual synaptic outputs and correlated activity among neighboring outputs on starburst dendrites have not been examined systematically. Here, we record visually evoked calcium signals simultaneously at many individual synaptic outputs within single starburst amacrine cells in mouse retina. We measure visual receptive fields of individual output synapses and show that small groups of outputs are functionally compartmentalized within starburst dendrites, creating distinct computational units. Inhibition enhances compartmentalization and directional tuning of individual outputs but also decreases the signal-to-noise ratio. Simulations suggest, however, that the noise underlying output signal variability is well tolerated by postsynaptic direction-selective ganglion cells, which integrate convergent inputs to acquire reliable directional information. [Display omitted] •Visual responses of many individual synapses were measured simultaneously•SAC dendrites contain many functionally distinct clusters of output synapses•Inhibition enhances dendritic compartmentalization and directional tuning•SAC signaling noise is well tolerated via postsynaptic integration in DSGCs Poleg-Polsky et al. examine the directional signaling fidelity of individual synapses on starburst amacrine cell dendrites. They identify functionally and morphologically distinct signaling compartments within SAC dendrites and show that inhibition enhances reliable decoding by postsynaptic direction-selective ganglion cells.