Work

Compartmentalized dendritic signaling in a multitasking retinal interneuron

Year: 2017

Type: article

Abstract: The rich diversity of cell types and synaptic motifs in the vertebrate retina provides an excellent platform for uncovering fundamental principles of neural circuit function at the cellular, synaptic, and network levels. In PNAS, Chen et al. (1) report on a remarkable example of compartmentalized dendritic signaling in a retinal neuron despite its small dendritic field. Using two-photon calcium imaging, the authors find that the dendrites of VGluT3-expressing glutamatergic amacrine cells (GACs), which diffusely ramify in the inner plexiform layer (IPL) of the mouse retina, exhibit depth-dependent activation at light onset and offset in dendritic subregions that matches the general scheme of ON/OFF segregation in the IPL. Distinct patterns of local dendritic activation occur within a mere depth of ∼30 μm in the middle of the IPL, arising from highly localized excitatory inputs that are compartmentalized by synaptic inhibition. Chen et al.’s findings extend our mechanistic understanding of the functional segregation of ON/OFF visual channels at the level of dendritic subdomains. Early in the visual pathway, bright and dark contrasts in the visual scene are separately processed by ON and OFF channels. This segregation first occurs in the IPL (2⇓–4), the second synaptic layer of the retina that harbors neuronal processes of over 70 types of bipolar cells, amacrine cells, and retinal ganglion cells (5, 6). While the plethora of cell types are intricately connected to form multiple circuits that extract a variety of visual features in parallel, they are anatomically partitioned into the inner ON sublayer and the outer OFF sublayer of the IPL. ON bipolar cells terminate their axons in the ON sublayer and release more glutamate at light onset, while OFF bipolar cell axons occupy the OFF sublayer and release more glutamate at light offset (Fig. 1). The amacrine and retinal ganglion cells … [↵][1]1Email: weiw{at}uchicago.edu. [1]: #xref-corresp-1-1

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.1715503114

Author: Wei Wei

Institution: University of Chicago

Language: English

Topic: Neuroscience and Neuropharmacology Research

Subfield: Cellular and Molecular Neuroscience

Field: Neuroscience

Domain: Life Sciences

Open Access status: green

Funders: McKnight Foundation, National Eye Institute

Awards: G2776841772, Synaptic basis of motion detection in the retina