An uncommon neuronal class conveys visual signals from rods and cones to retinal ganglion cells

Abstract

Neurons in the central nervous system (CNS) are distinguished by the neurotransmitter types they release, their synaptic connections, morphology, and genetic profiles. To fully understand how the CNS works, it is critical to identify all neuronal classes and reveal their synaptic connections. The retina has been extensively used to study neuronal development and circuit formation. Here, we describe a previously unidentified interneuron in mammalian retina. This interneuron shares some morphological, physiological, and molecular features with retinal bipolar cells, such as receiving input from photoreceptors and relaying visual signals to retinal ganglion cells. It also shares some features with amacrine cells (ACs), particularly Aii-ACs, such as their neurite morphology in the inner plexiform layer, the expression of some AC-specific markers, and possibly the release of the inhibitory neurotransmitter glycine. Thus, we unveil an uncommon interneuron, which may play an atypical role in vision.

Longitudinal in vivo Ca 2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level

“…For example, the long-lasting elevation of intracellular calcium after offset of the stimulating light in ON-Sust1 cells ( Fig. 2 A ) may not precisely reflect neuronal activities, although a newly identified retinal interneuron, the Campana cell, also presents prolonged Ca 2+ responses (30 s) after very short light stimulation (10 ms) ( 70 ). The reliability and precision of in vivo RGC neuronal activities need conclusive confirmation by in vivo study of RGC electrophysiology, applying techniques such as epiretinal-implantable MEA ( 25 , 71 ).…”

Developmental errors in the common marmoset retina

“…To our knowledge, there are no reports about other misplaced glycinergic ACs (mGlyACs); recently, however, a new type of interneuron has been described in mouse and primate retina. The so-called Campana cells share some features with BCs, such as receiving input from photoreceptors and relaying visual signals to RGCs, but also share some features with AII ACs, such as their dendritic morphology in the IPL and the expression of GlyT1 (Young et al, 2021 ). By reproducing their results with our marmoset tissue ( n = 5, Table 2 ), we not only saw glycinergic ACs with ascending dendrites into the OPL ( Figure 4A , arrowheads), but also readily found mGlyACs with somata in the OPL ( Figures 4B , F ) or outer INL ( Figure 4D ).…”

Modeling the Effects of Napping and Non-napping Patterns of Light Exposure on the Human Circadian Oscillator

“…Furthermore, ipRGCs in mice have been categorized into five types, referred to as M1-M5 (Viney et al, 2007) with each type exhibiting differences in their properties, such as intrinsic photosensitivity and firing rate, and their functions, such as circadian photoentrainment and detecting motion (Ecker et al, 2010; Hu et al, 2013; Zhao et al, 2014). New uncharacterized cell types in the retina are still being discovered (Quattrochi et al, 2019; Young et al, 2021), and the influence of the wavelength of light may be unique for different types of photoreceptors (Berson et al, 2002; Lall et al, 2010; Lucas et al, 2014).…”