PUBLICATION
Functional, molecular and morphological heterogeneity of superficial interneurons in the larval zebrafish tectum
- Authors
- Barker, A.J., Helmbrecht, T.O., Grob, A.A., Baier, H.
- ID
- ZDB-PUB-201208-42
- Date
- 2020
- Source
- The Journal of comparative neurology 529(9): 2159-2175 (Journal)
- Registered Authors
- Baier, Herwig
- Keywords
- cell type, interneurons, luminance detection, optic tectum, zebrafish
- MeSH Terms
-
- Animals
- Animals, Genetically Modified
- Interneurons/chemistry
- Interneurons/physiology*
- Photic Stimulation/methods*
- Superior Colliculi/chemistry
- Superior Colliculi/cytology*
- Superior Colliculi/physiology*
- Visual Perception/physiology*
- Zebrafish
- PubMed
- 33278028 Full text @ J. Comp. Neurol.
Citation
Barker, A.J., Helmbrecht, T.O., Grob, A.A., Baier, H. (2020) Functional, molecular and morphological heterogeneity of superficial interneurons in the larval zebrafish tectum. The Journal of comparative neurology. 529(9):2159-2175.
Abstract
The superficial interneurons, SINs, of the zebrafish tectum, have been implicated in a range of visual functions, including size discrimination, directional selectivity and looming-evoked escape. This raises the question if SIN subpopulations, despite their morphological similarities and shared anatomical position in the retinotectal processing stream, carry out diverse, task-specific functions in visual processing, or if they have simple tuning properties in common. Here we have further characterized the SINs through functional imaging, electrophysiological recordings and neurotransmitter typing in two transgenic lines, the widely used Gal4s1156t and the recently reported LCRRH2-RH2-2:GFP. We found that about a third of the SINs strongly responded to changes in whole-field light levels, with a strong preference for OFF over ON stimuli. Interestingly, individual SINs were selectively tuned to a diverse range of narrow luminance decrements. Overall responses to whole-field luminance steps did not vary with the position of the SIN cell body along the depth of the tectal neuropil or with the orientation of its neurites. We ruled out the possibility that intrinsic photosensitivity of Gal4s1156t+ SINs contribute to the measured visual responses. We found that, while most SINs express GABAergic markers, a substantial minority express an excitatory neuronal marker, the vesicular glutamate transporter, expanding the possible roles of SIN function in the tectal circuitry. In conclusion, SINs represent a molecularly, morphologically and functionally heterogeneous class of interneurons, with subpopulations that detect a range of specific visual features, to which we have now added narrow luminance decrements. This article is protected by copyright. All rights reserved.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping