Anatomy and function of retinorecipient arborization fields in zebrafish

Abstract

In 1994, Burrill and Easter described the retinal projections in embryonic and larval zebrafish, introducing the term “arborization fields” (AFs) for the retinorecipient areas. AFs were numbered from 1 to 10 according to their positions along the optic tract. With the exception of AF10 (neuropil of the optic tectum), annotations of AFs remained tentative. Here we offer an update on the likely identities and functions of zebrafish AFs after successfully matching classical neuroanatomy to the digital Max Planck Zebrafish Brain Atlas. In our system, individual AFs are neuropil areas associated with the following nuclei: AF1 with the suprachiasmatic nucleus; AF2 with the posterior parvocellular preoptic nucleus; AF3 and AF4 with the ventrolateral thalamic nucleus; AF4 with the anterior and intermediate thalamic nuclei; AF5 with the dorsal accessory optic nucleus; AF7 with the parvocellular superficial pretectal nucleus; AF8 with the central pretectal nucleus; and AF9d and AF9v with the dorsal and ventral periventricular pretectal nuclei. AF6 is probably part of the accessory optic system. Imaging, ablation, and activation experiments showed contributions of AF5 and potentially AF6 to optokinetic and optomotor reflexes, AF4 to phototaxis, and AF7 to prey detection. AF6, AF8 and AF9v respond to dimming, and AF4 and AF9d to brightening. While few annotations remain tentative, it is apparent that the larval zebrafish visual system is anatomically and functionally continuous with its adult successor and fits the general cyprinid pattern. This study illustrates the synergy created by merging classical neuroanatomy with a cellular‐resolution digital brain atlas resource and functional imaging in larval zebrafish.

Cre-Dependent Anterograde Transsynaptic Labeling and Functional Imaging in Zebrafish Using VSV With Reduced Cytotoxicity

“…In contrast, two Dorsal Thalamus neurons in the same animal (Neuron 2 and Neuron 3) had weak responses to the same visual stimulus ( Figures 3A–A”’ ). This finding is consistent with previous findings that the dorsal thalamus does not respond strongly to moving grating stimuli (Baier and Wullimann, 2021 ). Some animals had neurons with apparent spontaneous calcium activity (3 out of 5 at 5 dpf).…”

“…As the typical visual responsivities of many retinorecipient brain regions are known (Baier and Wullimann, 2021 ), we identified the location of TRAS-M51R labeled retinorecipient neurons using ZBrain, a digital 3D zebrafish brain atlas (Randlett et al, 2015 ). The brain region names (capitalized) are based on the annotations in Zbrain 1.0 1 .…”

Genoarchitecture of the Early Postmitotic Pretectum and the Role of Wnt Signaling in Shaping Pretectal Neurochemical Anatomy in Zebrafish

“…This is because the 48 hpf stage is an early transition stage in which we do not know if the position acquired by each cluster will be the final one in the adult. For this comparative analysis we use available data on the localization of GABAergic, glutamatergic and dopaminergic [tyrosine hydroxylase (TH) -positive)] regions in the larval (48–72 hpf), juvenile and adult zebrafish pretectum ( Mueller et al, 2006 ; Mueller and Guo, 2009 ; Filippi et al, 2014 ; Yáñez et al, 2018 ; Baier and Wullimann, 2021 ).…”

Circuit Organization Underlying Optic Flow Processing in Zebrafish

“…The correspondence between adult pretectal nuclei and optic flow-responsive pretectal neurons in larvae remains unclear. However, a recent study comprehensively matching the function and anatomy between larvae and adults proposed that AF5-pretectal circuits in larvae correspond to the dorsal accessory optic nucleus (DAO) of the adult pretectum ( Baier and Wullimann, 2021 ).…”