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neuroscience, developmental biology, genetics


Deep brain photoreceptors (DBPs) are light sensing neurons present in mammals and non-mammalian vertebrates. In non-mammalian vertebrates, studies have shown DBP involvement in various time and light dependent behaviors including circadian rhythm, phototaxis, and seasonal reproduction. In adult teleosts, DBPs are present throughout the brain, including the optic tectum (OT). While their approximate location in teleosts is known, DBP’s function is relatively unknown. In this study, we focused on DBPs present in the larval zebrafish OT, a multilaminated midbrain structure responsible for multisensory integration. Single-cell RNA sequencing of the larval zebrafish OT showed the presence of several opsins. We focused on opsins that respond in the violet-blue light range - one typical of optogenetic studies. To identify neurons with similar activation patterns following light stimulation, we used live calcium imaging to detect brain activity, followed by watershed segmentation and k-means clustering. Preliminary data comparing the activity patterns following presentation of light stimuli to control and larvae whose eyes have been removed, indicate the presence of two different groups of opsin-responding neurons: one that activates independently of retinal innervation consistent with a DBP identity, and another that activates more frequently when the visual system is intact, suggesting they receive both retinal and DBP inputs. Subsequent studies will include morphological and selective opsins knockout studies to identify DBPs and understand their integration in the microcircuitry and functionality in the OT.

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Life Sciences


Cell Biology and Physiology

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Identifying Deep Brain Photoreceptors in the Larval Zebrafish Optic Tectum

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