Prof. Emre Yaksi, NTNU
Prof. Emre Yaksi, from the Kavli Institute for Systems Neuroscience at NTNU, will present: " Searching for Evolutionary Traces of Vertebrate Thalamo-Cortical Systems in the Zebrafish Brain"
Main content
In vertebrates, cortical regions are defined by distinct thalamic innervations that carry sensory and cortico-thalamic information. The zebrafish telencephalon, considered an ancestral homolog of the vertebrate cortex, supports complex behaviors like navigation and social interactions. How the zebrafish telencephalon receives and processes sensory information, and how these processes relate to other vertebrate cortices, remains unclear.Through anatomical tracing, electrophysiological circuit mapping, calcium imaging, and comparative transcriptomics, we characterized thalamocortical systems in zebrafish. We found that the preglomerular nucleus (PG) is the primary source of visual and auditory inputs to the telencephalon. We demonstrated that PG neurons and their axonal innervations in the telencephalon exhibit topographically organized, sensory-specific responses. In contrast, the sensory responses of telencephalic neurons reveal multiple layers of topographically organized hierarchies, from simple sensory-specific responses to multi-modal and coincidence-detecting non-linear responses.Overall, we observed an increasing complexity in the hierarchy of telecehalic sensory computations, which is topographically organized into distinct nuclei from posterior to anterior. We mapped these individual nuclei to distinct cortico-limbic cell types in other vertebrates, showing that zebrafish telencephalic neurons analogous to the vertebrate neocortex are at the top of the sensory computation hierarchy. We are currently further investigating the role of these neocortex-like neurons in relaying telencephalic computations to the rest of the brain.
