MIBE Seminar: Preoptic Area and Dorsal Habenula Jointly Support Homeostatic Navigation in Larval Zebrafish

Topic: Preoptic Area and Dorsal Habenula Jointly Support Homeostatic Navigation in Larval Zebrafish

Speaker: Virginia Palieri, Doctoral Candidate (Portugues Group)

Date and Time: Tuesday, 25 April 2023, 1:00 pm

Abstract: To prevent damage, animals must maintain physiological processes within an optimal range, despite environmental perturbations. One prime example is thermoregulation. Homeotherms like mammals and birds can couple autonomic measures like shivering/sweating with behavioral strategies. On the contrary, ectotherms, such as fish, amphibians, reptiles and the vast majority of invertebrates need to move, to navigate toward places where the external temperature matches their homeostatic setpoint (i.e. homeostatic navigation). We investigated the importance of sensory history and previous motor choices in shaping structured, coherent trajectories essential for preventing thermal stress in small ectotherms, like larval zebrafish, when they are pushed away from their homeostatic setpoint. We employed whole-brain functional imaging, targeted chemogenetic and laser ablations in larval zebrafish to show that evolutionarily conserved pathways have been repurposed in a species-specific manner to drive different aspects of homeostatic navigation.
On one hand, the Preoptic Area (PoA), a part of the hypothalamus, involved in controlling core body temperature in mammals, acts like a thermostat switching the fish behavioral strategy in a non-directional manner integrating the immediate sensory evidence. The Habenula-Interpeduncular nucleus-Raphe circuit, on the other hand, supports the PoA by storing a longer memory of the stimulus changes and driving coherent trajectories.