Sensory representations of visual stimuli in the zebrafish brain

Prat Fornsubirà, Ot (2025): Sensory representations of visual stimuli in the zebrafish brain. Dissertation, LMU München: Graduate School of Systemic Neurosciences (GSN)

Abstract

One of the goals of systems neuroscience is that of understanding how nervous systems encode sensory information. Here, we take advantage of larval zebrafish as a model organism in order to investigate sensory representations to two different features of visual stimuli. We first look into the representation of whole-field luminance flashes in the olivocerebellar circuit, and characterize the responses of its different neuronal populations to these simple stimuli. We show that granule cells and inferior olive neurons convey qualitatively distinct information into Purkinje cells, supporting the role attributed to these populations by models of cerebellar function. We also provide proof of the ability of granule cells to hold high-dimensional sensory representations of the environment, and most importantly, of their ability to encode the temporal intervals necessary to allow for cerebellar learning. Finally, we attempt to establish an experimental paradigm to study temporal entrainment of Purkinje cell responses. In the second part of this thesis we focus on the optomotor response, a stabilizing behavior elicited by whole-field motion. First, we perform a series of experiments to characterize the modulation of this behavior by different stimulus features, and show that optomotor behavior is tuned to the temporal frequency of grating stimuli. We also show, however, that not all motor features are equally modulated by this parameter. We then turn to whole-brain imaging experiments in order to try to identify the neural substrates for this motor tuning. We identify motor correlates for temporal frequency tuning in the optic tectum, the torus semicircularis and the pretectum of larval zebrafish, and make an initial attempt at studying differences in the representation of whole-field motion between gratings and more naturalistic stimuli. Altogether, this work deepens our understanding on how visual information is represented in the larval zebrafish brain, and hopefully, contributes on further consolidating this small vertebrate as a prominent model in systems neuroscience.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
• Fakultäten: Graduate School of Systemic Neurosciences (GSN)
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 19. Februar 2025
• 1. Bericht­erstatter:in: Portugues, Ruben