The role of cerebellar circuits in motor adaptation in zebrafish
Final Report Abstract
The cerebellum is a brain region characterised by a relatively simple circuitry, largely preserved across the vertebrate clade, and involved in various tasks. Most notably, the cerebellum has been studied in the context of motor behaviour control. Classic theories of cerebellar function postulate that the coordination of motor responses, as well as the learning of new ones, critically rely on the integration of sensory- and motor-related signals at the level of Purkinje cells. Purkinje cells represent the main output of the cerebellar cortex and integrate information from two different excitatory streams. From one side, each Purkinje cell receives parallel fibre projections from thousands of granule cells that modulate their simple spike rates. From the other, a single strong synapse with a climbing fibre from an inferior olive neuron is established, driving complex spikes. It is believed that by integrating both input streams, the cerebellar cortex encodes the internal models for motor control that should allow for motor adaptation. The present projects aimed at characterising the activity of the different cerebellar populations to sensorimotor behaviours, to understand how information is processed across the olivocerebellar circuit and how these signals can be employed to drive motor adaptation. Our results support classical theories of cerebellar function, showing how the two cerebellar input streams convey qualitatively different information that can potentially encode information necessary to drive cerebellar learning at the Purkinje cell level (project 4). We show that these Purkinje cells can be classified into different subpopulations with distinct functional and morphological properties, matching observations in mammals describing the existence of multiple functional modules dedicated to different sensorimotor behaviours (project 1). Moreover, we also show how these functional groups arise, at least partially, due to the projection patterns of distinct populations within the inferior olive (project 2). Finally, we demonstrate the role of the zebrafish cerebellum as a neuronal substrate for internal models of motor control: we show that while acute modulation of motor behaviour in response to reafference perturbations can be implemented through feedback control loops, the ability of zebrafish to adapt to long-lasting perturbations is cerebellar-dependent (project 3). Altogether, these results deepen our understanding of the sensory information encoded within the olivocerebellar circuit and provide valuable knowledge of how this information is integrated to modulate animal behaviour.
Publications
-
Motor context dominates output from purkinje cell functional regions during reflexive visuomotor behaviours. eLife, 8.
Knogler, Laura D.; Kist, Andreas M. & Portugues, Ruben
-
A cerebellar internal model calibrates a feedback controller involved in sensorimotor control. Nature Communications, 12(1).
Markov, Daniil A.; Petrucco, Luigi; Kist, Andreas M. & Portugues, Ruben
-
Comparing the Representation of a Simple Visual Stimulus across the Cerebellar Network. eneuro, 11(7), ENEURO.0023-24.2024.
Prat, Ot; Petrucco, Luigi; Štih, Vilim & Portugues, Ruben
-
Structural and functional organization of visual responses in the inferior olive of larval zebrafish. The Journal of Neuroscience, e2352212023.
Félix, Rita; Markov, Daniil A.; Renninger, Sabine L.; Tomás, Ana Raquel; Laborde, Alexandre; Carey, Megan R.; Orger, Michael B. & Portugues, Ruben
