Dissertation

Identification of Neural Premotor Substrates Affecting Nocifensive Behaviour in Drosophila Larvae

Garner, Alastair

2020

Overview

The locomotor repertoire of an individual can encompass a range of distinct motor patterns, all of which are encoded and coordinated by the nervous system. Despite diversity in these behaviours, each locomotor mode is enabled by a limited, common musculature. How neural circuits are organised to facilitate discrete patterns of locomotion is not well understood. Drosophila larvae invoke distinct locomotor patterns for either exploratory or nocifensive behaviours. Here we use optogenetics to perform a high-throughput behavioural screen of ventral nerve cord interneurons for their involvement in the performance of nocifensive behaviour. We identified a set of inhibitory premotor neurons (A02e neurons) which were sufficient to delay the onset of nocifensive behaviour. Behavioural characterisation of the A02e neurons revealed activity-dependent modulation of larval posture during escape behaviours, but not basal locomotor behaviours. Further, A02e-related premotor neurons, which recruit heterogeneous motor cohorts, showed differences in the modulation of both exploratory and nocifensive behaviours. Our results suggest that certain premotor neurons are differentially recruited between nocifensive and basal behaviours. Based on the neurons assayed we predict that the somatic lateral and dorsal muscles, but not ventral muscles, are particularly important for the initiation of larval escape behaviours. Therefore, whether a premotor neuron is necessary for the performance of a discrete behaviour, depends on the motor cohorts it innervates.

• Publisher: ProQuest Dissertations & Theses
• Subject: Behavior / Insects / Neurons / Neurosciences
• ISBN: 9798708708656