Activation of specific mushroom body output neurons inhibits proboscis extension and sucrose consumption

Abstract

The ability to modify behavior based on prior experience is essential to an animal's survival. For example, animals may become attracted to a previously neutral odor or reject a previously appetitive food source based on previous encounters. In Drosophila, the mushroom bodies (MBs) are critical for olfactory associative learning and conditioned taste aversion, but how the output of the MBs affects specific behavioral responses is unresolved. In conditioned taste aversion, Drosophila shows a specific behavioral change upon learning: proboscis extension to sugar is reduced after a sugar stimulus is paired with an aversive stimulus. While studies have identified MB output neurons (MBONs) that drive approach or avoidance behavior, whether the same MBONs impact innate proboscis extension behavior is unknown. Here, we tested the role of MB pathways in altering proboscis extension and identified MBONs that synapse onto multiple MB compartments that upon activation significantly decreased proboscis extension to sugar. Activating several of these lines also decreased sugar consumption, revealing that these MBONs have a general role in modifying feeding behavior beyond proboscis extension. The MBONs that decreased proboscis extension and ingestion are different from those that drive avoidance behavior in another context. These studies provide insight into how activation of MB output neurons decreases proboscis extension to taste compounds.

Azadirachtin-Based Insecticide: Overview, Risk Assessments, and Future Directions

“…In addition to these olfactory and gustatory cues, locomotion represents an integral part of insect behaviors as is essential for food-seeking, mating, and escape response (Zhu et al, 2020). The ability of insects to modify their behavior based on prior experience is essential for their survival (Chia and Scott, 2020). Increasing evidence has highlighted the critical role of early life experience in adult behavior in insects (Caubet et al, 1992;Bezzar-Bendjazia et al, 2016;Ferdenache et al, 2019).…”

Choline Transporter regulates olfactory habituation via a neuronal triad of excitatory, inhibitory and mushroom body neurons

“…There are three types of MB intrinsic neurons, i.e., α/β, α’/β’ and γ neurons, also termed as Kenyon cells (KC). These are distinctly implicated in olfactory learning and memory [ 31 , 32 ]. To understand the role of ChT in MBs, we depleted it in independent domains of MB intrinsic neurons with the help of UAS-GAL4 binary expression system [ 33 ]and investigated if these neurons require ChT function in habituation.…”

Choline Transporter regulates olfactory habituation via a neuronal triad of excitatory, inhibitory and mushroom body neurons

“…There are three types of MB intrinsic neurons i.e, α/β, α’/β’ and ϒ neurons, also termed as Kenyon cells (KC). These are distinctly implicated in olfactory learning, memory (Chia and Scott, 2020; Krashes et al, 2007). To investigate the functional significance of ChT in MB we depleted it in independent domains of MB intrinsic neurons with the help of UAS-GAL4 binary expression system (Brand and Perrimon, 1993) and asked if these neurons require ChT function in habituation learning.…”

“…MB lesion or ablation in Drosophila show elevated locomotor activity (Heisenberg et al, 1985) and diurnal activity (Martin et al, 1998). Recently conditional silencing of MB output neurons (MBON) was reported to show enhanced proboscis extension reflex (Chia and Scott, 2020). Knockdown of dopaminergic receptors (DAMB) in MBON-1 ped>αβ also promotes yeast food-seeking behaviour in fed flies as well as odour seeking behaviour (Tsao et al, 2018).…”