Reward signaling in a recurrent circuit of dopaminergic neurons and peptidergic Kenyon cells

Abstract

Dopaminergic neurons in the brain of the Drosophila larva play a key role in mediating reward information to the mushroom bodies during appetitive olfactory learning and memory. Using optogenetic activation of Kenyon cells we provide evidence that recurrent signaling exists between Kenyon cells and dopaminergic neurons of the primary protocerebral anterior (pPAM) cluster. Optogenetic activation of Kenyon cells paired with odor stimulation is sufficient to induce appetitive memory. Simultaneous impairment of the dopaminergic pPAM neurons abolishes appetitive memory expression. Thus, we argue that dopaminergic pPAM neurons mediate reward information to the Kenyon cells, and in turn receive feedback from Kenyon cells. We further show that this feedback signaling is dependent on short neuropeptide F, but not on acetylcholine known to be important for odor-shock memories in adult flies. Our data suggest that recurrent signaling routes within the larval mushroom body circuitry may represent a mechanism subserving memory stabilization.

The Neural Basis for a Persistent Internal State inDrosophilaFemales

“…For example, recurrent networks in rats (Chen et al, 2017), fish (Aksay et al, 2007), and flies (Cognigni et al, 2018;Jung et al, 2020;Kim et al, 2017;Zhang et al, 2019;Zhao et al, 2018) contribute to persistent activity underlying short-term memory, although the precise mechanism, whether relying on intrinsic properties of individual neurons or on the connectivity within neural circuits, may vary across systems (Barak and Tsodyks, 2007;Major and Tank, 2004;Zylberberg and Strowbridge, 2017). While persistent activity was shown to outlast stimulation for minutes in slices or in isolated brains (e.g., (Egorov et al, 2002;Lyutova et al, 2019)), short-term or working memory related persistent activity in vivo typically lasts for seconds (Aksay et al, 2007), even when the delay period between stimulus presentation and behavior is variable (Park et al, 2019). Internal states underlying social behaviors, as we have shown here, persist on very long timescales of many minutes.…”

Assessing the Cognitive Status of Drosophila by the Value-Based Feeding Decision

“…However, it is still possible Shi ts proteins may not completely silence the MB activity. Finally, we examined the VBFD in flies with altered dopaminergic rewarding system and feeding-promoting NPF signals (12,31,32). Surprisingly, the making of proper with nutritional value to resolve the energy need.…”

Identification ofFoxPcircuits involved in locomotion and object fixation inDrosophila

“…The insect mushroom-bodies (MBs) are not only known as a center for olfactory learning and memory (Dolan et al, 2018;Felsenberg et al, 2018;König et al, 2019;Lyutova et al, 2019;Thum and Gerber, 2019;Turrel et al, 2018;e.g., Warth Pérez Arias et al, 2020;Widmer et al, 2018), they are also involved in the temporal and spatial control of locomotor activity (Besson and Martin, 2005;Helfrich-Förster et al, 2002;Lark et al, 2017;Lebreton and Martin, 2009;Mabuchi et al, 2016;Manjila et al, 2019;e.g., Martin et al, 1998;Serway et al, 2009;Sun et al, 2018;Xiong et al, 2010). In addition, (Castells-Nobau et al, 2019) (Fig.…”