Biology subjects

Hanesse, B.

Publications and source records attributed to Hanesse, B..

2 recordsLinked to original sources

bioRxiv2022

Dopamine builds and reveals reward-associated latent behavioral attractors

Phasic variations in dopamine levels are interpreted as a teaching signal reinforcing rewarded behaviors. However, behavior also depends on the online, neuromodulatory effect of phasic dopamine signaling. Here, we unravel a new neurodynamical principle that reconciles these roles. In a biophysical recurrent network-based decision architecture, we showed that dopamine-mediated synaptic plasticity stabilized neural assemblies representing rewarded locations as latent, local attractors. Dopamine-modulated synaptic excitability activated these attractors online, and they became accessible as internal goals, even from remote animal positions. We experimentally validated these predictions in mice, using optogenetics, by demonstrating that online dopamine signaling specifically attracts animals toward rewarded locations, without off-target motor effects. We therefore propose that online dopamine signaling reveals potential goals by widening and deepening the basin of dopamine-built attractors representing rewards.

neuroscience↗

bioRxiv2020

Distinct dopamine circuits transmit the reinforcing and anxiogenic effects of nicotine

Nicotine, the addictive component of tobacco, stimulates dopamine (DA) neurons of the ventral tegmental area (VTA) to establish and maintain reinforcement. Nicotine also induces negative emotional states such as anxiety, yet through an unknown circuitry. Here we show that nicotine at reinforcing doses drives opposite functional responses on two distinct populations of VTA DA neurons with anatomically segregated projections: it activates those that project to the nucleus accumbens (NAc) while it inhibits those that project to the amygdala nuclei (Amg). We further show that nicotine, by acting on {beta}2 subunit-containing nicotinic acetylcholine receptors of the VTA, mediates both reinforcement and anxiety. Finally, using optogenetic experiments we dissociate the roles of the VTA-NAc excitation and VTA-Amg inhibition in reinforcement and anxiety-like behavior, respectively. We thus propose that the positive and negative behavioral outcomes of nicotine consumption involve distinct subpopulations of VTA DA neurons with opposite responses to nicotine.

neuroscience↗