Biology subjects

Tarot, P.

Publications and source records attributed to Tarot, P..

3 recordsLinked to original sources

bioRxiv2021

Selection of active defensive behaviors relies on extended amygdala dopamine D2 receptors

The ability to efficiently switch from one defensive strategy to another maximizes an animals chance of survival. Here, we demonstrate that the selection of active defensive behaviors requires the coordinated activation of dopamine D2 receptor (D2R) signaling within the central extended amygdala (EA) comprising the nucleus accumbens, the oval bed nucleus stria terminals and the central amygdala. We find that discriminative learning between predictive and non-predictive threat auditory stimuli is unaltered in mice carrying a temporally-controlled deletion of D2R within output neurons of the EA. In contrast, intact EA D2R signaling is required for active avoidance learning and innate flight responses triggered by a visual threat stimulus (looming). Consequently, conditional D2R knockout mice biased defensive responses toward passive defensive strategies. Altogether, these findings identify EA D2R signaling as an important mechanism by which DA regulates the switch from passive to active defensive behaviors, regardless whether of learned or innate threat.

neuroscience↗

bioRxiv2019

Cerebellar dopamine D2 receptors regulate preference for social novelty

The cerebellum, a primary center involved in the control of sensorimotor tasks, also contributes to higher cognitive functions including reward, emotion and social interaction. The regulation of these behaviors has been largely ascribed to the monoaminergic system in limbic regions. However, the contribution of cerebellar dopamine signaling in the modulation of these functions remains largely unknown due to the lack of precise characterization of cerebellar dopaminoceptive neurons. By combining cell type-specific transcriptomic and histological analyses, 3D imaging and electrophysiology we demonstrate that cerebellar dopamine D2 receptors (D2R) in mice are preferentially expressed in Purkinje cells (PCs). While activation of D2R regulate synaptic efficacy onto PCs, their deletion or overexpression in PCs bidirectionally controls preference for social novelty without affecting motor functions. Altogether, these findings demonstrate novel D2Rs roles in PC function and causally link cerebellar D2R levels of expression to social behaviors.

neuroscience↗

bioRxiv2019

Contrasting patterns of ERK activation in the tail of the striatum in response to aversive and rewarding signals

The caudal part of the striatum, also named the tail of the striatum (TS), defines a fourth striatal domain. Determining whether rewarding, aversive and salient stimuli regulate the activity of striatal spiny projections neurons (SPNs) of the TS is therefore of a paramount importance to understand its functions, which remain largely elusive. Taking advantage of genetically encoded biosensors (AKAR3) to record PKA signals and by analyzing the distribution of D1R-and D2R/A2aR-SPNs in the TS, we characterized three evolutionary highly conserved subterritories: a D2R/A2aR-lacking area, a D1R/D2-SPNs-enriched and an D1R/D2R-intermingled area. The analysis of ERK phosphorylation in these TS subterritories in response to distinct appetitive, aversive and pharmacological stimuli revealed that SPNs of the TS are not recruited by stimuli triggering innate or learned avoidance responses, fasting, satiety or palatable signals. In contrast, D1R-SPNs of the intermingled and D2R/A2AR-lacking areas are strongly activated by both direct stimulation of D1R and psychostimulant drugs (d-amphetamine, cocaine, MDMA or methylphenidate), but not by hallucinogens. Finally, a similar pattern of ERK activation was observed by blocking selectively dopamine reuptake. Together, our results reveal that the caudal TS might participate in the processing of specific reward signals.

neuroscience↗