Biology subjects

BAUNEZ, C.

Publications and source records attributed to BAUNEZ, C..

9 recordsLinked to original sources

bioRxiv2026

Subthalamic Nucleus Optogenetic Inhibition Bidirectionally Regulates Social Motivation According to Familiarity and Social Hierarchy

BackgroundSocial behavior is a core component of mental health, and its disruption characterizes many neuropsychiatric disorders such as autism. Social operant paradigms enable the quantification of volitional aspects of social motivation and interactions. While sex differences have been shown to influence social motivation, factors such as familiarity and social hierarchy are also likely to play a critical role that remain insufficiently explored. In addition, the subthalamic nucleus (STN), traditionally studied in motor circuits, has emerged as an important regulator of reward and motivational processes and may contribute to social behavior processes. MethodsIn this study, we examined the influence of peer familiarity (cagemate vs. stranger) and social hierarchy (dominant vs. subordinate) 1) on operant volitional social interaction using a fixed ratio 1 (FR1) and 2) on social motivation using a progressive ratio (PR) schedule of reinforcement in non-isolated rats. To assess the causal contribution of the STN, we used optogenetic photo-inhibition during both tasks in male rats. ResultsMale rats displayed a reduction of social interest and motivation toward familiar peers, mainly driven by the social hierarchy, while female did not. STN photo-inhibition in males abolished the familiarity-driven reduction under FR1 but decreased motivation independently of familiarity or hierarchy in PR. ConclusionsThese findings highlight sex, familiarity, and hierarchy as key modulators of volitional social behavior and demonstrate a direct role of the STN in regulating social motivation. Together, they provide mechanistic insights into processes that may be disrupted in neuropsychiatric disorders characterized by social dysfunction.

neuroscience↗

bioRxiv2026

THE SUBTHALAMIC NUCLEUS IS INVOLVED IN SOCIAL MEMORY IN MALE RATS

Human social behavior depends on complex socio-cognitive abilities, many of which are disrupted in neuropsychiatric disorders. We previously found that subthalamic nucleus (STN) lesions abolish familiarity-based modulation of social reward in rats, implicating the STN in social recognition. Here, we used pharmacological lesions, electrical deep brain stimulation (DBS), and optogenetic manipulations to dissect the STNs role in social memory. STN lesions selectively impaired social discrimination memory without affecting social novelty discrimination or non-social memory. High-frequency optogenetic stimulation disrupted social discrimination memory only when applied during encoding, whereas STN optogenetic inhibition, and electrical DBS impaired social memory when applied during either encoding or retrieval. Notably, transient optogenetic inhibition abolished recognition of a cage-mate after short isolation, yet this ability was preserved after permanent lesions, suggesting compensatory adaptations. These results identify the STN as a key node for social memory and highlight the importance of considering its role in social cognition when implementing STN-targeted therapies.

neuroscience↗

bioRxiv2025

Cocaine withdrawal enhances subthalamic reward sensitivity

High-frequency stimulation of the subthalamic nucleus (STN) has shown therapeutic potential in preclinical models of addiction. However, its rewarding properties remain unclear. Here, we show that cocaine withdrawal enhances STN intracranial self-stimulation, revealing a reward-based mechanism that may contribute to the beneficial effects of STN deep brain stimulation in addiction and related neuropsychiatric disorders.

neuroscience↗

bioRxiv2025

Cocaine extended access gates compulsive-like seeking in rats

When does compulsive-like drug seeking emerge? Despite decades of research, and critical advances in our understanding of brain processes leading to addiction, this question remains widely unanswered. So far, behavioral models assessing compulsive-like cocaine seeking following an extended access to cocaine failed to capture the development of its compulsive seeking. In fact, compulsive-like animals immediately displayed pathological seeking when facing its negative consequences of drug seeking, usually materialized by an unescapable mild electric shock on the paws. Here, we designed a new task, Punished Seeking during Extended access (PSE), by inserting punished seeking trials within the sessions of extended access to cocaine. We show that compulsive-like cocaine seeking progressively emerges after several PSE sessions, once cocaine intake has been escalated. We thus provide the addiction community a pertinent model to explore brain mechanisms sustaining the emergence of compulsive-like cocaine seeking.

neuroscience↗

bioRxiv2023

SUBTHALAMIC HIGH-FREQUENCY DEEP BRAIN STIMULATION REDUCES ADDICTION-LIKE ALCOHOL USE AND SUPPRESSES THE OVERCONSUMPTION INDUCED BY THE PEER S PRESENCE

RationalThe immediate social context significantly influences alcohol consumption in humans. Recent studies have revealed that peer presence could modulate drugs use in rats. The most efficient condition to reduce cocaine intake is the presence of a stranger peer, naive to drugs. Deep brain stimulation (DBS) of the Subthalamic Nucleus (STN), which was shown to have beneficial effects on addiction to cocaine or alcohol, also modulate the protective influence of peers presence on cocaine use. ObjectivesThis study aimed to: 1) explore how the presence of an alcohol-naive stranger peer affects recreational and escalated alcohol intake, and 2) assess the involvement of STN on alcohol use and in the modulation induced by the presence of an alcohol-naive stranger peer. MethodsRats with STN DBS and control animals self-administered 10% (v/v) ethanol in presence, or absence, of an alcohol-naive stranger peer, before and after escalation of ethanol intake (observed after intermittent alcohol (20% (v/v) ethanol) access). ResultsNeither STN DBS nor the presence of an alcohol-naive stranger peer modulated significantly recreational alcohol intake. After the escalation procedure, STN DBS gradually reduced ethanol consumption. The presence of an alcohol-naive stranger peer increased consumption only in low drinkers, which effect was suppressed by STN DBS. ConclusionsThese results highlight the influence of a peers presence on escalated alcohol intake, and confirm the role of STN in addiction-like alcohol intake and in the social influence on drug consumption.

neuroscience↗

bioRxiv2023

THE SUBTHALAMIC NUCLEUS IS INVOLVED IN SOCIAL RECOGNITION MEMORY IN RATS

Human social behavior is a complex construct requiring a wide range of cognitive abilities and is critically impaired in numerous neuropsychiatric diseases. Living in complex social groups, rodents offer suitable models to elucidate neural processing of social cognition. Recently, a potential involvement of the subthalamic nucleus (STN) in rats social behavior has been pointed out. For example, we showed that STN lesions abolish the modulatory effect of the familiarity on the rewarding value of social stimuli, questioning the involvement of STN in peer recognition. In this study, we thus assess the effects of STN lesions and optogenetic manipulations on peer and object recognition. STN optogenetic inhibition, like lesions, impair social recognition memory, while STN optogenetic high-frequency (HF) stimulation leads to a specific alteration of social encoding memory. None of these manipulations seem to interfere with social investigation, objects recognition memory, nor social novelty preference. Finally, STN optogenetic inhibition, but neither HF-stimulation, nor lesions, leads to an alteration of the cage-mate recognition memory. Overall, these results show that physiological activity of STN is necessary for rats to show a proper social recognition memory performance and question the possible detrimental effects of STN deep brain stimulation on these processes in human patients.

neuroscience↗

bioRxiv2021

Peer presence and familiarity as key factors to reduce cocaine intake: an effect mediated by the Subthalamic Nucleus

Stimulant use, including cocaine, often occurs in a social context whose influence is important to understand to decrease intake and reduce associated harms. Given the regulatory role of the subthalamic nucleus (STN) on cocaine intake and emotions, we investigate its role on such influence of social context on cocaine intake. We explored the influence of peer presence and familiarity on the frequency of self-administered cocaine and its neurobiological basis. We first compared cocaine intake in various conditions (alone or with peers with different characteristics: observing or self-administering, familiar or not, cocaine-naive or not, dominant or subordinate) in rats (n=90). The risk of drug consumption was reduced when a peer was present, observing or self-administering as well, and further diminished when the peer was unfamiliar (vs familiar). The presence of a cocaine-naive peer further decreased cocaine consumption. The presence of a non-familiar and drug-naive peer represents thus key conditions to diminish cocaine intake. We tested the effects of STN lesions in these various conditions and also conducted social experiments to validate the role of STN in social cognition. The STN lesion by itself reduced cocaine intake to the level reached in presence of a stranger naive peer and affected social cognition, positioning the STN as one neurobiological substrate of social influence on drug intake. Finally, with a translational research approach, we compared the drug intake in these conditions in human drug users (n=77). This human study confirmed the beneficial effect of social presence, especially of strangers. Our results indirectly support the use of social interventions and harm reduction strategies, in particular supervised consumption rooms for stimulant users.

neuroscience↗

bioRxiv2021

Evidence for a vocal signature in the rat and its reinforcing effects

While the term "language" is used for human and non-human primates, "vocal communication" is rather used for rodents or other species. The main difference is that there is, to date, no evidence for a vocal signature in the well-known 50- and 22-kHz ultrasonic vocalizations (USV) emitted by rats. Here, we show that rats can recognize the identity of the USV emitter since they self-administer preferentially playback of 50-kHz USV emitted by a stranger rat over those emitted by their cage-mate. In a second experiment, we show that the familiarity with the USV emitter also modulate the effect of USV playback during cocaine self-administration, since only stranger, but not familiar, 50-kHz USV decrease drug intake. Finally, to study the neurobiological substrate of those processes, we have tested the effects of the subthalamic nucleus (STN) lesion on these various conditions. STN-lesioned rats did not lever press much for any USV playback, whatever their emotional valence, nor did they seem able to differentiate familiar from stranger peer. Advocating for the existence of a vocal signature in rats, these results highlight the importance of ultrasonic communication in socio-affective influence of behavior, such as the influence of proximal social factors on drug consumption and confirm the role of the subthalamic nucleus on this influence.

animal behavior and cognition↗

bioRxiv2018

Subthalamic nucleus mediates the modulation on cocaine self-administration induced by ultrasonic vocalizations playback in rats

Drug intake is known to be under the influence of social context. We have recently shown that presence of a peer influences drug intake in both rats and humans. Whether or not social acoustic communications between the peers play a role during cocaine or sucrose self-administration (SA) was investigated here, using playback of ultrasonic vocalizations (USV) at 50- and 22-kHz, conveying respectively positive and negative internal affective states in adult rats. To assess the neurobiological substrate of a potential USV influence on drug and food intake, we tested the effects of subthalamic nucleus (STN) lesions, given its role in emotional and motivational processes. In sham-control rats, playback of USV associated with positive affective states induced long-term decreased cocaine consumption, while USV associated with negative affective states induced short-term increase. Interestingly, no effect of USV playback was observed on sucrose intake, whatever the frequency. STN lesions abolished the influence of USV on cocaine intake, highlighting the influence of STN in emotional processes induced by USV emitted by a peer. These results show how acoustic social communication is important to regulate drug intake in rats and how STN modulation could interfere with addiction processes.

neuroscience↗