Ethanol induces conditioned social preference in male mice

Deep learning-based scoring method of the three-chamber social behaviour test in a mouse model of alcohol intoxication. A comparative analysis of DeepLabCut, commercial automatic tracking and manual scoring

Background

Alcohol consumption and withdrawal alter social behaviour in humans in a sex-dependent manner. The three-chamber test is a widely used paradigm to assess rodents' social behaviour, including sociability and social novelty. Automatic tracking systems are commonly used to score time spent with conspecifics, despite failing to score direct interaction time with conspecifics rather than time in the nearby zone. Thereby, the automatically scored results are usually inaccurate and need manual corrections.

New method

New advances in artificial intelligence (AI) have been used recently to analyze complex behaviours. DeepLabCat is a pose-estimation toolkit that allows the tracking of animal body parts. Thus, we used DeepLabCut, to introduce a scoring model of the three-chamber test to investigate alcohol withdrawal effects on social behaviour in mice considering sex and withdrawal periods. We have compared the results of two automatic pose estimation methods: automatic tracking (AnyMaze) and DeepLabCut considering the manual scoring method, the current gold standard.

Results

We have found that the automatic tracking method (AnyMaze) has failed to detect the significance of social deficits in female mice during acute withdrawal. However, tracking the animal's nose using DeepLabCut showed a significant social deficit in agreement with manual scoring. Interestingly, this social deficit was shown only in females during acute and recovered by the protracted withdrawal. DLC and manually scored results showed a higher Spearman correlation coefficient and a lower bias in the Bland-Altman analysis.

Conclusion

our approach helps improve the accuracy of scoring the three-chamber test while outperforming commercial automatic tracking systems.

Conditioned preferences: Gated by experience, context, and endocrine systems

Central to the navigation of an ever-changing environment is the ability to form positive associations with places and conspecifics. The functions of location and social conditioned preferences are often studied independently, limiting our understanding of their interplay. Furthermore, a de-emphasis on natural functions of conditioned preferences has led to neurobiological interpretations separated from ecological context. By adopting a naturalistic and ethological perspective, we uncover complexities underlying the expression of conditioned preferences. Development of conditioned preferences is a combination of motivation, reward, associative learning, and context, including for social and spatial environments. Both social- and location-dependent reward-responsive behaviors and their conditioning rely on internal state-gating mechanisms that include neuroendocrine and hormone systems such as opioids, dopamine, testosterone, estradiol, and oxytocin. Such reinforced behavior emerges from mechanisms integrating past experience and current social and environmental conditions. Moreover, social context, environmental stimuli, and internal state gate and modulate motivation and learning via associative reward, shaping the conditioning process. We highlight research incorporating these concepts, focusing on the integration of social neuroendocrine mechanisms and behavioral conditioning. We explore three paradigms: 1) conditioned place preference, 2) conditioned social preference, and 3) social conditioned place preference. We highlight nonclassical species to emphasize the naturalistic applications of these conditioned preferences. To fully appreciate the complex integration of spatial and social information, future research must identify neural networks where endocrine systems exert influence on such behaviors. Such research promises to provide valuable insights into conditioned preferences within a broader naturalistic context.

The effects of alcohol on anxiety-like, depression-like, and social behavior immediately and a day after binge drinking

The aim of the present study was to determine the effects of binge drinking on anxiety-like, depression-like, and social behavior. The participation of the corticotropin-releasing factor (CRF) receptors (CRF1 and CRF2) in these effects was also investigated. Therefore, male C57BL/6 mice were exposed to drinking in the dark, a classical animal model for binge drinking, and treated intracerebroventricularly (icv) with selective CRF1 antagonist antalarmin or selective CRF2 antagonist astressin2B, immediately or 24 h after binge drinking. After 30 min, the animals were investigated in an elevated plus-maze test and a forced swim test for anxiety-like and depression-like signs, respectively. In addition, mice were tested in a three-chamber social interaction arena for sociability and preference for social novelty. Immediately after binge drinking, mice exposed to alcohol expressed anxiolytic and antidepressant effects, which were reduced by astressin2B, but not antalarmin. Moreover, mice exposed to alcohol showed increased sociability and preference for social novelty immediately after binge drinking. In contrast, 24 h after binge drinking mice exposed to alcohol presented anxiety-like and depression-like signs, which were reversed by antalarmin, but not astressin2B. However, mice exposed to alcohol did not show any significant change in social interaction after 24 h. The present study demonstrates that alcohol exerts different effects on anxiety-like, depression-like, and social behavior immediately and a day after binge drinking, and that the anxiolytic and antidepressant effects produced by binge drinking are mediated by CRF2, whereas the anxiety-like and depression-like signs observed the next day are promoted by CRF1.

Does demonstrator relevance affect social preferences and the social transmission of food preferences in female mice (Mus musculus)?

This study examined whether a history of beneficial social learning experiences affects social partner preferences in laboratory mice (Mus musculus) and whether observer mice acquire adaptive model-based social learning strategies through associative learning. We tested whether observers would come to socially prefer demonstrators who provide beneficial information through the social transmission of food preference (STFP), over demonstrators who do not; and whether they would preferentially attend to and learn from such demonstrators. Observers were given repeated exposures to two demonstrators who differed in whether or not they consistently provided beneficial information (which increased observers' ingestion of food via the STFP). After multiple social learning experiences with a "relevant demonstrator" (our CS+) whose demonstrated food was available for consumption (our US) by the observer and a "non-relevant demonstrator" whose demonstrated food was never encountered, neither demonstrator was preferred over the other. Furthermore, observers learned equally well from both relevant and non-relevant demonstrators. The present findings suggest that adaptive model-based social learning strategies are not followed in the STFP, although we recommend further testing of the social preference hypothesis.

Pharmacological (ethanol) and mutation (sam2 KO) induced impairment of novelty preference in zebrafish quantified using a new three-chamber social choice task

Social behavior is a fundamental aspect of our own species, a feature without which our society would not function. There are numerous human brain disorders associated with abnormal social behavior, among them are the autism spectrum disorders whose causal factors include a genetic component. Environmental factors, including drugs of abuse such as alcohol, also contribute to numerous abnormalities related to social behavior. Several such disorders have been modeled using laboratory animals. Perhaps one of the newest among them is the zebrafish. However, the paucity of standardized behavioral assays specifically developed for the zebrafish have hindered progress. Here, we present a newly developed zebrafish behavioral paradigm, the three-chamber social choice task. This task, which was adapted from a murine model, assesses sociality and social novelty preference in zebrafish in three phases: habituation, phase-I to evaluate sociality, and phase-II to quantify social novelty preference. Test fish are placed in the middle chamber, while conspecifics are introduced to the flanking chambers during phase-I and II. Both male and female zebrafish displayed sociality (preference for conspecifics) during phase-I and social novelty preference (preference for unfamiliar conspecifics) during phase-II. We found the paradigm to be able to detect both environmentally (alcohol) as well as genetically (targeted knock out of sam2) induced alterations of behavioral phenotypes. Although ethanol-treated fish displayed similar levels of sociality to those of control (not alcohol exposed) male and female zebrafish, they were found to exhibit significantly impaired social novelty preference, a finding compatible with altered motivational or perhaps mnemonic processes. Moreover, we found that knock out of sam2, previously shown to lead to emotional dysregulation, also disrupted social novelty preference, while leaving sociality relatively intact. We conclude that our novel behavioral paradigm is appropriate for the modeling and quantification of social behavior deficits in zebrafish.

Novel approaches to alcohol rehabilitation: Modification of stress-responsive brain regions through environmental enrichment

Relapse remains the most prominent hurdle to successful rehabilitation from alcoholism. The neural mechanisms underlying relapse are complex, but our understanding of the brain regions involved, the anatomical circuitry and the modulation of specific nuclei in the context of stress and cue-induced relapse have improved significantly in recent years. In particular, stress is now recognised as a significant trigger for relapse, adding to the well-established impact of chronic stress to escalate alcohol consumption. It is therefore unsurprising that the stress-responsive regions of the brain have also been implicated in alcohol relapse, such as the nucleus accumbens, amygdala and the hypothalamus. Environmental enrichment is a robust experimental paradigm which provides a non-pharmacological tool to alter stress response and, separately, alcohol-seeking behaviour and symptoms of withdrawal. In this review, we examine and consolidate the preclinical evidence that alcohol seeking behaviour and stress-induced relapse are modulated by environmental enrichment, and these are primarily mediated by modification of neural activity within the key nodes of the addiction circuitry. Finally, we discuss the limited clinical evidence that stress-reducing approaches such as mindfulness could potentially serve as adjunctive therapy in the treatment of alcoholism. This article is part of the Special Issue entitled "Neurobiology of Environmental Enrichment".

Social housing conditions and oxytocin and vasopressin receptors contribute to ethanol conditioned social preference in female mice

Social behavior modulates response to alcohol. Because oxytocin (OXT) and vasopressin (AVP) contribute to rewarding social behavior, the present study utilized a genetic strategy to determine whether OXT and AVP receptors (OXTR, AVPR1a) are essential for female mice to demonstrate a conditioned social preference for ethanol. The study compared wild-type (WT) and knock-out (KO) females lacking either Oxtr or Avpr1a in a conditioned social preference (CSP) test. KO females and WT females from Het-Het crosses were pair-housed: KO and WT(ko). WT females from Het-WT crosses were pair-housed: WT(wt). Test mice received 2g/kg ethanol or saline ip, and were paired four times each with one stimulus female (CS-) after saline, and with another female (CS+) following ethanol. After pairing, the time spent with CS+ and CS- females was measured. WT(wt) females showed conditioned preference for the CS+ female paired with ethanol, demonstrated by greater interaction time (p<0.05). In both KO lines, ethanol significantly reduced interaction with the CS+ female (p<0.05), and there was no change in interaction for WT(ko) females. Response to odors by habituation-dishabituation was unaffected in both KO lines, and the response to a hypnotic dose of ethanol also was the same as in WT mice. However, anxiety, measured as time on the open arms of the elevated plus maze, was reduced in KO(Oxtr) females compared with WT(wt). The results suggest that Oxtr and Avpr1a are required for conditioned effects of an ethanol-associated social stimulus. The lack of CSP in WT(ko) females suggests that the quality of social interactions during postnatal and postweaning life may modulate development and expression of normal social responses.