Structural and functional sex differences in the ventral pallidal vasopressin system are associated with the sex-specific regulation of juvenile social play behavior in rats

The ventral pallidum (VP) has been implicated in the regulation of rewarding adult social behaviors, such as pair-bonding and sociosexual motivation. However, the role of the VP in regulating rewarding juvenile social behaviors, such as social play, is unknown. Social play is predominantly displayed by juveniles of many mammalian species and engagement in social play helps develop social competence. In this study, we determined whether the VP is involved in regulating social play in juvenile rats by temporarily inactivating the VP via bilateral infusions of muscimol, the GABAA receptor agonist. Muscimol treatment decreased social play duration in males and females compared to the same-sex control groups. We then focused on the vasopressin (AVP) system in the VP as one potential modulator of social play. We examined the organization of the AVP system in the VP in juvenile rats and found robust sex differences, with denser AVP-immunoreacive fibers and denser vasopressin 1a receptor (V1aR) binding in males compared to females, but a greater number of V1aR-expressing cells in females compared to males. Next, we determined whether exposure to social play changed the activation of V1aR-expressing VP cells in male and female juvenile rats. We found that exposure to social play enhanced the number of V1aR-expressing VP cells co-expressing fos, a marker of neuronal activation, in males only. Finally, we determined the causal involvement of AVP signaling in the VP in social play behavior by infusion of a specific V1aR antagonist into the VP prior to social play exposure. We found that V1aR blockade in the VP increased social play duration in juvenile male rats but decreased social play duration in juvenile female rats compared to same-sex control groups. These findings reveal structural and functional sex differences in the AVP system in the VP that are associated with the sex-specific regulation of juvenile social play behavior.

A Chromosome-Level Genome Assembly of the Dark Sleeper Odontobutis potamophila

The dark sleeper, Odontobutis potamophila, is a commercially valuable fish that widely distributed in China and Southeast Asia countries. The phenomenon of sexual dimorphism in growth is conspicuous, which the males grow substantially larger and faster than the females. However, the high-quality genome resources for gaining insight into sex-determining mechanisms to develop sex-control breeding are still lacking. Here, a chromosomal-level genome assembly of O. potamophila was generated from a combination of Illumina reads, 10× Genomics sequencing, and Hi-C chromatin interaction sequencing. The assembled genome was 1,134.62 Mb with a contig N50 of 22.25 Mb and a scaffold N50 of 24.85 Mb, representing 94.4% completeness (Benchmarking Universal Single-Copy Orthologs). Using Hi-C data, 96.49% of the total contig bases were anchored to the 22 chromosomes, with a contig N50 of 22.25 Mb and a scaffold N50 of 47.68 Mb. Approximately 54.18% of the genome were identified as repetitive elements, and 23,923 protein-coding genes were annotated in the genome. The assembled genome can be used as a valuable resource for molecular breeding and functional studies of O. potamophila in the future.

Environment and sex control lifespan and telomere length in wild-derived African killifish

ABSTRACTTelomere length is correlated positively with longevity at the individual level, but negatively when compared across species. Here, we tested the association between lifespan and telomere length in African annual killifish. We analyzed telomere length in 18 Nothobranchius strains derived from diverse habitats and measured the laboratory lifespan of 14 strains of N. furzeri and N. kadleci. We found that males had shorter telomeres than females. The longest telomeres were recorded in strains derived from dry region where male lifespans were shortest. At the individual level, we detected a weak negative association between rapid juvenile growth and shorter telomeres in early adulthood. Overall, average telomere length was a good descriptor of telomere length distribution. However, within-individual telomere length spread was not related to any pattern. This substantial variation in telomere length between strains from different environments provides killifish as powerful tool to understand the evolutionarily adaptive value of telomere length.

The Effects of Age, Gender, and Control Device in a Virtual-Reality Driving Simulation

The application of Virtual Reality in a driving simulation is not novel, yet little is known about the use of this technology by senior populations. The effects of age, sex, control device (joystick or handlebar), and task type on wayfinding proficiency using a virtual reality (VR) driving simulation were explored. The driving experimental model involved 96 randomly recruited participants, including 48 young people and 48 seniors (split evenly by gender in each group). The experimental results and statistical analyses indicate that in a VR driving scenario task type significantly affected VR driving performance. Navigational scores were significantly higher for the straight (easy) task than for the curved (difficult) task. The aging effect was the main reason for significant and interacting effects of sex and control device. It was found that interactions between age and sex difference indicated that the young group exhibited better wayfinding performance than the senior group, and in the young group males had better performance than females. Similarly, interactions between age and control device indicated that the handlebar control device type resulted in better performance than the joystick device in the young group, but no difference was found in the senior group due to age or learning effects. Findings provide an understanding of the evaluation of the interface designs of navigational support systems, taking into consideration any effects of age, sex, control device, and task type within three-dimensional VR games and driving systems. With a VR driving simulator, seniors can test drive inaccessible products, such as electric bicycles or cars, using a computer at home.