Biology subjects

Parkitna, J. R.

Publications and source records attributed to Parkitna, J. R..

3 recordsLinked to original sources

bioRxiv2025

Modeling social influence as a reinforcer reveals varying individual learning strategies and the group's structure

In a social context, knowledge can be gained through observation and imitation, but in a numerous group, social influence can also be contradictory and confusing. The mechanisms of social learning in groups have not been fully characterized, partly due to the lack of adequate mathematical description. Using the known reinforcing property of social influence we introduce a reinforcement learning model which can account for social effects at the group and individual level. We use it to reveal pairwise influence relations and the overall learning strategies in a reversal learning task applied to a cohort of mice housed in an Intellicage. Animals make an efficient use of social influence when the goal of the group agrees with their own, but switch to an individual learning scheme when these goals are misaligned. They also exhibit varied decision rules depending on their own motivational state, and a selectivity in assimilating social information depending on the state of their conspecifics.

animal behavior and cognition↗

bioRxiv2023

Dopamine receptor-expressing neurons are differently distributed throughout layers of the motor cortex to control dexterity

The motor cortex comprises the primary descending circuits for flexible control of voluntary movements and is critically involved in motor skill learning. Motor skill learning is impaired in patients with Parkinsons disease, but the precise mechanisms of motor control and skill learning are still not well understood. Here we have used transgenic mice, electrophysiology, in situ hybridization and neural tract-tracing methods to target genetically defined cell types expressing D1 and D2 dopamine receptors (D1+ and D2+, respectively) in the motor cortex. We observed that D1+ and D2+ neurons are organized in highly segregated, non-overlapping populations. Moreover, based on ex vivo patch-clamp recordings, we showed that D1+ and D2+ cells have distinct morphological and electrophysiological properties. Finally, we observed that chemogenetic inhibition of D2+, but not D1+ neurons, disrupts skilled forelimb reaching in adult mice. Overall, these results demonstrate that dopamine receptor-expressing cells in the motor cortex are highly segregated and play a specialized role in manual dexterity.

neuroscience↗

bioRxiv2023

Mu-opioid receptor-dependent changes in social reward across adolescence in mice

RationaleSocial behaviors undergo dramatic changes during adolescence, enabling the development of adult social abilities. These changes are intricately linked to the development of the brain reward system and the activity of endogenous opioid signaling. However, the involvement of the opioid system in the development of social behaviors still raises more questions than answers. ObjectivesHere, we investigated the role of the endogenous opioid system in the rewarding effects of social contact in early and late adolescent male mice. MethodsSocial reward was assessed using the social conditioned place preference task in early adolescent (~34 days old) and late adolescent (~41 days old) male mice that received a single dose of the selective opioid receptor antagonists cyprodime (1 mg/kg, i.p.), naltrindole (1 mg/kg, i.p.) or norbinaltorphimine (10 mg/kg, i.p.) before the preference posttest. ResultsThe administration of cyprodime or naltrindole before the posttest significantly increased the preference for the social-conditioned context in early but not late adolescent mice. In contrast, pretreatment with norbinaltorphimine had no effect on context preference. ConclusionsOur findings support a modified version of the state-dependent mu-opioid receptor model of social behavior, where the effects of opioid ligands are not reversed during development but rather weaken or disappear with age. Furthermore, the results indicate that interactions with siblings in early adolescent mice are motivated by negative reinforcement, whereas those in late adolescence are motivated by positive reinforcement.

neuroscience↗