Investigating the Role of the VTA and PVN in Social Motivation

Abstract

Social motivation is often disrupted in neuropsychiatric conditions, and two brain regions, the ventral tegmental area (VTA) and the paraventricular nucleus (PVN), are thought to play key roles through their dopamine- and oxytocin-related pathways. However, little is known about how activating these regions directly affects social behavior, especially when effort is required. This study used optogenetics to selectively stimulate neurons in either the VTA or the PVN of adult mice and examined how this influenced a range of social and effort-based behaviors. Across tasks, stimulation of the VTA produced clear sex-dependent effects. Male mice showed increases in exploration, social approach, novelty preference, and performance on effortful tasks like climbing and pushing a weighted door. In contrast, females often showed reduced motivation under the same stimulation, suggesting that dopamine-related circuits may respond differently across sexes. Stimulation of the PVN led to more subtle effects that depended on the specific context. PVN activation influenced social behavior in certain situations, such as familiarity preference or low-effort social exploration, but did not consistently increase motivated behavior when effort demands were high.