SAN DIEGO, CA — Studies of how the brain processes social behavior are unraveling the complexities of how positive and negative interpersonal interactions may have long-term effects on neural function and memory. The findings were presented at Neuroscience 2022, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.
It has been historically challenging to study social behavior in the brain. New tools, including powerful imaging, machine learning and computational advances are improving the ability to measure behavioral and neurological changes with greater nuance and specificity. As societal factors — such as advancing technology and the COVID-19 pandemic — are changing when and how people interact and communicate, the need to understand social behavior and the brain is more important than ever.
Today’s new findings show that:
- A novel reward circuit in the brain differentiates between positive and negative social experiences, which could help guide future social behavior based on previous interactions. (Pedro Espinosa, University of Geneva)
- A small group of neurons in the hypothalamus signal social interaction or isolation, providing greater insight into the neuronal basis of social need. (Ding Liu, Harvard University)
- In mice, a population of stress/threat-responsive neurons encode past social trauma and over-activate in subsequent, non-threatening situations, supporting the idea that social trauma impairs brain reward function. (Long Li, Icahn School of Medicine at Mount Sinai)
- Rats were less likely to help trapped cage mates when the trapped animals appeared less distressed (as a consequence of being treated with anxiety medication), suggesting that an experience of shared suffering may promote altruistic behavior. (Hassan Lopez, Skidmore College)
"The importance of social structures and connections are often overlooked, but they are vital to our physical and mental health," said session moderator Moriel Zelikowsky, an assistant professor in the Department of Neurobiology and Anatomy at the University of Utah School of Medicine. "Moving forward, a stronger understanding of the importance of social connections, the debilitating effects of social isolation, and how interpersonal relationships affect the brain will be important for understanding not just basic human nature, but also disease states such as depression and anxiety."
This research was supported by national funding agencies including the National Institutes of Health and private funding organizations. Find out more about social isolation, stress, and cognitive function on BrainFacts.org.
Press Conference Summary
- Social behaviors have wide-ranging physical and mental effects on individuals, but the neural underpinnings can be challenging to study.
- Through a variety of creative methods, scientists are identifying specific neurons and neural circuits that respond to positive and/or negative social interactions, offering insights into the nature of social behavior, motivation, and even empathy.
The Circuit Basis of Social Valence
Pedro Espinosa, email@example.com, Abstract 650.01
- The brain’s reward pathways help us evaluate the quality of social interaction, but it is not well known how specific neuronal circuits may encode positive or negative associations that would guide an appropriate behavioral response.
- In rodents, the pattern of activity of a newly identified circuit between the insular cortext and the nucleus accumbens and the cortex differs between good and bad social experiences.
- Low frequency activity of this circuit reflects rewarding experiences and high frequency activity encodes negative experiences, potentially allowing these cells to guide future social behavior based on previous interactions.
Neural Control of the Homeostatic Need for Social Interactions
Ding Liu, firstname.lastname@example.org, Abstract 236.26
- In animals, social need — seeking social interaction for survival and mutual benefit — seems to be an evolutionarily supported instinct, but the neural basis of this need is not clear.
- In mice, scientists identified novel populations of hypothalamic neurons that are activated by either social interaction or isolation.
- These cells offer a starting point to investigate neural circuits that encode social need and the mental problems associated with social isolation.
Traumatic Social Experience Engages Lateral Septum Neurotensin Circuitry to Occlude Social Reward
Long Li, email@example.com, Abstract 146.17
- Traumatic social experiences can lead to social avoidance and psychiatric disorders, possibly by impairing reward responses in the brain.
- In mice subjected to chronic social defeat stress, social trauma was encoded by a population of stress/threat-responsive neurons in the lateral septum, a reward-related region of the brain.
- Hyperactivation of these neurons during later, non-threatening interactions led the animals to avoid previously rewarding social interactions.
Pharmacological Attenuation of Distress Reduces Altruistic Behavior in the Trapped Rat Paradigm
Hassan Lopez, firstname.lastname@example.org, Abstract 236.14
- Altruism and "helping behavior" have been widely observed among social animals, but the motivation for such behavior is unclear. One theory is that “emotional contagion,” or the capacity to experience another’s suffering, may lead helpers to assist a victim to reduce their own distress.
- "Free rats" were given the opportunity to assist a trapped cage mate by opening an apparatus locked from the outside.
- Half of the trapped animals were given the anti-anxiety drug midazolam to reduce their expressions of distress. Free rats were less likely to assist the less-distressed animals by opening the apparatus.