Science, Medicine, and the Anesthesiologist

Prosocial behaviors are pivotal for promoting survival and social cohesion among animals. Injury triggers instinctive responses alleviating pain and reducing infection risks through behaviors like licking. In social contexts, animals exhibit caring behaviors to counterparts, such as wound licking, to tend to the injuries. However, the characterization of such behaviors and the underlying neural circuitry remains elusive. Employing sophisticated approaches encompassing behavioral analysis, micro-endoscopic calcium imaging, and opto- and chemogenetic analyses in mice, the authors characterized allogrooming and allolicking behaviors from naive cagemates (observers) toward animals suffering from acute injury (demonstrators). To explore the neural circuitry governing prosocial behaviors, the authors analyzed neuronal activity within the anterior cingulate cortex (ACC), implicated in perceiving and socially transmitting others’ pain. Findings revealed distinct subsets of ACC neurons displaying activity specific to others’ pain states, separate from responses to others’ stress. ACC neurons selectively exhibited increased activation to either self-pain or observation of others’ pain, but not both. Chemogenetic manipulation of ACC neuronal activity altered prosocial behaviors in observer animals. Ultimately, utilizing subsets of 297 neurons during allolicking and 354 neurons during allogrooming behaviors, the authors demonstrate that the ACC encoded specific pattern of neuronal activation with minimal overlap (60 neurons) between the two behaviors.

Take home message: This study highlights the neural mechanisms orchestrating prosocial responses to injury, shedding light on the nuanced functioning of the ACC in these behaviors. It may ultimately aid in developing treatments for impaired prosocial behaviors in a variety of brain disorders.