Oxytocin-dependent consolation behavior in rodents

Abstract

Consolation behavior toward distressed others is common in humans and great apes, yet our ability to explore the biological mechanisms underlying this behavior is limited by its apparent absence in laboratory animals. Here, we provide empirical evidence that a rodent species, the highly social and monogamous prairie vole (Microtus ochrogaster), greatly increases partner-directed grooming toward familiar conspecifics (but not strangers) that have experienced an unobserved stressor, providing social buffering. Prairie voles also match the fear response, anxiety-related behaviors, and corticosterone increase of the stressed cagemate, suggesting an empathy mechanism. Exposure to the stressed cagemate increases activity in the anterior cingulate cortex, and oxytocin receptor antagonist infused into this region abolishes the partner-directed response, showing conserved neural mechanisms between prairie vole and human.

Insular Cortex Mediates Approach and Avoidance Responses to Social Affective Stimuli

“…21, 2017; Insular cortex, oxytocin and social affect 3 OTRs is one of the inclusion criteria for the social brain 4 . Importantly, OT is thought to be an important modulator of empathic cognition in both human 39,40 and animal models 41 .The OTR is a G-protein coupled receptor which activates the Gaq11 signaling cascade 42 , and OTR activation on insular cortex neurons would provide a mechanism for OT to augment insular cortex activity. Indeed, experimenter-administered OT augments behavioral performance in emotion recognition, relieves some social deficits observed in individuals with ASD; and increases insular activity and connectivity to frontal cortex [43][44][45] .…”

“…21, 2017; Insular cortex, oxytocin and social affect 3 OTRs is one of the inclusion criteria for the social brain 4 . Importantly, OT is thought to be an important modulator of empathic cognition in both human 39,40 and animal models 41 .…”

“…There are numerous afferent and efferent tracts connecting the insular cortex to the SDMN, including inputs from the hypothalamus 24 , ventral tegmental area 25 , reuniens nucleus 26 , reciprocal connections with the extended amygdala 27 and efferent connections to periaqueductal gray 28 , bed nucleus of the OTRs is one of the inclusion criteria for the social brain 4 . Importantly, OT is thought to be an important modulator of empathic cognition in both human 39,40 and animal models 41 .…”

“…However, interpreting the underlying cognitive mechanisms is challenging because some paradigms involve repeated conditioning, direct exposure to a conspecific in pain or receiving aversive stimulation [57][58][59][60] , making it difficult to rule out self-serving or socially rewarding motives 41,61 . We developed a rat social affective preference (SAP) test in which social affective behaviors were objectively quantified as a preference to approach or avoid interaction with a conspecific that received a mild stressor.…”

A valence-free definition of sociality as any violation of inter-individual independence

“…The existence of empathy among humans is commonly inferred from actions such as verbal report, consolation behaviour, donating money and helping another in distress. Rats perform similar actions including grooming another who has been shocked, interpreted as consolation, and releasing a trapped rat which the senior author and others have argued constitutes a rodent version of human empathy [6][7]. However, it is plausible that humans express a human version of the rat motivation to help another in distress.…”