Rodent empathy and affective neuroscience

Abstract

In the past few years, several experimental studies have suggested that empathy occurs in the social lives of rodents. This indicates that rodent behavioral models can be developed in an attempt to elucidate the mechanistic substrates of empathy at levels that have heretofore been unavailable. For example, the finding that mice from certain inbred strains express behavioral and physiological responses to conspecific distress, while others do not, underscores that the genetic underpinnings of empathy are specifiable and that in the future they could be harnessed to develop new therapies for human psychosocial impairments. However, the advent of rodent models of empathy is met at the outset with a number of theoretical and semantic problems that are similar to those previously confronted by studies of empathy in humans. The distinct underlying components of empathy must be differentiated from one another and from lay usage of the term. The primary goal of this paper is to review a set of seminal studies that are directly relevant to developing a concept of empathy in rodents. We first consider some of the psychological phenomena that have been associated with empathy, and within this context, we consider the component processes, or endophenotypes of rodent empathy. We then review a series of recent experimental studies that demonstrate the capability of rodents to detect and respond to the affective state of their social partners. We focus primarily on experiments that examine how rodents share affective experiences of fear, but we also highlight how similar types of experimental paradigms can be utilized to evaluate the possibility that rodents share positive affective experiences. Taken together, these studies were inspired by Jaak Panksepp’s theory that all mammals are capable of felt affective experiences.

Altered behavior and neural activity in conspecific cagemates co-housed with mouse models of brain disorders

“…Recent animal studies revealed that emotion contagion or empathy and prosocial behavior occur in rodents [56,[60][61][62][63][64][65][66][67][68][69][70]. Based on previous findings, we hypothesized that an unstable psychosocial environment could be created by housing mice long-term with murine models of brain disorders, and that certain psychosocial relationships between cagemates may be formed on account of abnormal behaviors of the mouse models and social interactions or emotional communication between cagemates.…”

Behavioral and mechanistic insight into rodent empathy

“…Conceptually, it ranges from simple emotional behaviors that include mimicry and emotional contagion to evolutionarily more complex constructs, such as perspective taking and targeted helping (see Preston and de Waal, 2002 for a review). In this review, we refer to "empathy" as the ability to share or relate to the affective state of another by considering aspects of emotional contagion, social modulation of learning and helping behaviors, all essential components of empathy that are within the capability of rodents (Panksepp and Panksepp, 2013;Panksepp and Lahvis, 2011). Since empathy behaviors have been observed in species ranging from mice to elephants, the debate should no longer be about whether animals have empathy;…”

Heightened emotional contagion in mild cognitive impairment and Alzheimer’s disease is associated with temporal lobe degeneration

“…Via salience network structures and emotion generators (26), emotions can unfold without conscious awareness (36) and travel rapidly from organism to organism through the activation of visceromotor mirroring mechanisms (36)(37)(38). With deep ontogenetic and phylogenetic roots, emotional contagion is present in human infants, birds, rodents, and nonhuman primates, among others (38,39). Human neonates display this rudimentary form of empathy and, from the first days of life, mimic facial expressions (40) and share others' distress, as demonstrated by studies in which infants cry more after hearing the cries of other infants (but not after hearing recordings of their own cries) (41).…”

“…Thus, emotional contagion is a simple form of affect sharing that is at the core of more sophisticated forms of empathy and is not dependent on higher-order cognitive processing. An ecologically valid index of empathic reactivity, emotional contagion can be examined across species and in laboratory settings (39) and can be used to investigate the integrity of neurobiological systems that support emotion.…”