The metabolic mind: A role for leptin and ghrelin in affect and social cognition

Abstract

Leptin and ghrelin are metabolic hormones central to energy regulation in the body. Theories of allostasis suggest that metabolism could matter for more than just food intake and weight regulation but also ultimately for psychological processes, such as affect and social cognition. Allostasis is the process by which the brain monitors ongoing physiological states and, in turn, regulates physiology based on expectations about how a given situation will impact the self. Motivated by this allostatic perspective, we argue that leptin and ghrelin may be influenced by and even contribute to psychological processes such as affect and social cognition. Specifically, we review literature suggesting that leptin and ghrelin may be sensitive to social affective signals and related contexts (e.g., social status, and social threat vs. support), given that these signals and contexts may represent access to tangible physical and psychological resources that support allostasis and metabolic needs. We then review literature showing that leptin, ghrelin, and associated metabolic states may feed into the construction of social affective states and behaviors (e.g., emotion and risk taking), in order to motivate behaviors in line with allostatic needs. We close by offering guidelines for researchers interested in contributing to this emerging field and highlight opportunities for future research. We believe that leptin and ghrelin offer exciting new directions for social and affective scientists interested in linking the mind, brain, and body.

Affect in the Aging Brain: A Neuroimaging Meta-Analysis of Older Vs. Younger Adult Affective Experience and Perception

“…The theory of maturational dualism suggests that these structural changes may result in a disconnect between peripheral signals and mental processes such as affect and cognition Mendes, 2010;Mikkelsen et al, 2019). Although it is debated whether peripheral signals are necessary for affective experience (Barrett, 2017;Barrett & Bliss-Moreau, 2009;Berntson, Gianaros, & Tsakiris, 2018;Cannon, 1927;Ekman & Cordaro, 2011;Feinstein et al, 2016;Friedman, 2010;Garfinkel & Critchley, 2013;Harrison, Gray, Gianaros, & Critchley, 2010;MacCormack & Lindquist, 2017), there is increasing experimental evidence that ongoing efferent signals to and afferent signals from the body can indeed contribute to the quality of affective experiences and perceptions (Durso, Luttrell, & Way, 2015;Eisenberger, Moieni, Inagaki, Muscatell, & Irwin, 2017;Garfinkel et al, 2014;Gray et al, 2012;MacCormack et al, 2020;MacCormack & Muscatell, 2019;Muscatell et al, 2016).…”

Metabolic proteins at birth predict early childhood mental health symptoms

“…Aberrations in metabolism alter energy availability signaling, which we argue is a component of psychopathology (MacCormack & Muscatell, 2019). It is possible that by modulating energy availability, metabolic proteins affect social behavior and affect, which are both implicated in mental health symptoms.…”

“…We propose that some mental health symptoms can be conceptualized as energy dysregulation. Hypomania, hyperactivity, and mania are associated with an "influx" of energy, whereas depressive and anxiety symptoms conflate with "low" energy (MacCormack & Muscatell, 2019). From an evolutionary biology perspective, this is adaptive.…”

Lower Socioeconomic Position Is Associated with Greater Activity in and Integration within an Allostatic-Interoceptive Brain Network in Response to Affective Stimuli

“…Two brain networks whose properties may be particularly likely to be modulated by SEP are the "allostatic-interoceptive network" [AIN; (Kleckner et al, 2017;Wei et al, 2020;Kraft & Kraft, 2021;MacCormack & Muscatell, 2019)] and the "executive control network" [ECN; (Rosen et al, 2018;Yaple & Yu, 2020;Rakesh et al, 2021)]. The AIN is composed of the salience and default mode intrinsic networks and a set of subcortical regions (i.e., central nucleus of the amygdala and regions within the ventral and dorsal striatum, such as the periaqueductal gray, parabrachial nucleus, and nucleus of the solitary tract) and has been shown to subserve energy metabolism and visceromotor regulation (Kleckner et al, 2017).…”