Central insulin modulates food valuation via mesolimbic pathways

Abstract

Central insulin is thought to act at the neural interface between metabolic and hedonic drives to eat. Here, using pharmacological fMRI, we show that intranasal insulin (INI) changes the value of food cues through modulation of mesolimbic pathways. Overnight fasted participants rated the palatability of food pictures and attractiveness of non-food items (control) after receiving INI or placebo. We report that INI reduces ratings of food palatability and value signals in mesolimbic regions in individuals with normal insulin sensitivity. Connectivity analyses reveal insulinergic inhibition of forward projections from the ventral tegmentum to the nucleus accumbens. Importantly, the strength of this modulation predicts decrease of palatability ratings, directly linking neural findings to behaviour. In insulin-resistant participants however, we observe reduced food values and aberrant central insulin action. These data demonstrate how central insulin modulates the cross-talk between homeostatic and non-homeostatic feeding systems, suggesting that dysfunctions of these neural interactions may promote metabolic disorders.

Motivated Cognition: Effects of Reward, Emotion, and Other Motivational Factors Across a Variety of Cognitive Domains

“…It has also been shown in a number of studies that words processed with their survival relevance in-mind are remembered better than in the context of several other instructions (Kang et al, 2008;Nairne et al, , 2007Soderstrom & McCabe, 2011;Weinstein et al, 2008). Food stimuli, briefly discussed as being used in both studies of emotion and reward, have also been studied in their own right as a means of probing motivational processes, particularly with interest in timevarying differences in motivation through satiation (Radel & Clément-Guillotin, 2012;Skrynka & Vincent, 2017;Wagner et al, 2012) and other measures of physiological homeostasis (Padulo et al, 2017;Tiedemann et al, 2017).…”

Upper airway stimulation in obstructive sleep apnea improves glucose metabolism and reduces hedonic drive for food

“…However, the consistent reduction in the hedonic drive to eat might reflect a decreased hedonic influence on appetite control that could be related at least in part to the potential reduction of insulin resistance upon UAS in our patients. We have shown previously that peripheral insulin resistance in subjects without diabetes determines the central nervous impact of insulin on hedonic but not homeostatic value of food (Tiedemann et al, 2017). In turn, improvement of peripheral insulin resistance by UAS might be the mechanistic link.…”

A review on insulin presence and function in brain

“…Insulin receptors are distributed across the reward circuit that suggests a modulatory role for this hormone in motivational aspects of food intake. 27 IRs are expressed on VTA neurons and studies have demonstrated insulin signaling cause increase in the reuptake of dopamine by VTA. 28 Intra-cerebral injection of insulin or hyperinsulinemia cause increase in dopamine transporter, DAT, mRNA in the VTA area.…”