Arousal shapes motivation: an integrative framework for understanding motivational deficits

Motivational deficits are a core feature of psychiatric disorders like major depressive disorder and schizophrenia, contributing significantly to reduced levels of daily functioning and quality of life. While most mechanistic frameworks of motivational impairments emphasize difficulties in accurately representing the value of goals - typically linked to dysfunction in dopamine-mediated reward systems - emerging evidence suggests that these models may be incomplete. In particular, dysfunctional modulation of arousal states may play a critical and underappreciated role by impairing the mobilization of cognitive and physiological resources required for goal-directed behavior in individuals with motivational deficits. Here, we aim to bridge the gap between arousal and valuation processes by offering an initial proposal for an integrative framework capable of explaining how motivational deficits may arise from their maladaptive interactions. We do this by first outlining how arousal systems support motivated behavior at a neural and cognitive level in healthy individuals, followed by highlighting converging evidence of arousal dysregulation in individuals with mood and psychotic disorders. Based on this work, we extend existing frameworks of motivated behavior by integrating arousal dynamics in order to outline how disruptions in the dynamic modulation of arousal can directly interfere with the formation and updating of value representations. We also offer recommendations for experimental and computational approaches that are needed to further clarify the role of arousal dynamics in healthy and clinical populations. A causal exploration of these mechanisms could lead to a more fine-grained understanding of disrupted processes of motivated behavior across transdiagnostic dimensions of psychopathology.