The Roles of Dopamine and Serotonin in Decision Making: Evidence from Pharmacological Experiments in Humans

Abstract

Neurophysiological experiments in primates, alongside neuropsychological and functional magnetic resonance investigations in humans, have significantly enhanced our understanding of the neural architecture of decision making. In this review, I consider the more limited database of experiments that have investigated how dopamine and serotonin activity influences the choices of human adults. These include those experiments that have involved the administration of drugs to healthy controls, experiments that have tested genotypic influences upon dopamine and serotonin function, and, finally, some of those experiments that have examined the effects of drugs on the decision making of clinical samples. Pharmacological experiments in humans are few in number and face considerable methodological challenges in terms of drug specificity, uncertainties about pre-vs post-synaptic modes of action, and interactions with baseline cognitive performance. However, the available data are broadly consistent with current computational models of dopamine function in decision making and highlight the dissociable roles of dopamine receptor systems in the learning about outcomes that underpins value-based decision making. Moreover, genotypic influences on (interacting) prefrontal and striatal dopamine activity are associated with changes in choice behavior that might be relevant to understanding exploratory behaviors and vulnerability to addictive disorders. Manipulations of serotonin in laboratory tests of decision making in human participants have provided less consistent results, but the information gathered to date indicates a role for serotonin in learning about bad decision outcomes, non-normative aspects of risk-seeking behavior, and social choices involving affiliation and notions of fairness. Finally, I suggest that the role played by serotonin in the regulation of cognitive biases, and representation of context in learning, point toward a role in the cortically mediated cognitive appraisal of reinforcers when selecting between actions, potentially accounting for its influence upon the processing salient aversive outcomes and social choice.

Genetic Influences on Social Cognition

“…The serotonergic system is the largest efferent system in the brain. It has wide-ranging functions, including behavioral inhibition, appetite, aggression, mood, social affiliation, and sleep, in addition to social decision-making (73). In primate studies, experimentally elevated serotonin decreases aggression and increases cooperativeness and social potency.…”

Adult AMPA GLUA1 Receptor Subunit Loss in 5-HT Neurons Results in a Specific Anxiety-Phenotype with Evidence for Dysregulation of 5-HT Neuronal Activity

“…The dorsal and median raphe nuclei of the midbrain give rise to ascending projections that, due to their widespread distribution and extensive connectivity, are involved in many physiological processes underlying cognition, emotions, and perception (Cools et al, 2008;Heninger, 1997). These include the control of many complex behaviors such as aggression, impulsive behavior, decision making, responsiveness to punishment and aversive signaling or anxiety (Carver and Miller, 2006;Cools et al, 2008;Dayan and Huys, 2009;Lucki, 1998;Rogers, 2011). Accordingly, serotonergic dysregulation during development and/or adulthood has been associated with many psychiatric disorders with diverse psychopathology (Carver and Miller, 2006;Finger et al, 2007;Geyer and Vollenweider, 2008;Gordon and Hen, 2004;Mann, 2003;Pardo and Eberhart, 2007;Zill et al, 2004).…”

The Integration of Sociality, Monoamines, and Stress Neuroendocrinology in Fish Models: Applications in the Neurosciences

“…Monoaminergic systems modulate the activity of specific behavioural circuits which have been implicated in a plethora of functions, from cognition to emotional behaviour (Cools et al, 2007;Rogers, 2010). For vertebrates, a "social behaviour network" (SBN; Newman, 1999) has been proposed which overlaps a "mesolimbic reward system" to form a "social decision making network" (O'Connell & Hofmann, 2011a, 2011b, 2012.…”