title: Effort Deficits and Depression: The Influence of Anhedonic Depressive Symptoms on Cardiac Autonomic Activity During a Mental Challenge.
abstract: Motivational approaches to depression emphasize the role of dysfunctional motivational dynamics, particularly diminished reward and incentive processes associated with anhedonia. A study examined how anhedonic depressive symptoms, measured continuously across a wide range of severity, influenced the physiological mobilization of effort during a cognitive task. Using motivational intensity theory as a guide, we expected that the diminished incentive value associated with anhedonic depressive symptoms would reduce effort during a "do your best" challenge (also known as an unfixed or self-paced challenge), in which effort is a function of the value of achieving the task's goal. Using impedance cardiography, two cardiac autonomic responses were assessed: pre-ejection period (PEP), a measure of sympathetic activity and our primary measure of interest, and respiratory sinus arrhythmia (RSA), a measure of parasympathetic activity. As expected, PEP slowed from baseline to task as anhedonic depressive symptoms increased (as measured with the DASS Depression scale), indicating diminished effort-related sympathetic activity. No significant effects appeared for RSA. The findings support motivational intensity theory as a translational model of effort processes in depression and clarify some inconsistent effects of depressive symptoms on effort-related physiology found in past work.
authors.affiliation: Department of Psychology, University of North Carolina at Greensboro.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Silvia
authors.affiliation: Department of Psychology, University of North Carolina at Greensboro.
authors.forename: Emily C
authors.initials: EC
authors.lastname: Nusbaum
authors.affiliation: Department of Psychology, University of North Carolina at Greensboro.
authors.forename: Kari M
authors.initials: KM
authors.lastname: Eddington
authors.affiliation: Department of Psychology, University of North Carolina at Greensboro.
authors.forename: Roger E
authors.initials: RE
authors.lastname: Beaty
authors.affiliation: Department of Psychology, University of North Carolina at Greensboro.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Kwapil
keywords: anhedonia; autonomic nervous system; depression; effort; impedance cardiography; motivational intensity