title: Perceived helplessness is associated with individual differences in the central motor output system.
abstract: Learned helplessness is a maladaptive response to uncontrollable stress characterized by impaired motor escape responses, reduced motivation and learning deficits. There are important individual differences in the likelihood of becoming helpless following exposure to uncontrollable stress but little is known about the neural mechanisms underlying these individual differences. Here we used structural MRI to measure gray and white matter in individuals with chronic pain, a population at high risk for helplessness due to prolonged exposure to a poorly controlled stressor (pain). Given that self-reported helplessness is predictive of treatment outcomes in chronic pain, understanding such differences might provide valuable clinical insight. We found that the magnitude of self-reported helplessness correlated with cortical thickness in the supplementary motor area (SMA) and midcingulate cortex, regions implicated in cognitive aspects of motor behavior. We then examined the white matter connectivity of these regions and found that fractional anisotropy of connected white matter tracts along the corticospinal tract was associated with helplessness and mediated the relationship between SMA cortical thickness and helplessness. These data provide novel evidence that links individual differences in the motor output pathway with perceived helplessness over a chronic and poorly controlled stressor.
authors.affiliation: Division of Brain, Imaging and Behaviour - Systems Neuroscience, Toronto Western Research Institute, Toronto, ON, Canada.
authors.forename: Tim V
authors.initials: TV
authors.lastname: Salomons
authors.forename: Massieh
authors.initials: M
authors.lastname: Moayedi
authors.forename: Irit
authors.initials: I
authors.lastname: Weissman-Fogel
authors.forename: Michael B
authors.initials: MB
authors.lastname: Goldberg
authors.forename: Bruce V
authors.initials: BV
authors.lastname: Freeman
authors.forename: Howard C
authors.initials: HC
authors.lastname: Tenenbaum
authors.forename: Karen D
authors.initials: KD
authors.lastname: Davis
mesh_terms: D000328:Adult; D016880:Anisotropy; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006380:Helplessness, Learned; D006801:Humans; D007206:Individuality; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D010146:Pain / Q000209:etiology / Q000473:pathology*; D010147:Pain Measurement; D011336:Probability; D013705:Temporomandibular Joint Disorders / Q000150:complications / Q000473:pathology