title: Impaired implicit learning and feedback processing after stroke.
abstract: The ability to learn is assumed to support successful recovery and rehabilitation therapy after stroke. Hence, learning impairments may reduce the recovery potential. Here, the hypothesis is tested that stroke survivors have deficits in feedback-driven implicit learning. Stroke survivors (n=30) and healthy age-matched control subjects (n=21) learned a probabilistic classification task with brain activation measured using functional magnetic resonance imaging in a subset of these individuals (17 stroke and 10 controls). Stroke subjects learned slower than controls to classify cues. After being rewarded with a smiley face, they were less likely to give the same response when the cue was repeated. Stroke subjects showed reduced brain activation in putamen, pallidum, thalamus, frontal and prefrontal cortices and cerebellum when compared with controls. Lesion analysis identified those stroke survivors as learning-impaired who had lesions in frontal areas, putamen, thalamus, caudate and insula. Lesion laterality had no effect on learning efficacy or brain activation. These findings suggest that stroke survivors have deficits in reinforcement learning that may be related to dysfunctional processing of feedback-based decision-making, reward signals and working memory.
authors.affiliation: Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller Straße 27, 72076 Tübingen, Germany. Electronic address: judithmylinlam@gmail.com.
authors.forename: J M
authors.initials: JM
authors.lastname: Lam
authors.affiliation: Division of Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zürich, Frauenklinikstrasse 26, 8091 Zürich, Switzerland. Electronic address: cglobas@me.com.
authors.forename: C
authors.initials: C
authors.lastname: Globas
authors.affiliation: Division of Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zürich, Frauenklinikstrasse 26, 8091 Zürich, Switzerland. Electronic address: Jonas_Hosp@web.de.
authors.forename: J A
authors.initials: JA
authors.lastname: Hosp
authors.affiliation: Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller Straße 27, 72076 Tübingen, Germany; Department of Psychology, University of South Carolina, Columbia, SC 29016, USA; German Center of Neurodegenerative Diseases (DZNE), Hoppe-Seyler-Straße 3, 72076 Tübingen, Germany. Electronic address: karnath@uni-tuebingen.de.
authors.forename: H-O
authors.initials: HO
authors.lastname: Karnath
authors.affiliation: Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller Straße 27, 72076 Tübingen, Germany. Electronic address: tobias.waechter@uni-tuebingen.de.
authors.forename: T
authors.initials: T
authors.lastname: Wächter
authors.affiliation: Division of Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zürich, Frauenklinikstrasse 26, 8091 Zürich, Switzerland; Cereneo Center for Neurology and Rehabilitation, Vitznau, Switzerland. Electronic address: andreas.luft@uzh.ch.
authors.forename: A R
authors.initials: AR
authors.lastname: Luft
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology; D005260:Female; D000068156:Formative Feedback; D006801:Humans; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012054:Reinforcement, Psychology; D020521:Stroke / Q000473:pathology / Q000503:physiopathology*
keywords: classification learning; fMRI; feedback; reinforcement learning; reward; stroke