title: Instability of visual error processing for sensorimotor adaptation in schizophrenia.
abstract: Saccadic adaptation can be used to study disturbances of sensory processing and motor learning. We investigated whether patients with schizophrenia can adjust saccadic amplitudes to account for an increase in visual error while the saccade is in flight, and whether they transfer this change to a visuo-manual localization task. Fourteen patients (mean 37.1 years) and 14 healthy controls (mean 35.1 years) performed 200 adaptation trials of 10° with target shifts of 4° in the outward direction. We determined the percent amplitude change during adaptation and adaptation speed. In addition, subjects localized a stimulus that was flashed 50 ms after saccade target onset to measure the transfer of change in visual space perception to visuo-manual coordination. Eye movements were recorded at 1000 Hz. Saccade amplitudes increased over adaptation trials by 11 % (p < 0.001) similarly in both groups. Amplitude variability during adaptation was higher in patients (1.06° ± 0.32°) than in controls (0.71° ± 0.14°; p = 0.001), while adaptation speed was slower in patients (0.02 ± 0.03) than in controls (0.11 ± 0.11; p = 0.01). Other pre- and post-adaptation saccade metrics did not differ between groups. The adaptation process shifted localization of the flashed target in the adaptation direction similarly in both groups. The use of error signals for the internal recalibration of sensorimotor systems and the transfer of this recalibration to visual space perception appear basically unimpaired in schizophrenia. Higher amplitude variability in patients suggests a certain instability of saccadic control in cerebellar systems. Patients seem to rely on visual error processing in frontal circuitry, resulting in slower adaptation speeds, despite unimpaired adaptation strength.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Muenster, Albert-Schweitzer-Campus 1, Geb. A9, 48149, Muenster, Germany. rebekka.lencer@ukmuenster.de.|Otto-Creutzfeldt Center for Cognitive and Behavioural Neuroscience, University of Muenster, Muenster, Germany. rebekka.lencer@ukmuenster.de.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Lencer
authors.affiliation: Department of Psychology, University of Muenster, Muenster, Germany.|Otto-Creutzfeldt Center for Cognitive and Behavioural Neuroscience, University of Muenster, Muenster, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Meermeier
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Muenster, Albert-Schweitzer-Campus 1, Geb. A9, 48149, Muenster, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Silling
authors.affiliation: Department of Psychology, University of Muenster, Muenster, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Gremmler
authors.affiliation: Department of Psychology, University of Muenster, Muenster, Germany.|Otto-Creutzfeldt Center for Cognitive and Behavioural Neuroscience, University of Muenster, Muenster, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Lappe
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009949:Orientation; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000150:complications*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Amplitude variability; Efference copy; Prediction error; Saccades; Visual space perception; Visuo-manual transfer