title: Modulation of error-sensitivity during a prism adaptation task in people with cerebellar degeneration.
abstract: Cerebellar damage can profoundly impair human motor adaptation. For example, if reaching movements are perturbed abruptly, cerebellar damage impairs the ability to learn from the perturbation-induced errors. Interestingly, if the perturbation is imposed gradually over many trials, people with cerebellar damage may exhibit improved adaptation. However, this result is controversial, since the differential effects of gradual vs. abrupt protocols have not been observed in all studies. To examine this question, we recruited patients with pure cerebellar ataxia due to cerebellar cortical atrophy (n = 13) and asked them to reach to a target while viewing the scene through wedge prisms. The prisms were computer controlled, making it possible to impose the full perturbation abruptly in one trial, or build up the perturbation gradually over many trials. To control visual feedback, we employed shutter glasses that removed visual feedback during the reach, allowing us to measure trial-by-trial learning from error (termed error-sensitivity), and trial-by-trial decay of motor memory (termed forgetting). We found that the patients benefited significantly from the gradual protocol, improving their performance with respect to the abrupt protocol by exhibiting smaller errors during the exposure block, and producing larger aftereffects during the postexposure block. Trial-by-trial analysis suggested that this improvement was due to increased error-sensitivity in the gradual protocol. Therefore, cerebellar patients exhibited an improved ability to learn from error if they experienced those errors gradually. This improvement coincided with increased error-sensitivity and was present in both groups of subjects, suggesting that control of error-sensitivity may be spared despite cerebellar damage.
authors: Department of Neurology, University of Tokyo Hospital, Tokyo, Japan; Department of Neurology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan; hanajima-tky@umin.ac.jp.
authors: Ritsuko
authors: R
authors: Hanajima
authors: Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland; and.
authors: Reza
authors: R
authors: Shadmehr
authors: Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Shinya
authors: S
authors: Ohminami
authors: Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan; Department of Neurology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan;
authors: Ryosuke
authors: R
authors: Tsutsumi
authors: Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Yuichiro
authors: Y
authors: Shirota
authors: Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Takahiro
authors: T
authors: Shimizu
authors: Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Nobuyuki
authors: N
authors: Tanaka
authors: Department of Neurology, University of Tokyo Hospital, Tokyo, Japan; Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Yasuo
authors: Y
authors: Terao
authors: Department of Neurology, University of Tokyo Hospital, Tokyo, Japan; Division of Neuroscience, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan;
authors: Shoji
authors: S
authors: Tsuji
authors: Department of Neurology, Fukushima Medical University, Fukushima, Japan.
authors: Yoshikazu
authors: Y
authors: Ugawa
authors: Dynamic Brain Network Laboratory, Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka, Japan; Department of Brain Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan;
authors: Motoaki
authors: M
authors: Uchimura
authors: Department of Neurophysiology, Juntendo University Graduate School of Medicine, Tokyo, Japan;
authors: Masato
authors: M
authors: Inoue
authors: Dynamic Brain Network Laboratory, Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka, Japan; Department of Brain Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan; Department of Neurophysiology, Juntendo University Graduate School of Medicine, Tokyo, Japan;
authors: Shigeru
authors: S
authors: Kitazawa
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000223:Adaptation, Psychological / Q000502:physiology; D000328:Adult; D000368:Aged; D001284:Atrophy; D002524:Cerebellar Ataxia / Q000503:physiopathology / Q000523:psychology; D003201:Computers; D030141:Feedback, Psychological / Q000502:physiology; D056228:Feedback, Sensory / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology; D007909:Lenses; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D013132:Spinocerebellar Degenerations / Q000503:physiopathology / Q000523:psychology; D014796:Visual Perception / Q000502:physiology
keywords: cerebellar cortex; cerebellum; degenerative ataxia