Selective impairments in implicit learning in Parkinson's disease

• Published in: Brain research Vol. 1137; no. 1; pp. 104 - 110
• Main Authors: Seidler, R.D, Tuite, P, Ashe, J
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 16.03.2007; Amsterdam Elsevier; New York, NY
• Subjects: Adult and adolescent clinical studies; Aged; Analysis of Variance; Biological and medical sciences; Case-Control Studies; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Functional Laterality - physiology; Humans; Implicit; Learning Disorders - etiology; Male; Medical sciences; Middle Aged; Neurology; Neuropsychological Tests; Organic mental disorders. Neuropsychology; Parkinson Disease - complications; Parkinson's disease; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reaction Time - physiology; Sequence learning; Serial Learning - physiology; Serial reaction time; Serial reaction time; Parkinson's disease; Implicit; Sequence learning; Human; Nervous system diseases; Parkinson disease; Cognition; Cerebral disorder; Acquisition process; Central nervous system disease; Degenerative disease; Implicit learning; Extrapyramidal syndrome
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2006.12.057

Abstract The basal ganglia are thought to participate in implicit sequence learning. However, the exact nature of this role has been difficult to determine in light of the conflicting evidence on implicit learning in subjects with Parkinson's disease (PD). We examined the performance of PD subjects using a modified form of the serial reaction time task, which ensured that learning remained implicit. Subjects with predominantly right-sided symptoms were trained on a 12-element sequence using the right hand. Although there was no evidence of sequence learning on the basis of response time savings, the subjects showed knowledge of the sequence when performance was assessed in terms of the number of errors made. This effect transferred to the left (untrained) hand as well. Thus, these data demonstrate that PD patients are not impaired at implicitly learning sequential order, but rather at the translation of sequence knowledge into rapid motor performance. Furthermore, the results suggest that the basal ganglia are not essential for implicit sequence learning in PD.