Deficits in inhibitory control and conflict resolution on cognitive and motor tasks in Parkinson’s disease

• Published in: Experimental brain research 2011-07, Vol.212 (3), p.371-384
• Main Authors: Obeso, Ignacio, Wilkinson, Leonora, Casabona, Enrique, Bringas, Maria Luisa, Álvarez, Mario, Álvarez, Lázaro, Pavón, Nancy, Rodríguez-Oroz, Maria-Cruz, Macías, Raúl, Obeso, Jose A., Jahanshahi, Marjan
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cognition - physiology; Complications and side effects; Conflict, Psychological; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Fundamental and applied biological sciences. Psychology; Humans; Inhibition, Psychological; Male; Medical sciences; Middle Aged; Motor ability; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Movement disorders; Neurology; Neuropsychological Tests; Neurosciences; Parkinson Disease - physiopathology; Parkinson Disease - psychology; Parkinson's disease; Physiological aspects; Psychomotor Performance - physiology; Reaction time; Reaction Time - physiology; Research Article; Stroop Test; Subthalamic Nucleus - physiopathology; Vertebrates: nervous system and sense organs
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-011-2736-6

Recent imaging studies in healthy controls with a conditional stop signal reaction time (RT) task have implicated the subthalamic nucleus (STN) in response inhibition and the pre-supplementary motor area (pre-SMA) in conflict resolution. Parkinson’s disease (PD) is characterized by striatal dopamine deficiency and overactivity of the STN and underactivation of the pre-SMA during movement. We used the conditional stop signal RT task to investigate whether PD produced similar or dissociable effects on response initiation, response inhibition and response initiation under conflict. In addition, we also examined inhibition of prepotent responses on three cognitive tasks: the Stroop, random number generation and Hayling sentence completion. PD patients were impaired on the conditional stop signal reaction time task, with response initiation both in situations with or without conflict and response inhibition all being significantly delayed, and had significantly greater difficulty in suppressing prepotent or habitual responses on the Stroop, Hayling and random number generation tasks relative to controls. These results demonstrate the existence of a generalized inhibitory deficit in PD, which suggest that PD is a disorder of inhibition as well as activation and that in situations of conflict, executive control over responses is compromised.