Dopamine dependency of cognitive switching and response repetition effects in Parkinson's patients

Sheryl K. Shook, Elizabeth A. Franz, Christopher I. Higginson, Vicki L Wheelock, Karen A. Sigvardt

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


A group of people with Parkinson's disease and a group of matched controls were tested on a task involving a switch between perceptual dimensions. Patients were tested both 'on' and 'off' their normal medication cycles. Stimuli appeared in pairs for each trial, with each stimulus consisting of a color and a shape. One dimension of color and one of shape were mapped to each of two response keys. A cue was presented concurrently with each stimulus to indicate whether to respond on the basis of color or shape, following procedures developed by Hayes et al. [Hayes, A.E., Davidson, M.C., Keele, S.W., & Rafal, R.D. (1998). Toward a functional analysis of the basal ganglia. Journal of Cognitive Neuroscience, 10, 178-198]. Replicating previous literature, abnormally large switch costs were observed in patients who were off their normal medication cycles. A novel finding was that patients in the 'on' state demonstrated a slight reversal of switch costs. Also novel, reaction time (RT) costs associated with switching between response keys, and interactions between response switching and task switching were influenced predominantly by on-off dopamine manipulations. It is concluded that abnormal task switching costs and response repetition effects likely reflect impairments of activation and inhibition, and both effects are dopamine-dependent.

Original languageEnglish (US)
Pages (from-to)1990-1999
Number of pages10
Issue number14
StatePublished - 2005


  • Cognitive switching
  • Dopamine
  • Parkinson's disease
  • Response repetition

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Neuropsychology and Physiological Psychology


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