title: A dissociation between stopping and switching actions following a lesion of the pre-supplementary motor area.
abstract: BACKGROUND
  Although the pre-supplementary motor area (pre-SMA) is one of the most frequently reported areas of activation in functional imaging studies, the role of this brain region in cognition is still a matter of intense debate. Here we present a patient with a focal lesion of caudal pre-SMA who displays a selective deficit in updating a response plan to switch actions, but shows no impairment when required to withhold a response - stopping.
  
  
  METHODS
  The patient and a control group underwent three tasks designed to measure different aspects of cognitive control and executive function.
  
  
  RESULTS
  The pre-SMA patient displayed no impairment when responding in the face of distracting stimuli (Eriksen flanker paradigm), or when required to halt an on-going response (STOP task). However, a specific deficit was observed when she was required to rapidly switch between response plans (CHANGE task).
  
  
  CONCLUSIONS
  These findings suggest that the caudal pre-SMA may have a particularly important role in a network of brain regions required for rapidly updating and implementing response plans. The lack of any significant impairment on other measures of cognitive control suggests that this is not likely due to a global deficit in cognitive control. We discuss the implications of these results in the context of current theories of pre-SMA function.
authors.affiliation: Academic Department of Neuro-otology, Division of Brain Sciences, Imperial College London, London, UK. Electronic address: Ed.Roberts@imperial.ac.uk.
authors.forename: R Edward
authors.initials: RE
authors.lastname: Roberts
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Department of Experimental Psychology, University of Oxford, Oxford, UK.
authors.forename: Masud
authors.initials: M
authors.lastname: Husain
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009044:Motor Cortex / Q000293:injuries / Q000503:physiopathology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*
keywords: Cognitive control; Executive function; Frontal; Pre-SMA