title: Fronto-striatal contribution to lexical set-shifting.
abstract: Fronto-striatal circuits in set-shifting have been examined in neuroimaging studies using the Wisconsin Card Sorting Task (WCST) that requires changing the classification rule for cards containing visual stimuli that differ in color, shape, and number. The present study examined whether this fronto-striatal contribution to the planning and execution of set-shifts is similar in a modified sorting task in which lexical rules are applied to word stimuli. Young healthy adults were scanned with functional magnetic resonance imaging while performing the newly developed lexical version of the WCST: the Wisconsin Word Sorting Task. Significant activation was found in a cortico-striatal loop that includes area 47/12 of the ventrolateral prefrontal cortex (PFC), and the caudate nucleus during the planning of a set-shift, and in another that includes the posterior PFC and the putamen during the execution of a set-shift. However, in the present lexical task, additional activation peaks were observed in area 45 of the ventrolateral PFC area during both matching periods. These results provide evidence that the functional contributions of the various fronto-striatal loops are not dependent on the modality of the information to be manipulated but rather on the specific executive processes required.
authors.affiliation: Functional Neuroimaging Unit, Institut Universitaire de Gériatrie de Montréal, Quebec, Canada.
authors.forename: France
authors.initials: F
authors.lastname: Simard
authors.forename: Yves
authors.initials: Y
authors.lastname: Joanette
authors.forename: Michael
authors.initials: M
authors.lastname: Petrides
authors.forename: Thomas
authors.initials: T
authors.lastname: Jubault
authors.forename: Cécile
authors.initials: C
authors.lastname: Madjar
authors.forename: Oury
authors.initials: O
authors.lastname: Monchi
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology*; D003342:Corpus Striatum / Q000033:anatomy & histology / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000502:physiology*; D013647:Task Performance and Analysis; D014705:Verbal Behavior / Q000502:physiology*; D055815:Young Adult