title: Prefrontal lesions impair the implicit and explicit learning of sequences on visuomotor tasks.
abstract: OBJECTIVE
  (1) To verify whether the prefrontal cortex (PFC) is specifically involved in visuomotor sequence learning as opposed to other forms of motor learning and (2) to establish the role of executive functions in visuomotor sequence learning.
  
  
  BACKGROUND
  Visuomotor skill learning depends on the integrity of the premotor and parietal cortex; the prefrontal cortex, however, is essential when the learning of a sequence is required.
  
  
  METHODS
  We studied 25 patients with PFC lesions and 86 controls matched for age and educational level. Participants performed: (1) a Pursuit Tracking Task (PTT), composed of a random tracking task (perceptual learning) and a pattern tracking task (explicit motor sequence learning with learning indicated by the decrease in mean root square error across trial blocks), (2) a 12-item sequence version of a serial reaction time task (SRTT) with specific implicit motor sequence learning indicated by the rebound increase in response time when comparing the last sequence block with the next random block, and (3) a neuropsychological battery that assessed executive functions.
  
  
  RESULTS
  PFC patients were impaired in sequence learning on the pattern tracking task of the PTT and on the SRTT as compared to controls, but performed normally on the PTT random tracking task. Learning on the PTT did not correlate with learning on the SRTT. PTT performance correlated with planning functions while SRTT performance correlated with working memory capacity.
  
  
  CONCLUSIONS
  The PFC is specifically involved in explicit and implicit motor sequence learning. Different PFC regions may be selectively involved in such learning depending on the cognitive demands of the sequential task.
authors.affiliation: Servicio de Neurologia, Hospital de Galdacano, 48960 Galdacano, Vizcaya, Spain. mgomezab@sarenet.es
authors.forename: Marian
authors.initials: M
authors.lastname: Gomez Beldarrain
authors.forename: Jordan
authors.initials: J
authors.lastname: Grafman
authors.forename: Ibone
authors.initials: I
authors.lastname: Ruiz de Velasco
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
authors.forename: Carlos
authors.initials: C
authors.lastname: Garcia-Monco
authors.forename: Jordan
authors.initials: J
authors.lastname: Gafman
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D017397:Prefrontal Cortex / Q000502:physiology / Q000503:physiopathology*; D011596:Psychomotor Disorders / Q000503:physiopathology / Q000523:psychology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012691:Serial Learning / Q000502:physiology*; D018709:Statistics, Nonparametric