The neural correlates of implicit and explicit sequence learning: Interacting networks revealed by the process dissociation procedure.
In two H2(15)O PET scan experiments, we investigated the cerebral correlates of explicit and implicit knowledge in a serial reaction time (SRT) task. To do so, we used a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious contributions to performance during a subsequent sequence generation task. To manipulate the extent to which the repeating sequential pattern was learned explicitly, we varied the pace of the choice reaction time task-a variable that is known to have differential effects on the extent to which sensitivity to sequence structure involves implicit or explicit knowledge. Results showed that activity in the striatum subtends the implicit component of performance during recollection of a learned sequence, whereas the anterior cingulate/mesial prefrontal cortex (ACC/MPFC) supports the explicit component. Most importantly, we found that the ACC/MPFC exerts control on the activity of the striatum during retrieval of the sequence after explicit learning, whereas the activity of these regions is uncoupled when learning had been essentially implicit. These data suggest that implicit learning processes can be successfully controlled by conscious knowledge when learning is essentially explicit. They also supply further evidence for a partial dissociation between the neural substrates supporting conscious and nonconscious components of performance during recollection of a learned sequence.
Destrebecqz
Arnaud
A
Cognitive Science Research Unit, Université Libre de Bruxelles, B-1050 Belgium Cyclotron Research Center, University of Liège, Switzerland. adestre@ulb.ac.be
Peigneux
Philippe
P
Laureys
Steven
S
Degueldre
Christian
C
Del Fiore
Guy
G
Aerts
Joël
J
Luxen
André
A
Van Der Linden
Martial
M
Cleeremans
Axel
A
Maquet
Pierre
P
D000293:Adolescent; D000328:Adult; D001364:Awareness / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D002755:Choice Behavior / Q000502:physiology; D003243:Consciousness / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000502:physiology; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012691:Serial Learning / Q000502:physiology*; D014473:Unconscious, Psychology
D010104:Oxygen Radioisotopes