title: On the benefits of not trying: brain activity and connectivity reflecting the interactions of explicit and implicit sequence learning.
abstract: Under certain circumstances, implicit, automatic learning may be attenuated by explicit memory processes. We explored the brain basis of this phenomenon in a functional magnetic resonance imaging (fMRI) study of motor sequence learning. Using a factorial design that crossed subjective intention to learn (explicit versus implicit) with sequence difficulty (a standard versus a more complex alternating sequence), we show that explicit attempts to learn the difficult sequence produce a failure of implicit learning and, in a follow-up behavioural experiment, that this failure represents a suppression of learning itself rather than of the expression of learning. This suppression is associated with sustained right frontal activation and attenuation of learning-related changes in the medial temporal lobe and the thalamus. Furthermore, this condition is characterized by a reversal of the fronto-thalamic connectivity observed with unimpaired implicit learning. The findings demonstrate a neural basis for a well-known behavioural effect: the deleterious impact of an explicit search upon implicit learning.
authors.affiliation: Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK. pcf22@cam.ac.uk
authors.forename: P C
authors.initials: PC
authors.lastname: Fletcher
authors.forename: O
authors.initials: O
authors.lastname: Zafiris
authors.forename: C D
authors.initials: CD
authors.lastname: Frith
authors.forename: R A E
authors.initials: RA
authors.lastname: Honey
authors.forename: P R
authors.initials: PR
authors.lastname: Corlett
authors.forename: K
authors.initials: K
authors.lastname: Zilles
authors.forename: G R
authors.initials: GR
authors.lastname: Fink
mesh_terms: D000328:Adult; D001921:Brain / Q000166:cytology / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000166:cytology / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways; D012691:Serial Learning / Q000502:physiology*; D013702:Temporal Lobe / Q000166:cytology / Q000502:physiology; D013788:Thalamus / Q000166:cytology / Q000502:physiology