On the benefits of not trying: brain activity and connectivity reflecting the interactions of explicit and implicit sequence learning

Cereb Cortex. 2005 Jul;15(7):1002-15. doi: 10.1093/cercor/bhh201. Epub 2004 Nov 10.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / cytology
  • Brain / physiology*
  • Female
  • Frontal Lobe / cytology
  • Frontal Lobe / physiology
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Memory / physiology*
  • Neural Inhibition / physiology*
  • Neural Pathways
  • Serial Learning / physiology*
  • Temporal Lobe / cytology
  • Temporal Lobe / physiology
  • Thalamus / cytology
  • Thalamus / physiology