Temporal changes in neural activation during practice of information retrieval from short-term memory: an fMRI study.
Several findings indicate that practice in working memory tasks leads to signal decreases in task-relevant regions. However, the precise dynamics underlying these signal decreases and how they are correlated with improvements in behavioral performance are still matters of debate. We used functional magnetic resonance imaging (fMRI) to assess the cerebral correlates of the practice-related transition from controlled to automatic processing for the retrieval of information maintained in working memory storage. Exponential signal decreases and increases were modeled as covariates of interest. In addition, a bivariate regression analysis on the change in BOLD signal for two a priori hypothesized prefrontal regions (VLPFC, DLPFC) and the change in behavioral performance was conducted to examine the relationship between practice-related changes in cerebral activation and performance. We found exponential practice-related signal decreases mainly in the right superior frontal gyrus/DLPFC (BA 8/9/46), the middle frontal gyrus bilaterally (BA 10/11), the left precentral gyrus (BA 4/6) and the dorsal part of the right anterior cingulate cortex (BA 32). An exponential signal increase was detectable in the posterior cingulate cortex adjacent to the corpus callosum. In addition, there was a correlation between the practice-related change in BOLD signal in the DLPFC (BA 8/9) and the practice-related change in behavioral performance. These results suggest that the transition from controlled to automatic working memory processing is associated with exponential signal decreases in task-relevant regions. The temporal changes in brain activation patterns could be attributed to enhanced efficiency of information processing as a result of cognitive practice.
Koch
Kathrin
K
Department of Psychiatry, University of Jena, Philosophenweg 3, 07740 Jena, Germany.
Wagner
Gerd
G
von Consbruch
Katrin
K
Nenadic
Igor
I
Schultz
Christoph
C
Ehle
Christian
C
Reichenbach
Jürgen
J
Sauer
Heinrich
H
Schlösser
Ralf
R
D000328:Adult; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010100:Oxygen / Q000097:blood; D011214:Practice, Psychological; D011930:Reaction Time / Q000502:physiology
D010100:Oxygen