Changing patterns of brain activation during category learning revealed by functional MRI.
Functional magnetic resonance imaging (fMRI) was used to investigate neural changes as a function of category learning in normals (n=8). Subjects were trained to classify patterns of dots into four categories over 4 consecutive days. fMRI monitored the changes that occurred during learning prior to training and then following each training session. During fMRI, subjects determined whether two patterns of dots were members of the same category. The behavioral changes that occurred as a result of the training were observed as increases in response accuracy within shortened response times. fMRI illustrated initial increases in volumes of activation distributed across the known visuospatial processing networks. The regions affected by learning were identified as those involved in the planning and execution of eye movements (frontal and supplementary eye fields, FEF and SEF), spatial attention (superior and inferior parietal lobules, SPL and IPL) and visual processing (primary, secondary, and tertiary visual cortices). The volumes of activation then decreased as training progressed further. Of the two proposed mechanisms for learning, that of strengthened connectivity on a given network and that of selection of different networks, our data supports the former.
Little
Deborah M
DM
Center for Magnetic Resonance Research, College of Medicine, University of Illinois, Room 1193, MC 707, 1801 W. Taylor Street, Chicago, IL 60612, USA. little@uic.edu
Klein
Raymond
R
Shobat
Donna M
DM
McClure
Erik D
ED
Thulborn
Keith R
KR
D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011214:Practice, Psychological; D011930:Reaction Time; D013997:Time Factors
D010100:Oxygen