The Journal of Neuroscience, March 15, 2003, 23(6):2407
What Neural Correlates Underlie Successful Encoding and
Retrieval? A Functional Magnetic Resonance Imaging Study Using a
Divided Attention Paradigm
Elizabeth A.
Kensinger1,
Richard J.
Clarke1, and
Suzanne
Corkin1, 2
1 Department of Brain and Cognitive Sciences,
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and 2 Athinoula A. Martinos Center for Biomedical Imaging,
Charlestown, Massachusetts 02129
If attention is divided during learning, memory suffers.
Nevertheless, individuals can learn information with divided attention. This event-related functional magnetic resonance imaging (fMRI) study
(n = 17) investigated what neural processes support
(1) learning with divided attention and (2) retrieval of information learned with divided attention. Participants encoded words (Is the word
abstract or concrete?) while performing an auditory discrimination task
(press a button whenever an auditory pattern changes). The auditory
task was easy or hard, depending on the similarity of the patterns. A
behavioral study indicated that detailed ("recollective") information was more likely to be present for words encoded with the
easy versus the hard concurrent task. Words encoded with the hard
versus the easy concurrent task, in contrast, were more likely to rely
on less detailed ("familiarity"-based) information. fMRI revealed
encoding-related activation in the left prefrontal cortex (PFC) and
left hippocampus that was linked to successful memory formation only
for items encoded with the easy task. In contrast, activation in the
right PFC and left parahippocampal gyrus was linked to successful
memory for all items. Thus, successful encoding with the hard
concurrent task was supported by a subset of the regions recruited for
successful encoding with the easy task. The neural processes recruited
for successful retrieval also depended on the encoding condition: The
left PFC was disproportionately recruited for retrieval of items
encoded with the easy task, whereas the right PFC was
disproportionately recruited for retrieval of items encoded with the
hard task. These findings may reflect left-sided specialization for
recollective memories and right-sided specialization for
familiarity-based traces.
Key words:
divided attention; explicit memory; encoding; retrieval; dual task; neuroimaging; prefrontal cortex; human
Copyright © 2003 Society for Neuroscience 0270-6474/03/2362407-09$05.00/0
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