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Abstract:
Abstract: Neural correlates of successful episodic
recognition memory were explored in two studies. 32 subjects
studied words under intentional (study 1, N=14) or incidental
(study 2, N=18) encoding conditions. During imaging, subjects
viewed words and indicated whether they were old or new. Standard
event-related fMRI procedures were employed, using rapidly
presented trials (~2.5 sec apart) and intermixed fixation trials
(Buckner et al., 1998 Neuron). A network of brain areas including
commonly activated visual, frontal, and parietal regions were
observed when comparing recognition trials to fixation (Buckner et
al., 1998 NeuroImage). Analyses comparing hits to
correct-rejections (CR) demonstrated that medial parietal, lateral
parietal, and anterior left frontal cortex were more active for
hits. This converges with Donaldson et al. (abstract) and Henson et
al. (1999 J. Neurosci.), suggesting brain areas that are modulated
by successful retrieval. In study 2, correctly recognized items
were further subdivided based on whether prior study involved deep
or shallow encoding. Areas active for hits were most active
following deep encoding, consistent with the hypothesis that these
regions are associated with recollection. Notably, left parietal
cortex is modulated across item types that may rely most on
recollection (hits > CR in studies 1, 2 and Donaldson et
al.; deep hits > shallow hits in study 2; remember > new,
remember > know in Henson et al.).
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