We have recently reported (Saykin et al., 1999b) selective
activation of left medial temporal lobe structures during
processing of novel compared to familiar words using
functional magnetic resonance imaging (fMRI). The current
study describes the relationship between a widely used
clinical test of verbal learning, the California Verbal
Learning Test (CVLT), and the previously reported fMRI
activations. Thirteen right-handed healthy adult participants
were studied with whole brain echo-planar fMRI while listening
to novel and recently learned (familiar) words intermixed
pseudorandomly in an event-related design. These participants
were also tested with the CVLT. Scores for CVLT Trial 1
(immediate encoding of novel words) and recognition discriminability
(recognition of familiar vs. novel words) were
correlated with fMRI signal change during processing of
novel versus familiar words using a covariance
model implemented in SPM96. For the novel words analysis,
voxels in the right anterior hippocampus correlated significantly
with Trial 1 (r = .76 at the maxima). For the
recognition analysis, a significant cluster of voxels was
found in the right dorsolateral prefrontal cortex (r
= .88 at the maxima). Our prior results of separable left
medial temporal activation to novel and familiar words,
together with results of the covariance analyses reported
here, suggest that in addition to the left medial temporal
lobe (MTL) regions that are engaged during novel and familiar
word processing, the right hippocampus and right frontal
lobe are also involved, particularly in those participants
with better memory ability. This positive relationship
between fMRI activation and CVLT performance suggests a
role for these right hemisphere regions in successful memory
processing of verbal material, perhaps reflecting more
efficient encoding and retrieval strategies that facilitate
memory. (JINS, 2001, 7, 55–62.)