Comparatively reduced blood flow to frontal brain regions in patients with
schizophrenia (hypofrontality) has been frequently observed in the last 25
years. However, there is an inconstant quality to hypofrontality, suggestin
g either confounded observation of a static (trait-like) abnormality, or th
at it is a genuinely dynamic (state-like) phenomenon. Possible confounds in
functional magnetic resonance imaging (fMRI) studies of hypofrontality are
classified. Methods for assessment and correction of stimulus correlated m
otion (an extracerebral confound) are reviewed in the context of fMRI data
acquired from five schizophrenic patients and five comparison subjects duri
ng performance of a verbal fluency task. Factorial analysis of these and ot
her data, acquired from the same subjects during a semantic decision task,
is used to exclude a number of possible intracerebral confounds. By analogy
to the historical controversy concerning the appearance of the planet Satu
rn viewed through early telescopes, understanding the inconstancy of hypofr
ontality in schizophrenia is likely to progress more by theoretically drive
n experiments that exploit the repeatability of fMRI than by further techno
logical development alone. (C) 1999 Wiley-Liss, Inc.