Journal of Neuroscience, Vol 9, 4111-4121, Copyright © 1989 by Society for Neuroscience
Resolution of metabolic columns by a double-label 2-DG technique: interdigitation and coincidence in visual cortical areas of the same monkey
HR Friedman, CJ Bruce and PS Goldman-Rakic
Section of Neuroanatomy, Yale University School of Medicine, New Haven, Connecticut 06510.
A double-label modification of the 2-deoxyglucose (DG) technique uses both
3H-2-DG and 14C-2-DG and allows for metabolic activity engaged by 2
distinct experimental conditions to be dissociated throughout the brain of
a single subject. In the present study, we used this double- label method
to examine the relationship between metabolic columns subserving the 2 eyes
in cortical visual areas V1 and V2. The left and right eye's ocular
dominance columns were separately activated in the same monkey to
demonstrate that the double-label 2-DG method can resolve metabolic
differences at the level of the cortical column. In 2 monkeys, 14C-2-DG was
injected first and one eye was occluded while the other eye was visually
stimulated for 30 min. Then 3H-2-DG was injected, and the occluder was
switched so that the alternate eye was stimulated with the same pattern for
30 min. Autoradiographs depicting the 2 labels separately were obtained by
exploiting the differential sensitivity of X-ray film and Ultrofilm to 3H
and 14C emissions and by applying a radioactivity-subtraction algorithm to
pairs of digitized images of the same section (Friedman et al., 1987).
Columnar regions of increased activity were evident throughout V1,
excepting the representations of the optic disk and monocular crescent.
Superimposition of the 3H and 14C images from the same sections
demonstrated that columns of increased 3H label were interdigitated with
columns of increased 14C label in V1. In contrast, bands of increased
3H-2-DG uptake in extrastriate area V2 were largely coincident with the
bands of increased 14C-2-DG uptake. These results illustrate the value of
the double-label 2-DG technique for studying fluctuations of metabolic
activity under different experimental conditions in the same subject. In
the present example, the demonstration that ocular dominance columns are
interdigitated in V1, whereas metabolically active bands are coincident in
V2, would not have been fully appreciated by comparing 2-DG labeling across
separate animals.
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