Dynamic imaging of somatosensory cortical activity in the rat visualized by flavoprotein autofluorescence
We used autofluorescence of mitochondrial flavoproteins to image cortical neural activity in the rat. Green autofluorescence in blue light was examined in slices obtained from rat cerebral cortex. About half of the basal autofluorescence was modulated by the presence or absence of O 2 or glucose in...
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Published in: | The Journal of physiology Vol. 549; no. 3; pp. 919 - 927 |
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Main Authors: | , , , , , , , , |
Format: | Journal Article |
Language: | English |
Published: |
Oxford, UK
The Physiological Society
15-06-2003
Blackwell Publishing Ltd Blackwell Science Inc |
Subjects: | |
Online Access: | Get full text |
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Summary: | We used autofluorescence of mitochondrial flavoproteins to image cortical neural activity in the rat. Green autofluorescence
in blue light was examined in slices obtained from rat cerebral cortex. About half of the basal autofluorescence was modulated
by the presence or absence of O 2 or glucose in the medium. Repetitive electrical stimulation at 20 Hz for 1 s produced a localized fluorescence increase in
the slices. The amplitude of the increase was 27 ± 2 % (mean ± s.d. , n = 35). Tetrodotoxin or diphenyleneiodonium, an inhibitor of flavoproteins, blocked the autofluorescence responses. The autofluorescence
responses were not observed in slices perfused with calcium-, glucose- or O 2 -free medium. In the primary somatosensory cortex of rats anaesthetized with urethane (1.5 g kg â1 , i.p. ), an activity-dependent increase in autofluorescence of 20 ± 4 % ( n = 6) was observed after electrical cortical stimulation at 100 Hz for 1 s, and an increase of 2.6 ± 0.5 % ( n = 33) after vibratory skin stimulation at 50 Hz for 1 s applied to the plantar hindpaw. These responses were large enough
to allow visualization of the neural activity without having to average a number of trials. The distribution of the fluorescence
responses after electrical or vibratory skin stimulation was comparable to that of the cortical field potentials in the same
rats. The fluorescence responses were followed by an increase in arterial blood flow. The former were resistant to an inhibitor
of nitric oxide synthase, while the latter was inhibited. Thus, activity-dependent changes in the autofluorescence of flavoproteins
are useful for functional brain imaging in vivo . |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2003.040709 |