We study how the nervous
system works - how it is built, how it operates on cellular and systems
levels, how drugs affect it, and how it is damaged in neurodegenerative
diseases.
Our methods are as broad as our
questions, and include molecular, genetic, physiological and anatomical
techniques. We often work collaboratively and train students at the
graduate, post-doctoral and college levels.
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A new method
for imaging brain activity
Neuronal mitochondria give
high resolution images of neuronal activity patterns
September 21, 2007. A
picture is worth a thousand single-units. Understanding the details of
brain activity has, for nearly 50 years, relied predominantly on
recording electrical activity from one or a few neurons at a time. Over
the last 20 years, however, methods for imaging brain activity patterns
have become progressively better at revealing the fine nuances of
neural processing.
A new study from the Issa lab in the August
8th issue of the Journal of Neuroscience takes brain imaging to a new
level. Husson et al. report a method for imaging brain activity in
large mammals with high resolution and without the need for extrinsic
dyes.
The method, flavoprotein
autofluorescence imaging, relies on proteins in neuronal mitochondria
that fluoresce in response to increased energy demand, such as during
the firing of action potentials. The mitochondrial location of the
fluorophore conveys several advantages, among them a theoretical
sub-cellular spatial resolution and specificity to neurons rather than
glia.
The authors show that this
mitochondrial signal is preferable in several ways to standard imaging
techniques that rely on blood flow and blood oxygenation (BOLD signal).
Specifically, compared to the current gold standard in high-resolution
functional imaging (intrinsic signal imaging), autofluorescence has
better temporal and spatial resolution, substantially reduced vascular
artifacts, and reduced need for image filtering.
While autofluorescence has been
recently used to image rodent brains, work by other groups suggested it
couldn't be applied to larger brains - precluding its use in humans.
The new research, funded by the Brain Research Foundation and the
Mallinckrodt Foundation, suggests that the technique holds promise for
high-resolution human brain imaging. Because there is no need for dyes
or other extraneous compounds, there is no risk for toxic reactions
during imaging. As a result, it has potential as a diagnostic tool for
both functional disorders of the brain as well as for identification of
pathological tissue without resection.
More Information:
Husson, T.,
Mallik, A.K., Zhang, J., Issa, N.P. Functional Imaging of Primary
Visual Cortex Using Flavoprotein Autofluorescence. J. Neurosci. 2007,
27:8665-8675.
The
Issa Lab Website
The
Brain Research Foundation
For other departmental spotlights, see our Research
Archive.
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Congratulations
We are delighted
to announce the promotion of Dr.
Xiaoxi Zhuang to Associate Professor in the Department of
Neurobiology.
Dr. Zhuang studies the molecular
machinery for information processing in the dopamine system and in the
basal ganglia.
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