Optical Mapping
Observing the phenomena in coupled oscillator and excitable media systems
requires equipment that can simultaneously record signals from many spatial
points at one time. In some systems, such as the BZ reaction and slime mold aggregation,
wave propagation is visible to the naked eye and is slow enough to allow use of conventional
camera equipment. Other systems, such as electrical propagation in cardiac and neural tissue,
occur at fast time scales without visual queues. The importance of spatio-temporal patterns in
biology has driven development of sophisticated imaging techniques.
All optical mapping studies involve specialized illumination and detection apparatus.
In most studies, stained samples are illuminated over a relatively large area. Appropriate
sources of illumination vary with the characteristics of the dye used, but is usually
a tungsten halogen or mercury arc lamp fitted with appropriate filters to select optimal excitation
wavelengths. Fluorescent light from the preparation is filtered to remove background reflected light.
A detector with multiple elements, such as a photodiode array or CCD, is placed in the
objective image plane and detects the signal of interest. The image is then signal processed and stored.
The optical imaging lab in the Physiology Department at
McGill University is supervised
by Dr. Alvin Shrier and
Dr. Leon Glass. The optical apparatus was designed and constructed by
myself (see here for details),
and has been maintained and improved by several researchers, most notably Dr. Tiger Nagai
and Dr. Katsumi Tateno.The imaging
setup can map voltage and calcium ion concentrations in cultured or whole cardiac preparations
at macroscopic and microscopic space scales.
This site showcases some of the optical mapping work I've done on monolayers of cultured cardiac cells. To continue,
check the links below...
