1 November 2006 Near-infrared imaging of fast intrinsic optical responses in visible light-activated amphibian retina
Author Affiliations +
J. of Biomedical Optics, 11(6), 064030 (2006). doi:10.1117/1.2393155
High performance functional imaging is needed for dynamic measurements of neural processing in retina. Emerging techniques for visual prosthesis also require advanced methodology for reliable validation of electromagnetic stimulation of the retina. Imaging of fast intrinsic optical responses associated with neural activation promises a variety of technical advantages over traditional single and multichannel electrophysiological techniques for these purposes, but the application of fast optical signals for neural imaging has been limited by low signal-to-noise ratio and high background light intensity. However, by using an optimized near-infrared probe light and improved optical system, we improve the optical signals substantially, allowing single pass measurements with approximately micron resolution. We image fast intrinsic optical responses with different optical modalities, i.e., bright field, dark field, and cross-polarization, from isolated retina activated by visible light stimulation. At single cell resolution, bright-field imaging discloses the maxima of optical responses ~5% dI/I, where dI is the dynamic optical change and I is the baseline light intensity. Dark-field imaging techniques further enhance the sensitivity of optical measurements, and show the maxima of optical responses exceeding 10% dI/I. Cross-polarized imaging provides optical sensitivity similar to dark-field imaging, but different patterns of neural activation are observed.
Xincheng Yao, John S. George, "Near-infrared imaging of fast intrinsic optical responses in visible light-activated amphibian retina," Journal of Biomedical Optics 11(6), 064030 (1 November 2006). http://dx.doi.org/10.1117/1.2393155


Visible radiation

Near infrared

Optical testing

Signal to noise ratio

Tissue optics

Image resolution


Back to Top