Purpose:
To develop a variant of the functional intrinsic signal imaging method for mouse retina and compare the baseline characteristics with those observed in other species.
Methods:
The retinae of anesthetized mice were imaged with a custom retinal camera. A dim near-infrared light (NIR, 700-900nm) illuminated the retina while a CCD camera captured the changes in NIR reflectance of the retina. Patterned visual stimuli were projected into the subject's eye in randomized block-trials.
Results:
Spatially-specific changes in NIR reflectance correlated with the presented visual stimuli were observed in mouse retina. These imaged signals exhibited properties similar to those previously reported in other species (e.g. cat, monkey), including similar sign (negative, reflectance decrease), amplitude (~0.1%) and time course (rise time of seconds). Their spectral dependence also mirrored results from other species that, along with other measurements, suggest a dominant rod contribution.
Conclusions:
This novel functional imaging technique in mouse retina has demonstrated stimulus-driven reflectance change signals similar to those observed in the macaque monkey and cat retina. Future studies using particular knockout mouse models promise to help determine the anatomic and biophysical origins of these optical signals. Such studies may also yield important results relevant to human diseases of the retina.
Keywords: retina: distal (photoreceptors, horizontal cells, bipolar cells) • photoreceptors • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)