Abstract
Purpose: :
Assess the spatial and temporal characteristics of vision in C57BL/6J mice
Methods: :
We measured contrast sensitivity of C57BL/6J mice using a behavioral measure of their optomotor responses (OptoMotry©). The stimuli consisted of vertical sinusoidal patterns rotating in a clockwise or counterclockwise direction. Using a double–blind procedure we measured both spatial transfer functions (STF) and temporal transfer functions (TTF) over a wide range of intensities (3.9 ×10–5 cd/m2 to 70 cd/m2).
Results: :
Under light adapted conditions, STF has an inverse–U shape with maximal sensitivity at 0.128 cyc/deg. As background illumination decreases, sensitivity decreases and its peak shifts to lower spatial frequencies. Similar to STF, the TTF has an inverse–U shape that depends on spatial frequency. At high spatial frequency (0.128 cyc/deg), contrast sensitivity peaks at 1.5 Hz. As background illumination decreases, sensitivity decreases and peaks at lower temporal frequencies (down to 0.4 Hz). At low spatial frequency (0.031 cyc/deg), contrast sensitivity peaks at 0.1 Hz and does not depend on background illumination levels.
Conclusions: :
Two pathways appear to transmit spatial and temporal properties of visual stimuli in mice. One is maximally sensitive to high spatial and temporal frequencies and dominates vision at photopic light levels. The other is most sensitive to lower spatial and temporal frequencies and operates at scotopic levels. The two pathways may reflect rod and cone inputs.
Keywords: contrast sensitivity • visual acuity