Purchase this article with an account.
WH Ridder, S Nusinowitz; Sweep VEP (sVEP) Acuity In Mice . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1802.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: The visual acuities of mice have been determined psychophysically and with pattern VEPs to be about 0.6 cpd. However, these techniques are time consuming to obtain acuity estimates. sVEPs are a more efficient method to determine visual acuity but they have not been recorded in mice. The purpose of this study was to determine if sVEPs can be measured in mice to determine acuity. Methods: Five mice (C57Bl/6J) were used in this experiment. Anesthesia was produced with a mixture of ketamine and xylazine (15 ug/g body weight:7 ug/g body weight) injected IP. The active electrode was a stainless steel bolt implanted 3 mm lateral to the lambda. The tip of the bolt rested on the dura. The reference electrode was a gold wire placed against the roof of the mouth and the ground was a needle under the skin near the tail. The mouse was placed in a stereotaxic (Stoelting, USA) apparatus that held the snout. Stimulus production and data collection were carried out with the Enfant (Neuroscientific Corp) system. The stimulus was a horizontally oriented sine wave grating. The sweep consisted of eleven spatial frequencies (0.10, 0.12, 0.16, 0.20, 0.25, 0.32, 0.40, 0.50, 0.63, 0.80, and 0.98 cpd). The stimulus contrast was 80% and the temporal reversal rate (square wave) was 4 Hz. The screen luminance was 100 cd/m2 and the screen subtended 100 (H) by 82 (V) at the mouse eye. Each spatial frequency was presented for 1 second so that the entire sweep took 12 seconds (11 spatial frequencies + 1 second pre-adaptation). Sweeps were averaged until the error bars for the data were stable. Results: The amplitude of the response (i.e., the second harmonic of the discrete Fourier transform) was plotted against spatial frequency. Acuity was determined by: 1. extrapolating the high spatial frequency data to the X-axis (N = 2) or 2. taking the highest spatial frequency above noise that produced a reliable response (N = 3). The average acuity for the mice was 0.76 +/- 0.079 cpd (mean +/- SD). This corresponds to an acuity of 20/789 and agrees with previous acuity estimates for mice. Conclusion: sVEPs are a fast, reliable means of obtaining visual acuity in mice.
This PDF is available to Subscribers Only