The mouse model of Down syndrome Ts65Dn presents visual deficits as assessed by pattern visual evoked potentials.
OBJECTIVE
The Ts65Dn mouse is the most complete widely available animal model of Down syndrome (DS). Quantitative information was generated about visual function in the Ts65Dn mouse by investigating their visual capabilities by means of electroretinography (ERG) and patterned visual evoked potentials (pVEPs).


METHODS
pVEPs were recorded directly from specific regions of the binocular visual cortex of anesthetized mice in response to horizontal sinusoidal gratings of different spatial frequency, contrast, and luminance generated by a specialized video card and presented on a 21-in. computer display suitably linearized by gamma correction.


RESULTS
ERG assessments indicated no significant deficit in retinal physiology in Ts65Dn mice compared with euploid control mice. The Ts65Dn mice were found to exhibit deficits in luminance threshold, spatial resolution, and contrast threshold, compared with the euploid control mice. The behavioral counterparts of these parameters are luminance sensitivity, visual acuity, and the inverse of contrast sensitivity, respectively.


CONCLUSIONS
DS includes various phenotypes associated with the visual system, including deficits in visual acuity, accommodation, and contrast sensitivity. The present study provides electrophysiological evidence of visual deficits in Ts65Dn mice that are similar to those reported in persons with DS. These findings strengthen the role of the Ts65Dn mouse as a model for DS. Also, given the historical assumption of integrity of the visual system in most behavioral assessments of Ts65Dn mice, such as the hidden-platform component of the Morris water maze, the visual deficits described herein may represent a significant confounding factor in the interpretation of results from such experiments.
Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
Jonah Jacob
JJ
Scott-McKean
Bo
B
Chang
Ronald E
RE
Hurd
Steven
S
Nusinowitz
Cecilia
C
Schmidt
Muriel T
MT
Davisson
Alberto C S
AC
Costa
D000818:Animals; D015350:Contrast Sensitivity / Q000502:physiology; D003433:Crosses, Genetic; D004195:Disease Models, Animal; D004314:Down Syndrome / Q000503:physiopathology*; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D012160:Retina / Q000503:physiopathology*; D012684:Sensory Thresholds; D013028:Space Perception / Q000502:physiology; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology