Multifocal visual evoked potentials in the anesthetized non-human primate.
OBJECTIVE
To evaluate monkey multifocal visual evoked cortical potentials (mfVEPs) recorded from central and peripheral fields for reliability and isolation from electroretinographic (ERG) activity.


METHODS
The mfVEP stimulus consisted of a 7-element hexagonal array that subtended 80 degrees of the central visual field. Recordings were made under intravenous pentobarbital sodium (15 mg/kg) anesthesia. Two monkeys with absent optic nerve and ganglion cell function after combined unilateral optic nerve transection and experimental ocular hypertension (ONT/OHT) were followed longitudinally. In a second study, 16 ophthalmologically normal monkeys were tested once.


RESULTS
Testing of the non-transected eye in two transected animals revealed robust first- and second-order kernel, first slice (K1 and K2.1) mfVEPs. Stimulation of the transected eye revealed no contamination of the mfVEP from the concurrently recorded multifocal ERGs. There was complete separation of the root-mean-square (RMS) mfVEP amplitudes from the transected and the fellow eyes tested repeatedly across a 4- to 17- month period. The largest amplitude mfVEP was generated by the central element; however, mfVEPs were recorded from outside the central 20 degrees element. The 16 normal animals showed waveforms similar to the normal eyes of the ONT/OHT animals both in shape and distribution throughout the visual field. A scalar-product measure showed both K1 and K2.1 mfVEPs from central and some peripheral elements were statistically distinct from noise.


CONCLUSIONS
mfVEPs can be reliably recorded from non-human primates anesthetized with pentobarbital. Under the recording conditions described, mfVEPs are not contaminated by ERG activity. mfVEPs may be useful in animal models of diseases that differentially affect macular and peripheral visual field responsiveness.
Maertz
Nathan A
NA
Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792-3220, USA.
Kim
Charlene B Y
CB
Nork
T Michael
TM
Levin
Leonard A
LA
Lucarelli
Mark J
MJ
Kaufman
Paul L
PL
Ver Hoeve
James N
JN
D000771:Anesthesia, Intravenous; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D008252:Macaca fascicularis; D008253:Macaca mulatta; D009900:Optic Nerve / Q000601:surgery; D010424:Pentobarbital / Q000008:administration & dosage; D015203:Reproducibility of Results; D012160:Retina / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*
D006993:Hypnotics and Sedatives; D010424:Pentobarbital