ELECTROPHYSIOLOGICAL PROPERTIES OF DORSAL LATERAL GENICULATE NEURONS IN BRAIN-SLICES FROM ME7 SCRAPIE-INFECTED MICE

Electrophysiological recordings using conventional intracellular techn iques were obtained from dorsal lateral geniculate nucleus (dLGN) neur ons in brain slices from ME7 scrapie-infected mice at specific time po ints throughout the incubation period of the disease. Comparisons were made with age-matched control mice. A number of dLGN neurons from con trol and scrapie-infected mice were injected with biocytin in order to examine their cellular morphology. Mice were infected with ME7 scrapi e by an intraocular route and the mean (+/- SEM) incubation period of the disease was 276 +/- 3.5 days. Our results indicate that there were no differences in the electrophysiological or morphological parameter s of neurons recorded in ME7 scrapie-infected and age-matched control mice at any stage of the disease up to 240 days postinoculation. After this time, however, no detectable electrical activity was recorded in the dLGN. This study demonstrates that in the ME7 scrapie-infected dL GN, relay neurons with normal physiological and morphological properti es are present even at an advanced stage of the disease at a time when the dLGN is known to be subject to marked pathological changes and a profound neuronal loss. (C) 1998 Academic Press.