Chapter 42 Functional consequences of neocortical transplants in rats with a congenital brain defect: electrophysiology and behavior

Abstract

Publisher Summary This chapter discusses approach for discovering conditions under which normal fetal tissue transplanted into infant brains could ameliorate impaired function resulting from congenital brain defects. The approach is unique in 2 respects: (1) by adding new rather than replacing lost tissue, it improves the function of the host brain beyond its intrinsic capacity and (2) functional effects are assessed at maturity and in old age, even though transplants are sustained in infancy. The effect of transplants on some of the impaired behaviors is described in the chapter. In the approach described in the chapter, although the transplant was structurally well integrated into the host brain, its presence reduced neither the hyperactivity of micrencephalic rats in an open field nor the deficit they display in learning a multiple choice water maze. Both tests were done at 2 months and one year after transplantation. Electrophysiological recordings of electroencephalography and visual evoked potentials (VEP) obtained from young adult transplant-bearing micrencephalic rats have been more encouraging. Salutary transplant effects were also observed with two different behavioral tests given at older ages, a visual pattern discrimination test and spatial navigation.