%0 Journal Article %T Effects of visual deprivation on epileptic activity in mature rat visual cortex %J Physiology and Pharmacology %V 3 %N 1 %U http://ppj.phypha.ir/article-1-348-en.html %R %D 1999 %K Brain Slice; Neocortex; Epileptic field potential; Dark-rearing; Picrotoxin, %X   Effects of visual deprivation on the induction of epileptiform activity were studied in layer II/III of mature rat primary visual cortex. Field potentials were evoked by stimulation of layer IV in slices from control and dark-reared (OR) rats. Picrotoxin (PTX)-induced epileptic activity was characterized by spontaneous and evoked epileptic field potentials (EFPs). The results showed that OR slices demonstrate greater susceptibility for induction of spontaneous EFP. PTX-induced changes in the properties of evoked field potentials also showed higher tendency of OR animals to epileptogenesis. In both groups, field potentials are consisted of pEPSP1 (population excitatory post-synaptic potential 1, i.e. first negativity) and pEPSP2 (second negativity). PTX significantly increased the amplitude and duration of pEPSP2, but it had no significant effect on pEPSP1. PTX-induced changes in characteristics of pEPSP2 were significantly higher in OR slices. It is concluded that visual deprivation causes lasting changes in layer II/III of visual cortex that retain in slices and predispose this area for PTX-induced epileptiform activity. %> http://ppj.phypha.ir/article-1-348-en. %P 59-65 %& 59 %! %9 Experimental research article %L A-10-110-88 %+ %G eng %@ 24765236 %[ 1999