Epileptic baboons have lower numbers of neurons in specific areas of cortex

Significance We examined the variability of neuron packing densities across cortical regions and areas in two baboons with spontaneous, untreated epilepsy and two baboons without epilepsy. The two baboons without epilepsy had the distribution of neocortical neurons expected for Old World monkeys and baboons, whereas the baboons with untreated epilepsy had reduced numbers of cortical neurons overall, with the greatest reductions in motor and frontal areas of the cortex, and with little or no reduction in the primary visual cortex. The results suggest that neuron loss may follow untreated seizure activity, and this loss is greatest in areas of the cortex related to motor functions.