Neurophysiological properties of cells filling the neonatal medial prefrontal cortex lesion cavity

Removal of the medial prefrontal cortex (mPFC) of the rat during the initial 7–12 days of life results in spontaneous filling of lesion cavity that is accompanied by recovery of cognitive and motor functions. To date, it remains uncertain whether tissue filling the lesion cavity is actually supporting the functional improvement. In the present study, we examined whether spontaneous neuronal activity could be recorded in adulthood from the tissue that fills the lesion cavity. We recorded EEG and multiunit activity in adulthood from the mPFC and the motor cortex of rats that had received neonatal mPFC lesions on post-natal day 10 (P10) or their non-lesioned littermate controls. We found similarities in both the firing pattern and firing rate of cells from the filled-in region compared to that of controls, although the power associated with peak frequencies in the delta, alpha, and beta range in the EEG recorded from the filled-in region was lower compared to controls. Overall, our results suggest that the cells found in the lesion cavity have similar neurophysiological properties to those found in normal tissue and thus should be capable of at least partially supporting the observed recovery of function.