Axotomized and intact neurons of injured cortex are differentially altered. (A) Mean frequency of miniature excitatory postsynaptic currents (mEPSCs) was increased at 1 d, but returned to control levels at 2 d after injury in axotomized cells. In contrast, intact neurons showed a significant increase only at 2 d post injury. (analysis of variance [ANOVA]; *=p<0.05). (B) Mean amplitude of mEPSCs was not affected. (C) Cumulative probability of interevent interval shows that most events occur at longer intervals in 1 d intact neurons relative to control cells, but at shorter intervals than controls in all three other groups. (D) Ratio of mEPSC frequency to spontaneous EPSC (sEPSC) frequency. In control cells ∼80% of events come from miniature events. This ratio is not significantly different for 1 d axotomized and 2 d intact neurons, but is significantly lower for 2 d axotomized and 1 d intact cells (ANOVA; *=p<0.05). n=15 control, five 1 d axotomized, 10 two day axotomized, five 1 d intact, and four 2 d intact layer V yellow fluorescent protein (YFP)+pyramidal neurons.