Focal lesions were placed in the visual cortex of Long-Evans hooded rats, immediately below skull screw recording electrodes. Lesions were produced by heat and extended an average depth of about 0.9 mm below the cortical surface. Evoked potentials recorded from the electrode overlying the cortical lesion were compared to simultaneously recorded potentials from a contralateral homotopic site. The effects of the lesions were selective. Flash evoked potential (FEP) peaks P1, P2, and N2 were depressed by the lesion, while peaks N1 and P3 were augmented. Peak N3 was depressed by the lesion, while peaks N1 and P2 were made more distinct. The results emphasized that different peaks have different generators, and suggest in particular that FEP peaks P1 and N2, and peak N3 of the pattern reversal evoked potential require the superficial layers of the cortex.