In order to search for possible evidence of active compensation during recovery from brain damage, EEG and evoked potential recordings were taken from cats prepared with chronically implanted electrodes in sensorimotor cortex, suprasylvian gyrus, and other cortical and deep areas, before and after various sensorimotor cortical lesions. The animals were tested concurrently on a battery of neurological tests. As in an earlier study limited to SI alone, lesions of SI or of SII, or larger ablations involving adjacent tissue, were followed by degenerative changes in potentials evoked by forelimb stimulation and then by partial recovery in some cases. Similarly, only degenerative changes were seen in responsiveness to brain stimulation, tested in some animals. Compensatory hyperresponsiveness was not seen. EEG results were consistent with the clinical literature in showing reduction in amplitudes, particularly of fast activity, sometimes accompanied by increased slow activity, greatest near the site of damage. Though SII might be thought of as partly redundant with SI, and therefore important in recovery, SII was not particularly responsive to damage to SI. Additional, suggestive changes following cortical damage were seen in some cases, e.g., 25–40 Hz spindles in orbital cortex, but these need further corroboration. Although more subtle measures might reveal additional positive findings, outside the range of spontenaous variability in the EEG, future investigations should also consider whether EEG slowing plays an active role in recovery or whether it is epiphenomenal.