Deviation of somatosensory evoked potential and lateral dominance of spike activity in iron-induced epileptic cortex of the rat.

A chronic epileptic focus was induced by a microinjection of ferric chloride solution into the sensorimotor cortex of rats. Two types of somatosensory evoked potentials (SEPs) were recorded from the cortex near the injection site. In animals showing an initial positive-negative biphasic SEP, spikes appeared in electrocorticograms (ECoGs) more frequently on the side ipsilateral to the injection site than on the contralateral side, whereas in animals showing an initial negative monophasic SEP, spikes appeared more frequently on the contralateral side.