Electroencephalogram (EEG) pattern represents the electric activity of brain cells. Its recordings have helped clinicians for decades to diagnose specific diseases of the central nervous system. The present study characterized behaviors and EEG patterns after injection with kainic acid (KA) in rats. Male Wistar rats (300-350g, n=6) were anesthetized with 60 mg/kg Zoletil® 100 (i.m.). Assessment of depth anesthetic was evaluated by gentle toe pinch withdrawal reflex. During the surgery, the depth of anesthetic was also evaluated periodically and additional anesthetic was injected to animal that was found with any reaction of too light anesthesia. Then rats were implanted stainless steel screw electrodes on both sides of the parietal cortices (AP; -4, ML; 4) for EEG recording and a cannula for KA injection into right dorsal hippocampus (AP; -4.2, ML; 3.6, DV; 3.8). Rats were sacrificed by thiopental sodium overdose injection. Results showed that the injection of KA (1 nmol/µl) 1 µl into hippocampus (continuously 7 days) induced hyperactivity of hippocampal neurons via kainate receptor. KA administration did not induce neither increase in explorative behavior nor change in learning and memory behavior, observed in Y-maze test (5min.). EEG signals of individual rats were recorded for 2-h period through connection of recording cables. EEG signals were digitized at 400 Hz by a PowerLab/4SP system (AD Instruments) with 12-bit A/D, and stored in a PC through the Chart program software. The EEG signals were processed through 1.25 – 45 Hz band pass filter. The digitized EEG data were segmented into 1024-point (50% overlap) and the signals were converted to power spectra by the fast Fourier transform algorithm (Hanning window cosine transform). Intrahippocampal injection of KA induced paroxysmal discharges in the ipsilateral EEG. This abnormality of brain wave of frequent spikes occurred either in isolated or short bursts. Saline injection did not induce any change in EEG patterns. EEG spectral power analysis revealed the ipsilateral increase in power density (µV2/Hz) of slow wave activity (0.125-5 Hz, 18.55%) and decrease in power density of fast wave activity (23-45 Hz, 6.97%) compared to pretreatment levels (p<0.05,compared by T-test). The 7th day after injection (last day) rats with KA administration showed only the decrease in theta activity (4-7 Hz, 5.32%). No similar finding was observed contralaterally. This study demonstrated cortical EEG characteristics following activation of hippocampal neurons via glutamate receptor. The data suggest that EEG study is sufficiently accurate to identify brain site and time dependent effects of neurodegenerative induction.