TABLE 1.

Comparison of EEG spikes and waves during neocortical electrographic seizures

EEG spike (PDS)	EEG wave
Depolarizing phase	Hyperpolarizing phase
EEG (field potential) negativity	EEG (field potential) positivity
All neocortical cell types fire	No neocortical cell type fires
Conductance increases	Conductance decreases; disfacilitation
Chloride-dependent IPSPs are present	Not GABA mediated
Mediated by EPSPs (NMDA and non-NMDA); persistent sodium current controls PDS amplitude	Calcium-dependent potassium current controls PDS amplitude and duration (not affected by chloride injection from KCl-filled pipettes)

EEG, electroencephalogram; PDS, paroxysmal depolarization shift; EPSP, excitatory postsynaptic potential; IPSP, inhibitory postsynaptic potential; NMDA, N-methyl-d-aspartate; GABA, γ-aminobutyric acid; KCl, potassium chloride.