Table 1.

Patient characteristics. Age at onset indicates the age at which seizures are first described by the patient. For each subject, N seizures were analyzed with durations listed in the fifth column. “Grids” and “strips” refer to surface (pial) electrode arrays which were also always accompanied by depth electrodes. “Depths” refer to patients who only received orthogonal placement of intraparenchymal arrays of electrodes. The total number of intracranial electrodes and the number of electrodes involved at seizure onset are listed for the dominant seizure type. All seizure types were either complex partial seizures which had secondary generalization (CPS+2nd), complex partial seizures without secondary generalization (CPS), or simple partial seizures (SPS); the number of each type of seizure for each patient is indicated. The frequency bands of maximum power at seizure onset were estimated using standard power spectrum analysis. Power spectra (Hann taper) were computed for 1s of ECoG data immediately following clinical determination of seizure initiation and averaged over the onset electrodes. Beta=15–30 Hz, Alpha=8–12 Hz, Theta=4–8 Hz, Delta=1–4 Hz. The etiology based on history, imaging and seizure semiology refers to a diagnosis made by the clinical team with all available data prior to implantation of electrodes, surgical resection and pathological examination of resected tissue. The etiology based on pathology comes directly from the clinical determination made by neuropathologists. The lobe of involvement was determined by examination of the seizure onsets on the intracranial recording electrodes. MTS = mesial temporal sclerosis. Etiology notes: 1) Bilateral onsets – no resection performed, 2) Eloquent cortex – no resection performed, 3) Patient decided not to go forward with resection.

Patient	Sex	Age at Onset / Surgery	N	Duration of seizures (s)	Electrodes	Electrodes total / onset	Seizure type (Number)	Onset activity	Etiology	Etiology (based on pathology)	Lobe of involvement
A	M	3 / 37	4	76, 63, 61,134	Grids, strips and depths	100 / 5	CPS+2nd (4)	Beta, Alpha, Delta	Unknown	No significant abnormalities	Temporal (lateral)
B	F	20 / 45	4	114, 102, 121, 142	Depths	65 / 5	CPS+2nd (4)	Delta	Temporal lobe - MTS	No pathology obtained ¹	Temporal (mesial)
C	F	15 / 46	5	87, 93, 102, 100, 112	Grids, strips and depths	122 / 5	CPS+2nd (5)	Beta, Alpha, Delta	Cortical Dysplasia	Cortical Dysplasia	Temporo- parieto- occipital
D	F	17 / 45	3	80, 82, 42	Depths	40 / 2	CPS+2nd, CPS (2,1)	Beta, Delta	Possible post- infectious	No pathology obtained ²	Parieto- Occipital
E	M	7 / 22	2	87, 92	Grids, strips and depths	124 / 4	CPS+2nd (2)	Delta	Cortical Dysplasia	Cortical Dysplasia	Frontal (cingulate)
F	F	14 / 28	4	331, 111, 84, 128	Grids, strips and depths	94 / 22	CPS+2nd, CPS, SPS (1,1,2)	Delta	Encephalitis	Reactive gliosis	Temporal (mesial)
G	M	17 / 29	7	93, 137, 104, 134, 156, 179, 101	Depths	70 / 2	CPS, SPS (5,2)	Delta	Traumatic Brain Injury	Reactive gliosis	Temporal (mesial)
H	F	13 / 31	2	65, 90	Depths	34 / 4	CPS (2)	Delta	Temporal lobe - MTS	No significant abnormalities	Temporal (mesial)
I	M	43 / 45	8	55, 57, 63, 49, 58, 199, 54, 90	Depths	64 / 4	CPS+2nd, CPS, SPS (1,1,6)	Alpha, Delta	Unknown	No pathology obtained ¹	Temporal (mesial and lateral)
J	M	14 / 19	4	82, 138, 123, 40	Grids, strips and depths	80 / 3	SPS (4)	Alpha, Delta	Temporal lobe - MTS	Hippocampal sclerosis	Temporo- parieto- occipital
K	F	59 / 65	5	171, 121, 105, 224, 133	Depths	68 / 2	CPS, SPS (4,1)	Beta, Alpha	Unknown	No pathology obtained ³	Frontal (orbito-frontal)