Table 1.

Spindle occurrence across multiple regions in the human brain

Region	Number of channels with spindle detections		Density (spindles/min)
Scalp
Fz	12/13	(92%)	1.8	(±0.30)
C3–C4	22/26	(85%)	1.9	(±0.22)
Pz	12/12	(100%)	1.8	(±0.30)
	46/51	(90%)	1.9	(±0.13)
Frontal lobe
Supplementary motor area	3/3	(100%)	1.2	(±0.49)
Orbitofrontal cortex	14/15	(93%)	2.2	(±0.24)
Anterior cingulate	14/16	(88%)	1.6	(±0.25)
Presupplementary motor area	4/7	(57%)	1.5	(±0.90)
Lateral frontal	2/4	(50%)	1.8	(±0.86)
	37/45	(82%)	1.8	(±0.16)
Parietal lobe
Posterior cingulate	7/8	(88%)	1.1	(±0.29)
Posterior parietal	1/1	(100%)	2.2	(NA)
	8/9	(89%)	1.3	(±0.29)
Temporal lobe
Temporal gyrus	4/6	(80%)	2.1	(±0.28)
Parahippocampal gyrus	11/16	(69%)	1.3	(±0.25)
Hippocampus	9/23	(44%)	1.1	(±0.13)
Entorhinal cortex	4/13	(31%)	0.74	(±0.11)
Amygdala	4/19	(21%)	0.89	(±0.18)
	32/79	(41%)	1.2	(±0.12)

Columns (left to right) show the brain region, the number of channels with spindle detections (over the total number of electrodes in that region), and the mean density of spindles per minute (±SEM across electrodes, n = 13 individuals). Note that while frontal and parietal regions showed robust spindle activity (comparable to scalp EEG channels), there was large variability in the occurrence and density of spindles in the medial temporal lobe.