Table 1.

Sleep potential recorded from subcortical structures in humans.

Study	Patients	Electrode Placement	Monopolar or bipolar	Subcortical sleep rhythm	Notes
Urrestarazu et al. (2009) [47]	N = 10, PD	STN	Bipolar subcortical, EEG common average	K-complex, Spindles	Some spindles occurred simultaneously in Cz. Subcortical spindles not recorded in all patients. Half of patients recorded during daytime naps rather than nocturnal sleep
Velasco et al. (2002) [67]	N = 5, Lennox-Gastaut Syndrome	CM	Monopolar (ipsilateral earlobes)	K-complex, Vertex waves, Spindles	Vertex waves occurred in scalp first, spindles occurred in thalamus first
Moiseeva et al. (1969) [61]	N = 11, diagnosis not specified	Globus pallidus, putamen, hypothalamus, ventrolateral & posterior thalamic nucleus, hypothalamus, STN, substantia nigra)	Not documented	Spindles	Abstract only
Salih et al. (2009) [56]	N = 7, dystonia	GPi	Bipolar	K-complexes Spindles	Subcortical potentials occurred in association with scalp.
Tsai et al. (2010) [68]	N = 3, epilepsy	Anterior nucleus	Bipolar	Spindles	Spindles occurred at the same time in anterior nucleus and scalp. K complexes only seen on scalp potentials.
Wennberg & Lozano (2003) [65]	N = 7, epilepsy, PD	Centromedian nucleus, anterior nucleus, STN	Monopolar to Cz, Pz or sphenoidal electrode	K-complex Vertex waves Spindles	Sleep potentials occurred simultaneously and in opposite polarities

Abbreviations: CM (centromedian nucleus), GPi (globus pallidus internus), PD (Parkinson's disease), STN (subthalamic nucleus).