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. Author manuscript; available in PMC: 2013 Nov 15.
Published in final edited form as: Neuroimage. 2012 Jul 20;63(3):1571–1584. doi: 10.1016/j.neuroimage.2012.07.015

Fig. 10.

Fig. 10

Amplitude and relative phase of measured [HbO] and [Hb] oscillation at the heart rate (HR: ~1 Hz) and respiratory rate (RR: ~0.3 Hz) at four source-detector separations of 1.0, 1.5, 2.0, and 2.5 cm. (a) [HbO]M, (b) [Hb]M and (c) φ[Hb] - φ[HbO] of measured oscillations at the heart rate as a function of sleep stages. (b) [HbO]M, (d) [Hb]M and (f) φ[Hb]-φ[HbO] of measured oscillations at the respiratory rate as a function of sleep stages. Different distance values are displayed with different symbols. The shortest (1 cm) and farthest (2.5 cm) source-detector separation distances were compared within each sleep stage by t and U2 tests (p < 0.05 indicated by *).