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. Author manuscript; available in PMC: 2010 Jun 1.
Published in final edited form as: Sleep Med Clin. 2009 Jun;4(2):165–177. doi: 10.1016/j.jsmc.2009.01.004

Figure 2.

Figure 2

Phase shifts (panel A) and melatonin suppression (Panel B) in response to a 3-cycle 5-hour light stimulus in young adults. The magnitude of the phase shift (in hours) is plotted with respect to the illuminance of the light stimulus (in lux). Symbols represent mean (± s.e.m.) responses from each group of 7–9 subjects. The solid line represents a 3-paramater logistic curve fit to the data, and the upper and lower 95% confidence intervals of this fit are shown in the dashed lines. Figure reproduced with permission from Reference 63 [Zeitzer JM, Khalsa SB, Boivin DB, Duffy JF, Shanahan TL, Kronauer RE, and Czeisler CA. Temporal dynamics of late-night photic stimulation of the human circadian timing system. Am J Physiol 2005; 289(3):R839–R844].