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. Author manuscript; available in PMC: 2017 Jan 1.
Published in final edited form as: Neurobiol Aging. 2015 Oct 29;37:117–126. doi: 10.1016/j.neurobiolaging.2015.09.019

Fig. 2.

Fig. 2

Age and sex differences in locus coeruleus (LC) signal intensity. (A) An example of a left and right LC in the neuromelanin-sensitive T1-weighted fast-spin echo images of one younger and one older adult. For illustrative purposes only, the intensity thresholds have been adjusted to maximize the visual contrast between the LC and adjacent brainstem tissue because the mean LC signal intensities differ significantly between age groups. Because each participant's fast spin-echo image is normalized relative to the noise in his/her image, such adjustments are only meant to demonstrate that the LC is clearly delineable in both age groups. (B) Age and sex differences in LC signal intensity are displayed as bars (means) for each subgroup. Bars reflect standard errors of the means. *p < 0.05.