Modulation of default-mode network activity by acute tryptophan depletion is associated with mood change: A resting state functional magnetic resonance imaging study

Department of Psychiatry and Neurosciences, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Neuroscience Research (Impact Factor: 2.15). 11/2010; 69(2):129-34. DOI: 10.1016/j.neures.2010.11.005
Source: PubMed

ABSTRACT Recently, resting-state fMRI (R-fMRI) has attracted interest based on its ability to detect the default mode network. We examined the effect of acute tryptophan depletion (ATD) on the fractional amplitude of low-frequency fluctuation (fALFF) during the resting state, and the correlation between changes of mood and fALFF following ATD. We manipulated the central serotonergic levels of 21 right-handed healthy males (mean age=21.57±1.83 years) following ATD. A within-subjects, double-blind, placebo-controlled, and counter-balanced design was employed. Following ATD or sham depletion, subjects completed the Profile of Mood States (POMS) and underwent 5-min R-fMRI scans. Our findings show that the fALFF of the middle orbitofrontal cortex and precuneus was significantly decreased and the fALFF of the superior parietal lobule, paracentral lobule and precentral gyrus was significantly increased after ATD. The fALFF of the orbitofrontal cortex was negatively correlated with depressive mood. The fALFF of the superior parietal lobule was positively correlated with anger-hostility and the fALFF of the paracentral lobule was negatively correlated with vigor-activity. The middle orbitofrontal cortex plays a key role in serotonin depletion-induced brain changes and individual differences in depressive mood change. These results serve to further elucidate the mechanism of ATD-induced relapse in remitted MDD patients.

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    • "in RS-fMRI studies [34] [35] [36] [37] [38] . Thus, we applied fALFF to investigate the low-frequency properties of brain activity during the RT-FFF and S-FFF states. "
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    • "In addition, serotonin transporter binding in the superior medial frontal cortex/BA 10 is altered in individuals with autism (Nakamura et al., 2010) and depression (Mann et al., 2000). Finally, following acute tryptophan depletion (a technique that lowers serotonin levels), resting-state activation in BA 10 decreases (Kunisato et al., 2011). These studies indicate that the superior medial frontal cortex/BA 10 is particularly sensitive to serotonin signaling and potentially to the 5-HTTLPR variant. "
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    • "Users could combine the two algorithms in their studies. REST-GCA is based on REST because REST provides a platform for fMRI data processing and has been used in many resting-state fMRI studies (e.g., Lui et al., 2009, 2010; Kunisato et al., 2011). REST-GCA supports both resting-state and task-state fMRI analysis in an individual subject mode or in a multi-subject batch mode. "
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