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Relationship altered between functional T1ρ and BOLD signals in bipolar disorder
Journal article   Open access   Peer reviewed

Relationship altered between functional T1ρ and BOLD signals in bipolar disorder

Joseph J Shaffer, Casey P Johnson, Jeffrey D Long, Jess G Fiedorowicz, Gary E Christensen, John A Wemmie and Vincent A Magnotta
Brain and behavior, Vol.7(10), pp.e00802-n/a
10/2017
DOI: 10.1002/brb3.802
PMCID: PMC5651386
PMID: 29075562
url
https://doi.org/10.1002/brb3.802View
Published (Version of record) Open Access

Abstract

Introduction Functional neuroimaging typically relies on the blood‐oxygen‐level–dependent (BOLD) contrast, which is sensitive to the influx of oxygenated blood following neuronal activity. A new method, functional T1 relaxation in the rotating frame (fT1ρ) is thought to reflect changes in local brain metabolism, likely pH, and may more directly measure neuronal activity. These two methods were applied to study activation of the visual cortex in participants with bipolar disorder as compared to controls. Methods Thirty‐nine participants with bipolar disorder and 32 healthy controls underwent functional neuroimaging during a flashing checkerboard paradigm. Functional images were acquired in alternating blocks of BOLD and fT1ρ. Linear mixed‐effect models were used to examine the relationship between these two functional imaging modalities and to test whether that relationship was altered in bipolar disorder. Results BOLD and fT1ρ signal were strongly related in visual and cerebellar areas during the task in controls. The relationship between these two measures was reduced in bipolar disorder within the visual areas, cerebellum, striatum, and thalamus. Conclusions These results support a distinct mechanisms underlying BOLD and fT1ρ signals. The weakened relationship between these imaging modalities may provide a novel tool for measuring pathology in bipolar disorder and other psychiatric illnesses. Functional MR imaging was performed in participants with bipolar disorder using both blood‐oxygen‐level–dependent (BOLD) contrast and functional T1ρ during an identical flashing checkerboard task. We compared BOLD and functional T1ρ activity between groups. Our results showed that the relationship between BOLD and functional T1ρ was weakened in bipolar disorder in cerebellum, basal ganglia, and superior temporal lobe while the relationship was strengthened between these two imaging modalities in inferior temporal lobe, suggesting a decoupling between these two imaging modalities in bipolar disorder.
fMRI bipolar disorder BOLD T1ρ

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