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Sci Rep. 2015 May 21;5:10499. doi: 10.1038/srep10499.

fMRI measurements of amygdala activation are confounded by stimulus correlated signal fluctuation in nearby veins draining distant brain regions.

Author information

1
1] Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria [2] MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.
2
Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria.
3
Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.
4
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
5
Department of Radiology, Tulln Hospital, Karl Landsteiner University of Health Sciences, Tulln, Austria.
6
1] Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria [2] MR Centre of Excellence, Medical University of Vienna, Vienna, Austria [3] Brain Behaviour Laboratory, Department of Psychiatry, University of Pennsylvania Medical Center, Philadelphia, PA, USA.

Abstract

Imaging the amygdala with functional MRI is confounded by multiple averse factors, notably signal dropouts due to magnetic inhomogeneity and low signal-to-noise ratio, making it difficult to obtain consistent activation patterns in this region. However, even when consistent signal changes are identified, they are likely to be due to nearby vessels, most notably the basal vein of rosenthal (BVR). Using an accelerated fMRI sequence with a high temporal resolution (TR = 333 ms) combined with susceptibility-weighted imaging, we show how signal changes in the amygdala region can be related to a venous origin. This finding is confirmed here in both a conventional fMRI dataset (TR = 2000 ms) as well as in information of meta-analyses, implying that "amygdala activations" reported in typical fMRI studies are likely confounded by signals originating in the BVR rather than in the amygdala itself, thus raising concerns about many conclusions on the functioning of the amygdala that rely on fMRI evidence alone.

PMID:
25994551
PMCID:
PMC4440210
DOI:
10.1038/srep10499
[Indexed for MEDLINE]
Free PMC Article

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