Lateralization of amygdala activation in fMRI may depend on phase-encoding polarity.
Summary of "Lateralization of amygdala activation in fMRI may depend on phase-encoding polarity."
OBJECT:
Susceptibility artifacts along the phase-encoding (PE) direction impact the activation pattern in the amygdala and may lead to systematic asymmetries. We implemented a triple-echo echo-planar imaging (EPI) sequence, acquiring opposite PE polarities along left-right PE direction in a single shot, to investigate its effects on amygdala lateralization. MATERIALS AND
METHODS:
Twelve subjects viewed emotional faces to evoke amygdala activation. RESULTS AND
CONCLUSION:
A region of interest analysis revealed that the lateralization of amygdala responses depended on the PE polarity thus representing a pure method artifact. Alternating PE with multi-echo EPI reduced the artifact. Lateralized fMRI activation in areas with magnetic field inhomogeneities need to be interpreted with caution.
Affiliation
Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Neuenhofer Weg 21, 52074, Aachen, Germany, kamathiak@ukaachen.de.
Journal Details
This article was published in the following journal.
Name: Magma (New York, N.Y.)
ISSN: 0968-5243
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22009130
- DOI: http://dx.doi.org/10.1007/s10334-011-0285-4
Medical and Biotech [MESH] Definitions
Amygdala
Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system.
Interphase
The interval between two successive CELL DIVISIONS during which the CHROMOSOMES are not individually distinguishable. It is composed of the G phases (G1 PHASE; G0 PHASE; G2 PHASE) and S PHASE (when DNA replication occurs).
Metabolic Detoxication, Phase I
Functionalization of exogenous substances to prepare them for conjugation in PHASE II DETOXIFICATION. Phase I enzymes include CYTOCHROME P450 enzymes and some OXIDOREDUCTASES. Excess induction of phase I over phase II detoxification leads to higher levels of FREE RADICALS that can induce CANCER and other cell damage. Induction or antagonism of phase I detoxication is the basis of a number of DRUG INTERACTIONS.
G2 Phase
The period of the CELL CYCLE following DNA synthesis (S PHASE) and preceding M PHASE (cell division phase). The CHROMOSOMES are tetraploid in this point.
Cell Cycle
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
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