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Hum Brain Mapp. 2017 Sep;38(9):4313-4321. doi: 10.1002/hbm.23616. Epub 2017 Jun 5.

Heightened amygdala responsiveness in s-carriers of 5-HTTLPR genetic polymorphism reflects enhanced cortical rather than subcortical inputs: An MEG study.

Author information

1
Unit on Affective Cognitive Neuroscience, NIMH/NIMH, Bethesda, MD, USA.
2
MEG Core Facility, NIMH/NIH, Bethesda, MD, USA.
3
Departments of Psychiatry and Anatomy & Cell Biology, Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada.
4
Bioinformatics and Computational Biosciences Branch, NIAID/NIH, Rockville, MD, USA.
5
Laboratory of Neurogenetics, NIAAA/NIH, Bethesda, MD, USA.
6
Scientific and Statistical Computing Core, NIMH/NIH, Bethesda, MD, USA.

Abstract

Short allele carriers (S-carriers) of the serotonin transporter gene (5-HTTLPR) show an elevated amygdala response to emotional stimuli relative to long allele carriers (LL-homozygous). However, whether this reflects increased responsiveness of the amygdala generally or interactions between the amygdala and the specific input systems remains unknown. It is argued that the amygdala receives input via a quick subcortical and a slower cortical pathway. If the elevated amygdala response in S-carriers reflects generally increased amygdala responding, then group differences in amygdala should be seen across the amygdala response time course. However, if the difference is a secondary consequence of enhanced amygdala-cortical interactions, then group differences might only be present later in the amygdala response. Using magnetoencephalography (MEG), we found an enhanced amygdala response to fearful expressions starting 40-50 ms poststimulus. However, group differences in the amygdala were only seen 190-200 ms poststimulus, preceded by increased superior temporal sulcus (STS) responses in S-carriers from 130 to 140 ms poststimulus. An enhanced amygdala response to angry expressions started 260-270 ms poststimulus with group differences in the amygdala starting at 160-170 ms poststimulus onset, preceded by increased STS responses in S-carriers from 150 to 160 ms poststimulus. These suggest that enhanced amygdala responses in S-carriers might reflect enhanced STS-amygdala connectivity in S-carriers. Hum Brain Mapp 38:4313-4321, 2017.

KEYWORDS:

5-HTTLPR; amygdala; emotion; magnetoencephalography; serotonin transporter

PMID:
28580622
PMCID:
PMC5578743
DOI:
10.1002/hbm.23616
[Indexed for MEDLINE]
Free PMC Article

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