Tracing amygdala habituation in highly anxious individuals

Meijer, Sjoerd

Tracing amygdala habituation in highly anxious individuals

Files

s4433890_Meijer,S_MSc_thesis_2020.pdf (1.41 MB)

Authors

Meijer, Sjoerd

Issue Date

2020-08-01

Language

en

URI

https://theses.ubn.ru.nl/handle/123456789/14670

Abstract

Inter-individual differences in amygdala habituation during emotional processing of salient stimuli are associated with anxiety levels in humans. Previous studies mainly focused on linear habituation dynamics, but more complex models may be more sensitive to the non-linear dynamics of the underlying neural mechanisms. The present functional MRI study used an emotional face matching task to trace amygdala habituation across blocks of stimulus repetitions. Participants (N = 219) were oversampled on elevated anxiety levels using the Hospital Anxiety and Depression Scale (HADS-A; score ≥ 8). We compared linear and non-linear amygdala habituation models using the mean absolute error as a measure of model fit. The results of our study reveal a cubic model to best fit the amygdala habituation pattern in a large sample of healthy but highly anxious individuals. We found no associations between inter-individual differences in features of the cubic habituation curve, i.e. beta-weights, and trait anxiety levels as measured by the HADS-A. Our study provides evidence of healthy variations in amygdala habituation that can be captured by non-linear models, but stronger alterations of habituation may be necessary to show an effect of single brain measures on anxiety levels. Future studies should consider the use of non-linear models to capture altered amygdala habituation dynamics in anxiety disorders, as these more complex models can capture a larger range of possible habituation phenotypes.