NORADRENERGIC CONTRIBUTIONS TO LARGE-SCALE BRAIN NETWORK SHIFTS: A PRELIMINARY RESTING-STATE ANALYSIS
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2019-03-27
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en
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Abstract
Acute stress prompts noradrenergic activity that is theorized to drive functional brain network
shifts resulting in a prioritization of rapid vigilant behaviour over slower top-down functions.
Neurocognitive mechanisms underlying these behavioural changes are widely studied, however
the intrinsic alterations in noradrenergic system and its contribution to brain networks shifts
under acute stress is yet to be investigated in humans. Hence, the aim of the study was to
examine the resting-state alterations in the norepinephrine origin region, locus coeruleus (LC)
activity and stress-associated shifts in salience (SN), executive control (ECN) and default mode
networks (DMN). We expected a strong LC-SN connectivity during the immediate phase of
acute stress which was predicted to decrease over time (delayed phase) and vice versa for LCECN
and LC-DMN connectivity. An improvised method of LC preprocessing was performed
to obtain LC time courses which were linearly regressed with brain network time courses to
obtain beta coefficients. Since there were no significant results, we explored the network and
whole-brain LC connectivity analysis. LC showed differential connectivity patterns with SN,
ECN, DMN, parts of insular cortex and parahippocampal gyrus in acute stress conditions. These
results exhibit the inconsistency in the data but also partially align with the theory-based
expectations. Overall, due to the methodological and statistical concerns, the present study fails
to express a convincing support towards the theory of LC involvement in stress-related brain
network shifts, but with future investigation the explorative results could possess replicative
potential that might go in line with our hypotheses.
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Faculteit der Sociale Wetenschappen