Poster No:
1883
Submission Type:
Abstract Submission
Authors:
Verónica Mäki-Marttunen1, Sander Nieuwenhuis2
Institutions:
1Oslo University Hospital, Oslo, NA, 2Leiden University, Leiden, Nord Holland
First Author:
Co-Author:
Introduction:
Brain activity fluctuates over time, and understanding the factors that influence such fluctuations is important to understand the flexible nature of brain and cognition. Recent electrophysiological and neuroimaging work in animals and humans has shown the presence of specific spatio-temporal patterns in global brain activity at infra-slow time scales. In particular, recent work showed that activity propagates from unimodal to transmodal areas, following a principal gradient that can be detected through different analytic approaches. Travelling waves have been proposed to explain the organization of brain activity into functional networks, but why there would be variation in the level of integration between networks is uncertain. Given the evidence that arousal-related neuromodulatory systems are known to affect network integration and that travelling waves activity are modulated by arousal state, we aimed to link these two lines of research and assess the hypothesis that neuromodulatory tone would be related to level of network integration by modulating the propagation of travelling waves.
Methods:
We tested our hypotheses using pharmacological fMRI concurrent with pupillometry in 36 healthy adults during rest and task performance. Participants underwent atomoxetine or placebo administration following a double-blind, counter-balanced design. Atomoxetine is known to increase extracellular catecholamine levels. Acquisitions were made in a 3T scanner and lasted approximately 60 minutes. fMRI data followed standard preprocessing and further filtering (0.01-0.08 Hz). Slow propagation of activity was detected around peaks of global signal as a delay profile following the spatial pattern of the principal gradient. Speed and ratio of travelling waves in different directions was calculated and compared using repeated measures ANOVA. Pupil size and level of network integration between functional connectivity networks were measured in intervals with travelling waves.
Results:
We found that the pharmacological manipulation was associated with faster travelling waves, and that faster travelling waves correlated with more network integration. We also examined temporal variations in pupil size, a signature of transient changes in neuromodulatory activity, and found that periods of travelling waves were characterized by larger pupil size.
Conclusions:
Our results suggest that neuromodulatory tone affects travelling wave propagation, and that this arousal-modulated propagation shapes integrated functional connectivity features, highlighting specific effects of prolonged and transient neuromodulatory influences on slow brain dynamics.
Novel Imaging Acquisition Methods:
BOLD fMRI 1
Physiology, Metabolism and Neurotransmission:
Pharmacology and Neurotransmission 2
Keywords:
Cognition
Cortex
FUNCTIONAL MRI
Noradrenaline
NORMAL HUMAN
Norpinephrine
Other - Pupillometry
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Resting state
Task-activation
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Healthy subjects
Was this research conducted in the United States?
No
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
NOTE: Any animal studies without IACUC approval will be automatically rejected.
Not applicable
Please indicate which methods were used in your research:
Functional MRI
Behavior
For human MRI, what field strength scanner do you use?
3.0T
Which processing packages did you use for your study?
Other, Please list
-
fmriprep
Provide references using APA citation style.
X et al.
No