Poster No:
1396
Submission Type:
Abstract Submission
Authors:
Christopher Whyte1, Gabriel Wainstein1, Eli Muller1, Brandon Munn1, James Shine1
Institutions:
1University of Sydney, Camperdown, NSW
First Author:
Co-Author(s):
Introduction:
Perceptual updating has been hypothesized to rely on a network reset event modulated by bursts of ascending neuromodulatory neurotransmitters, such as noradrenaline, abruptly altering the brain's susceptibility to changing sensory activity (Bouret & Sara, 2005; Sales et al., 2019). To test this hypothesis at a large-scale, we analysed an ambiguous figures task using pupillometry, functional magnetic resonance imaging (fMRI), and neurobiologically constrained recurrent neural network modelling.
Methods:
To assess the role of the ascending arousal activity during task performance, we analysed a dataset of 35 participants who performed an ambiguous figures (Fig 1A) task whilst simultaneously recording pupil diameter (a non-invasive readout of phasic noradrenergic tone Fig 1B-D; Einhäuser et al., 2008). To explore this hypothesis computationally, we trained a neurobiologically constrained recurrent neural network (RNN) on an analogous perceptual categorisation task, allowing gain to change dynamically with classification uncertainty (Fig 1E-F). We then leveraged a novel statistical physics (Munn et al., 2021) based measure of the energy landscape traversed by the RNN dynamics to derive a set of predictions that could then be tested in fMRI data recorded whilst participants performed the same task (Fig 2A-F).
Results:
Behaviourally, qualitative shifts in the perceptual interpretation of an ambiguous image were associated with peaks in pupil diameter, an indirect readout of phasic bursts in neuromodulatory tone (Fig 1C-D). In the RNN, higher gain (our model-based construct representing neuromodulatory tone) accelerated perceptual switching by transiently destabilizing the network's dynamical regime in periods of maximal uncertainty (Fig 1E-F). We leveraged a low-dimensional readout of the RNN dynamics, to develop two novel macroscale predictions: perceptual switches should occur with peaks in low-dimensional brain state velocity (Fig 2B) and with flattened energy landscape (Fig 2C-D) akin to the transient application of an external "force" injecting kinetic energy into the system. Using fMRI we confirmed these predictions (Fig 2E-G), highlighting the role of the neuromodulatory system in the large-scale network reconfigurations mediating adaptive perceptual updates.
Conclusions:
We provide computational and empirical evidence for the association between neuromodulation, pupil dilation, and energy landscape flattening in task-relevant perceptual switches. Our results strengthen our understanding of the neurobiological processes underpinning moment-by-moment adaptive changes to perception and suggest that the widespread excitatory projections of the ascending arousal system may mediate the systems-level reconfigurations of cortical network architecture via uncertainty driven alterations in neural gain.
Modeling and Analysis Methods:
fMRI Connectivity and Network Modeling 1
Perception, Attention and Motor Behavior:
Perception: Visual
Physiology, Metabolism and Neurotransmission:
Pharmacology and Neurotransmission 2
Keywords:
Computational Neuroscience
Noradrenaline
Perception
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.
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?
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Not applicable
Please indicate which methods were used in your research:
Functional MRI
Computational modeling
For human MRI, what field strength scanner do you use?
1.5T
Which processing packages did you use for your study?
SPM
Free Surfer
Provide references using APA citation style.
Bouret, S., & Sara, S. J. (2005). Network reset: A simplified overarching theory of locus coeruleus noradrenaline function. Trends in Neurosciences, 28(11), 574–582. https://doi.org/10.1016/j.tins.2005.09.002
Einhäuser, W., Stout, J., Koch, C., & Carter, O. (2008). Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry. Proceedings of the National Academy of Sciences, 105(5), 1704–1709. https://doi.org/10.1073/pnas.0707727105
Munn, B. R., Müller, E. J., Wainstein, G., & Shine, J. M. (2021). The ascending arousal system shapes neural dynamics to mediate awareness of cognitive states. Nature Communications, 12(1), 6016. https://doi.org/10.1038/s41467-021-26268-x
Sales, A. C., Friston, K. J., Jones, M. W., Pickering, A. E., & Moran, R. J. (2019). Locus Coeruleus tracking of prediction errors optimises cognitive flexibility: An Active Inference model. PLOS Computational Biology, 15(1), e1006267. https://doi.org/10.1371/journal.pcbi.1006267
No