Neuromodulatory control over nonlinear spiking of layer V pyramidal neurons mediates adaptive slightly subcritical network dynamics
Year: 2021
Type: preprint
Abstract: To remain adaptable to a dynamic environment, coordinated neural activity in the brain must be simultaneously flexible and reliable. There is evidence that the brain facilitates this adaptive response using highly-conserved metabotropic neuromodulatory neurotransmitters, such as noradrenaline and acetylcholine. While we understand how these neuromodulators alter individual neuronal dynamics, precisely how neuromodulation operates in networks of neurons to give rise to observed large-scale dynamics remains unknown. Here, we investigate this disparity by demonstrating correspondence between adaptive information processing modes - calculated on in vivo electrophysiological recordings of bursting layer V neurons in awake mice - and fluctuations in neuromodulatory tone - assessed by dynamic changes in pupil diameter. We theoretically validate these results by creating a novel, biologically plausible dual-compartment model of nonlinear layer V pyramidal neurons - capable of both regular spike and bursting modes - that reproduce our main empirical findings. We then demonstrate that the adrenergic and cholinergic neuromodulatory systems shift the brain into a neuroprotective (i.e., slightly subcritical) regime - assessed by the branching parameter - while facilitating flexible and reliable dynamics, respectively. This unexpected result demonstrates that the brain has circumvented the necessity to shift the system closer to criticality for variability by differentially augmenting an intrinsic neuronal nonlinearity. Our analyses establish that these distinct arms of the ascending arousal system modulate ensembles of layer V pyramidal neurons to augment critical dynamics and facilitate distinct adaptive information processing modes within the brain.
Source: arXiv (Cornell University)
Authors: Brandon R. Munn, Eli J. Müller, James M. Shine
Institution: The University of Sydney
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3166006491