title: Modeling the effect of locus coeruleus firing on cortical state dynamics and single-trial sensory processing.
abstract: Neuronal responses to sensory stimuli are not only driven by feedforward sensory pathways but also depend upon intrinsic factors (collectively known as the network state) that include ongoing spontaneous activity and neuromodulation. To understand how these factors together regulate cortical dynamics, we recorded simultaneously spontaneous and somatosensory-evoked multiunit activity from primary somatosensory cortex and from the locus coeruleus (LC) (the neuromodulatory nucleus releasing norepinephrine) in urethane-anesthetized rats. We found that bursts of ipsilateral-LC firing preceded by few tens of milliseconds increases of cortical excitability, and that the 1- to 10-Hz rhythmicity of LC discharge appeared to increase the power of delta-band (1-4 Hz) cortical synchronization. To investigate quantitatively how LC firing might causally influence spontaneous and stimulus-driven cortical dynamics, we then constructed and fitted to these data a model describing the dynamical interaction of stimulus drive, ongoing synchronized cortical activity, and noradrenergic neuromodulation. The model proposes a coupling between LC and cortex that can amplify delta-range cortical fluctuations, and shows how suitably timed phasic LC bursts can lead to enhanced cortical responses to weaker stimuli and increased temporal precision of cortical stimulus-evoked responses. Thus, the temporal structure of noradrenergic modulation may selectively and dynamically enhance or attenuate cortical responses to stimuli. Finally, using the model prediction of single-trial cortical stimulus-evoked responses to discount single-trial state-dependent variability increased by ∼70% the sensory information extracted from cortical responses. This suggests that downstream circuits may extract information more effectively after estimating the state of the circuit transmitting the sensory message.
authors.affiliation: Neural Computation Laboratory, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy;
authors.forename: Houman
authors.identifier: http://orcid.org/0000-0002-8609-7397
authors.initials: H
authors.lastname: Safaai
authors.affiliation: Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany;
authors.forename: Ricardo
authors.initials: R
authors.lastname: Neves
authors.affiliation: Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany;
authors.forename: Oxana
authors.initials: O
authors.lastname: Eschenko
authors.affiliation: Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany; Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester M13 9PT, United Kingdom stefano.panzeri@iit.it nikos.logothetis@tuebingen.mpg.de.
authors.forename: Nikos K
authors.initials: NK
authors.lastname: Logothetis
authors.affiliation: Neural Computation Laboratory, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy; stefano.panzeri@iit.it nikos.logothetis@tuebingen.mpg.de.
authors.forename: Stefano
authors.initials: S
authors.lastname: Panzeri
mesh_terms: D000818:Animals; D005071:Evoked Potentials / Q000502:physiology*; D008125:Locus Coeruleus / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000502:physiology*
keywords: dynamical systems; information coding; oscillations; somatosensation; state dependence