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Bhattacharya S, Cauchois MBL, Iglesias PA, Chen ZS. The impact of a closed-loop thalamocortical model on the spatiotemporal dynamics of cortical and thalamic traveling waves. Sci Rep 2021; 11:14359. [PMID: 34257333 PMCID: PMC8277909 DOI: 10.1038/s41598-021-93618-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 06/21/2021] [Indexed: 12/23/2022] Open
Abstract
Propagation of activity in spatially structured neuronal networks has been observed in awake, anesthetized, and sleeping brains. How these wave patterns emerge and organize across brain structures, and how network connectivity affects spatiotemporal neural activity remains unclear. Here, we develop a computational model of a two-dimensional thalamocortical network, which gives rise to emergent traveling waves similar to those observed experimentally. We illustrate how spontaneous and evoked oscillatory activity in space and time emerge using a closed-loop thalamocortical architecture, sustaining smooth waves in the cortex and staggered waves in the thalamus. We further show that intracortical and thalamocortical network connectivity, cortical excitation/inhibition balance, and thalamocortical or corticothalamic delay can independently or jointly change the spatiotemporal patterns (radial, planar and rotating waves) and characteristics (speed, direction, and frequency) of cortical and thalamic traveling waves. Computer simulations predict that increased thalamic inhibition induces slower cortical frequencies and that enhanced cortical excitation increases traveling wave speed and frequency. Overall, our results provide insight into the genesis and sustainability of thalamocortical spatiotemporal patterns, showing how simple synaptic alterations cause varied spontaneous and evoked wave patterns. Our model and simulations highlight the need for spatially spread neural recordings to uncover critical circuit mechanisms for brain functions.
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Affiliation(s)
- Sayak Bhattacharya
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Matthieu B L Cauchois
- Department of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Pablo A Iglesias
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
| | - Zhe Sage Chen
- Department of Psychiatry, Department of Neuroscience and Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, 10016, USA.
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Oprea L, Pack CC, Khadra A. Machine classification of spatiotemporal patterns: automated parameter search in a rebounding spiking network. Cogn Neurodyn 2020; 14:267-280. [PMID: 32399070 PMCID: PMC7203379 DOI: 10.1007/s11571-020-09568-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 11/20/2019] [Accepted: 01/03/2020] [Indexed: 12/20/2022] Open
Abstract
Various patterns of electrical activities, including travelling waves, have been observed in cortical experimental data from animal models as well as humans. By applying machine learning techniques, we investigate the spatiotemporal patterns, found in a spiking neuronal network with inhibition-induced firing (rebounding). Our cortical sheet model produces a wide variety of network activities including synchrony, target waves, and travelling wavelets. Pattern formation is controlled by modifying a Gaussian derivative coupling kernel through varying the level of inhibition, coupling strength, and kernel geometry. We have designed a computationally efficient machine classifier, based on statistical, textural, and temporal features, to identify the parameter regimes associated with different spatiotemporal patterns. Our results reveal that switching between synchrony and travelling waves can occur transiently and spontaneously without a stimulus, in a noise-dependent fashion, or in the presence of stimulus when the coupling strength and level of inhibition are at moderate values. They also demonstrate that when a target wave is formed, its wave speed is most sensitive to perturbations in the coupling strength between model neurons. This study provides an automated method to characterize activities produced by a novel spiking network that phenomenologically models large scale dynamics in the cortex.
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Affiliation(s)
- Lawrence Oprea
- Department of Physiology, McGill University, Montréal, QC Canada
| | - Christopher C. Pack
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC Canada
| | - Anmar Khadra
- Department of Physiology, McGill University, Montréal, QC Canada
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Naro A, Portaro S, Milardi D, Billeri L, Leo A, Militi D, Bramanti P, Calabrò RS. Paving the way for a better understanding of the pathophysiology of gait impairment in myotonic dystrophy: a pilot study focusing on muscle networks. J Neuroeng Rehabil 2019; 16:116. [PMID: 31533780 PMCID: PMC6751609 DOI: 10.1186/s12984-019-0590-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/09/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND A proper rehabilitation program targeting gait is mandatory to maintain the quality of life of patients with Myotonic dystrophy type 1 (DM1). Assuming that gait and balance impairment simply depend on the degree of muscle weakness is potentially misleading. In fact, the involvement of the Central Nervous System (CNS) in DM1 pathophysiology calls into account the deterioration of muscle coordination in gait impairment. Our study aimed at demonstrating the presence and role of muscle connectivity deterioration in patients with DM1 by a CNS perspective by investigating signal synergies using a time-frequency spectral coherence and multivariate analyses on lower limb muscles while walking upright. Further, we sought at determining whether muscle networks were abnormal secondarily to the muscle impairment or primarily to CNS damage (as DM1 is a multi-system disorder also involving the CNS). In other words, muscle network deterioration may depend on a weakening in signal synergies (that express the neural drive to muscles deduced from surface electromyography data). METHODS Such an innovative approach to estimate muscle networks and signal synergies was carried out in seven patients with DM1 and ten healthy controls (HC). RESULTS Patients with DM1 showed a commingling of low and high frequencies among muscle at both within- and between-limbs level, a weak direct neural coupling concerning inter-limb coordination, a modest network segregation, high integrative network properties, and an impoverishment in the available signal synergies, as compared to HCs. These network abnormalities were independent from muscle weakness and myotonia. CONCLUSIONS Our results suggest that gait impairment in patients with DM1 depends also on a muscle network deterioration that is secondary to signal synergy deterioration (related to CNS impairment). This suggests that muscle network deterioration may be a primary trait of DM1 rather than a maladaptive mechanism to muscle degeneration. This information may be useful concerning the implementation of proper rehabilitative strategies in patients with DM1. It will be indeed necessary not only addressing muscle weakness but also gait-related muscle connectivity to improve functional ambulation in such patients.
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Affiliation(s)
- Antonino Naro
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | - Simona Portaro
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | - Demetrio Milardi
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | - Luana Billeri
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | - Antonino Leo
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | | | - Placido Bramanti
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
| | - Rocco Salvatore Calabrò
- IRCCS Centro Neurolesi Bonino Pulejo, via Palermo, SS 113, Ctr. Casazza, 98124 Messina, Italy
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Soman K, Muralidharan V, Chakravarthy VS. An Oscillatory Neural Autoencoder Based on Frequency Modulation and Multiplexing. Front Comput Neurosci 2018; 12:52. [PMID: 30042669 PMCID: PMC6048285 DOI: 10.3389/fncom.2018.00052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/19/2018] [Indexed: 11/13/2022] Open
Abstract
Oscillatory phenomena are ubiquitous in the brain. Although there are oscillator-based models of brain dynamics, their universal computational properties have not been explored much unlike in the case of rate-coded and spiking neuron network models. Use of oscillator-based models is often limited to special phenomena like locomotor rhythms and oscillatory attractor-based memories. If neuronal ensembles are taken to be the basic functional units of brain dynamics, it is desirable to develop oscillator-based models that can explain a wide variety of neural phenomena. Autoencoders are a special type of feed forward networks that have been used for construction of large-scale deep networks. Although autoencoders based on rate-coded and spiking neuron networks have been proposed, there are no autoencoders based on oscillators. We propose here an oscillatory neural network model that performs the function of an autoencoder. The model is a hybrid of rate-coded neurons and neural oscillators. Input signals modulate the frequency of the neural encoder oscillators. These signals are then multiplexed using a network of rate-code neurons that has afferent Hebbian and lateral anti-Hebbian connectivity, termed as Lateral Anti Hebbian Network (LAHN). Finally the LAHN output is de-multiplexed using an output neural layer which is a combination of adaptive Hopf and Kuramoto oscillators for the signal reconstruction. The Kuramoto-Hopf combination performing demodulation is a novel way of describing a neural phase-locked loop. The proposed model is tested using both synthetic signals and real world EEG signals. The proposed model arises out of the general motivation to construct biologically inspired, oscillatory versions of some of the standard neural network models, and presents itself as an autoencoder network based on oscillatory neurons applicable to time series signals. As a demonstration, the model is applied to compression of EEG signals.
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Affiliation(s)
- Karthik Soman
- Bhupat and Jyoti Mehta School of Biosciences, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Vignesh Muralidharan
- Department of Psychology, University of California, San Diego, San Diego, CA, United States
| | - V. Srinivasa Chakravarthy
- Bhupat and Jyoti Mehta School of Biosciences, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
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Clinical Applications of Stochastic Dynamic Models of the Brain, Part I: A Primer. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2017. [PMID: 29528293 DOI: 10.1016/j.bpsc.2017.01.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Biological phenomena arise through interactions between an organism's intrinsic dynamics and stochastic forces-random fluctuations due to external inputs, thermal energy, or other exogenous influences. Dynamic processes in the brain derive from neurophysiology and anatomical connectivity; stochastic effects arise through sensory fluctuations, brainstem discharges, and random microscopic states such as thermal noise. The dynamic evolution of systems composed of both dynamic and random effects can be studied with stochastic dynamic models (SDMs). This article, Part I of a two-part series, offers a primer of SDMs and their application to large-scale neural systems in health and disease. The companion article, Part II, reviews the application of SDMs to brain disorders. SDMs generate a distribution of dynamic states, which (we argue) represent ideal candidates for modeling how the brain represents states of the world. When augmented with variational methods for model inversion, SDMs represent a powerful means of inferring neuronal dynamics from functional neuroimaging data in health and disease. Together with deeper theoretical considerations, this work suggests that SDMs will play a unique and influential role in computational psychiatry, unifying empirical observations with models of perception and behavior.
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Boonstra TW, Farmer SF, Breakspear M. Using Computational Neuroscience to Define Common Input to Spinal Motor Neurons. Front Hum Neurosci 2016; 10:313. [PMID: 27445753 PMCID: PMC4914567 DOI: 10.3389/fnhum.2016.00313] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/08/2016] [Indexed: 01/21/2023] Open
Affiliation(s)
- Tjeerd W Boonstra
- Black Dog Institute, University of New South WalesSydney, NSW, Australia; Systems Neuroscience Group, QIMR Berghofer Medical Research InstituteBrisbane, QLD, Australia
| | - Simon F Farmer
- Sobell Department of Motor Neuroscience and Movement Disorders, University College LondonLondon, UK; National Hospital for Neurology and NeurosurgeryLondon, UK
| | - Michael Breakspear
- Systems Neuroscience Group, QIMR Berghofer Medical Research InstituteBrisbane, QLD, Australia; Metro North Mental Health Service, Royal Brisbane and Women's HospitalBrisbane, QLD, Australia
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Boonstra TW, Danna-Dos-Santos A, Xie HB, Roerdink M, Stins JF, Breakspear M. Muscle networks: Connectivity analysis of EMG activity during postural control. Sci Rep 2015; 5:17830. [PMID: 26634293 PMCID: PMC4669476 DOI: 10.1038/srep17830] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/06/2015] [Indexed: 01/08/2023] Open
Abstract
Understanding the mechanisms that reduce the many degrees of freedom in the musculoskeletal system remains an outstanding challenge. Muscle synergies reduce the dimensionality and hence simplify the control problem. How this is achieved is not yet known. Here we use network theory to assess the coordination between multiple muscles and to elucidate the neural implementation of muscle synergies. We performed connectivity analysis of surface EMG from ten leg muscles to extract the muscle networks while human participants were standing upright in four different conditions. We observed widespread connectivity between muscles at multiple distinct frequency bands. The network topology differed significantly between frequencies and between conditions. These findings demonstrate how muscle networks can be used to investigate the neural circuitry of motor coordination. The presence of disparate muscle networks across frequencies suggests that the neuromuscular system is organized into a multiplex network allowing for parallel and hierarchical control structures.
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Affiliation(s)
- Tjeerd W Boonstra
- MOVE Research Institute Amsterdam, VU University, Amsterdam, The Netherlands.,Black Dog Institute, University of New South Wales, Sydney, Australia
| | | | - Hong-Bo Xie
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, Brisbane, Australia
| | - Melvyn Roerdink
- MOVE Research Institute Amsterdam, VU University, Amsterdam, The Netherlands
| | - John F Stins
- MOVE Research Institute Amsterdam, VU University, Amsterdam, The Netherlands
| | - Michael Breakspear
- Black Dog Institute, University of New South Wales, Sydney, Australia.,QIMR Berghofer Medical Research Institute, Brisbane, Australia
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