scholarly journals Context-specific modulation of intrinsic coupling modes shapes multisensory processing

2019 ◽  
Author(s):  
Edgar E. Galindo-Leon ◽  
Iain Stitt ◽  
Florian Pieper ◽  
Thomas Stieglitz ◽  
Gerhard Engler ◽  
...  
Keyword(s):  
Multisensory Integration ◽  
Large Scale ◽  
Multisensory Processing ◽  
Field Potential ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Extrinsic Factors ◽  
Sensory Inputs ◽  
Audiovisual Stimulation ◽  
Context Specific

AbstractIntrinsically generated patterns of coupled neuronal activity are associated with the dynamics of specific brain states. Sensory inputs are extrinsic factors that can perturb these intrinsic coupling modes, creating a complex scenario in which forthcoming stimuli are processed. Studying this intrinsic-extrinsic interplay is necessary to better understand perceptual integration and selection. Here, we show that this interplay leads to a reconfiguration of functional cortical connectivity that acts as a mechanism to facilitate stimulus processing. Using audiovisual stimulation in anesthetized ferrets, we found that this reconfiguration of coupling modes is context-specific, depending on long-term modulation by repetitive sensory inputs. These reconfigured coupling modes, in turn, lead to changes in latencies and power of local field potential responses that support multisensory integration. Our study demonstrates that this interplay extends across multiple time scales and involves different types of intrinsic coupling. These results suggest a novel large-scale mechanism that facilitates multisensory integration.

scholarly journals Context-specific modulation of intrinsic coupling modes shapes multisensory processing

2019 ◽  
Vol 5 (4) ◽  
pp. eaar7633 ◽  
Author(s):  
Edgar E. Galindo-Leon ◽  
Iain Stitt ◽  
Florian Pieper ◽  
Thomas Stieglitz ◽  
Gerhard Engler ◽  
...  
Keyword(s):  
Multisensory Integration ◽  
Large Scale ◽  
Multisensory Processing ◽  
Field Potential ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Extrinsic Factors ◽  
Sensory Inputs ◽  
Audiovisual Stimulation ◽  
Context Specific

Intrinsically generated patterns of coupled neuronal activity are associated with the dynamics of specific brain states. Sensory inputs are extrinsic factors that can perturb these intrinsic coupling modes, creating a complex scenario in which forthcoming stimuli are processed. Studying this intrinsic-extrinsic interplay is necessary to better understand perceptual integration and selection. Here, we show that this interplay leads to a reconfiguration of functional cortical connectivity that acts as a mechanism to facilitate stimulus processing. Using audiovisual stimulation in anesthetized ferrets, we found that this reconfiguration of coupling modes is context specific, depending on long-term modulation by repetitive sensory inputs. These reconfigured coupling modes lead to changes in latencies and power of local field potential responses that support multisensory integration. Our study demonstrates that this interplay extends across multiple time scales and involves different types of intrinsic coupling. These results suggest a previously unknown large-scale mechanism that facilitates multisensory integration.

scholarly journals On the multiple time scales of variability in the Northeast Pacific Ocean

Ocean Science ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 591-605
Author(s):  
R. Tokmakian
Keyword(s):  
Pacific Ocean ◽  
Large Scale ◽  
Southern Oscillation ◽  
Set Covering ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Data Set ◽  
Northeast Pacific ◽  
Energy Signal ◽  
Northeast Pacific Ocean

Abstract. The spatial and temporal sea surface height energy distribution of the Northeast Pacific Ocean is described and discussed. Using an altimetric data set covering 15 years (1993–2007), the energy within the 3–9 month band is primarily located within 10° of the coast. In the Gulf of Alaska, this energy signal is on the shelf, while further south, west of the California/Oregon coast, the significant energy in this band is west of the shelf break. In both cases, it is primarily forced by the local wind. Within the 2–3 year band, the signal reflects energy generated by local changes to the wind stress from large atmospheric shifts indicated by the Pacific North American Index and by advective or propagating processes related to El Niño-Southern Oscillation. Over the two 4–6 year periods within this data set, the change is primarily due to the large scale shift in atmospheric systems north of about 30° N which also affect changes in current strengths. Based on the distribution of the energy signal and its variability, a set of three winter-time indices are suggested to characterize the distinct differences in the SSH anomalies in these areas.

scholarly journals An Assessment of GCM Skill in Simulating Persistence across Multiple Time Scales

2011 ◽  
Vol 24 (14) ◽  
pp. 3609-3623 ◽  
Author(s):  
Fiona Johnson ◽  
Seth Westra ◽  
Ashish Sharma ◽  
Andrew J. Pitman
Keyword(s):  
Interannual Variability ◽  
General Circulation ◽  
Large Scale ◽  
Low Frequency ◽  
General Circulation Models ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Max Planck ◽  
Reservoir Storage ◽  
Low Frequency Variability

Abstract Climate change impact studies for water resource applications, such as the development of projections of reservoir yields or the assessment of likely frequency and amplitude of drought under a future climate, require that the year-to-year persistence in a range of hydrological variables such as catchment average rainfall be properly represented. This persistence is often attributable to low-frequency variability in the global sea surface temperature (SST) field and other large-scale climate variables through a complex sequence of teleconnections. To evaluate the capacity of general circulation models (GCMs) to accurately represent this low-frequency variability, a set of wavelet-based skill measures has been developed to compare GCM performance in representing interannual variability with the observed global SST data, as well as to assess the extent to which this variability is imparted in precipitation and surface pressure anomaly fields. A validation of the derived skill measures is performed using GCM precipitation as an input in a reservoir storage context, with the accuracy of reservoir storage estimates shown to be improved by using GCM outputs that correctly represent the observed low-frequency variability. Significant differences in the performance of different GCMs is demonstrated, suggesting that judicious selection of models is required if the climate impact assessment is sensitive to low-frequency variability. The two GCMs that were found to exhibit the most appropriate representation of global low-frequency variability for individual variables assessed were the Istituto Nazionale di Geofisica e Vulcanologia (INGV) ECHAM4 and L’Institut Pierre-Simon Laplace Coupled Model, version 4 (IPSL CM4); when considering all three variables, the Max Planck Institute (MPI) ECHAM5 performed well. Importantly, models that represented interannual variability well for SST also performed well for the other two variables, while models that performed poorly for SST also had consistently low skill across the remaining variables.

Cyber physics system: a review

2018 ◽  
Vol 38 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Changbin Jiang ◽  
Ying Ma ◽  
Hong Chen ◽  
Yangyin Zheng ◽  
Shan Gao ◽  
...  
Keyword(s):  
Large Scale ◽  
Research Area ◽  
Smart Manufacturing ◽  
Multiple Time Scales ◽  
Future Research ◽  
Multiple Time ◽  
Medical Systems ◽  
Daily Lives ◽  
Content Type ◽  
Control Circuits

Purpose Cyber physical system (CPS) has attracted much attention from industry, government and academia due to its dramatic impact on society, economy and people’s daily lives. Scholars have conducted a number of studies on CPS. However, despite of the dynamic nature of this research area, a systematic and extensive review of recent research on CPS is unavailable. Accordingly, this paper conducts an intensive literature review on CPS and presents an overview of existing research on CPS. The purpose of this paper is to identify the challenges of studying CPS as well as the directions for future studies on CPS. Design/methodology/approach This paper examines existing literatures about CPS from 2006 to 2018 in Compendex, presenting its definition, architectures, characteristics and applications. Findings This study finds that CPS is closely integrated, diversified and large-scale network with complex multiple time scales. It requires dynamic reorganization/reconfiguration, mass computing, and closed, automated and control circuits. Currently, CPS has been applied in smart manufacturing, medical systems, smart city and smart libraries. The main challenges in designing CPS are to develop, to modify, to integrate abstractions and to set predictable timing of openness and physical interconnection of physical devices. Furthermore, security is a key issue in CPS. Originality/value This study adds knowledge to the existing literature of CPS by answering what the current level of development on CPS is and what the potential future research directions of CPS are.

scholarly journals Unsupervised detection of cell-assembly sequences with edit similarity score

2017 ◽  
Author(s):  
Keita Watanabe ◽  
Tatsuya Haga ◽  
David R Euston ◽  
Masami Tatsuno ◽  
Tomoki Fukai
Keyword(s):  
Large Scale ◽  
Clustering Algorithms ◽  
Spike Timing ◽  
Neural Population ◽  
Multiple Time Scales ◽  
Cell Assembly ◽  
Multiple Time ◽  
Mathematical Methods ◽  
Population Activity ◽  
Assembly Sequences

SUMMARYCell assembly is a hypothetical functional unit of information processing in the brain. While technologies for recording large-scale neural activity have been advanced, mathematical methods to analyze sequential activity patterns of cell-assembly are severely limited. Here, we propose a method to extract cell-assembly sequences repeated at multiple time scales and various precisions from irregular neural population activity. The key technology is to combine “edit similarity” in computer science with machine-learning clustering algorithms, where the former defines a “distance” between two strings as the minimal number of operations required to transform one string to the other. Our method requires no external references for pattern detection, and is tolerant of spike timing jitters and length irregularity in assembly sequences. These virtues enabled simultaneous automatic detections of hippocampal place-cell sequences during locomotion and their time-compressed replays during resting states. Furthermore, our method revealed previously undetected cell-assembly structure in the rat prefrontal cortex during goal-directed behavior. Thus, our method expands the horizon of cell-assembly analysis.

scholarly journals Large scale singularly perturbed boundary value problems

1989 ◽  
Vol 2 (3) ◽  
pp. 139-167
Author(s):  
M. Kathirkamanayagan ◽  
G. S. Ladde
Keyword(s):  
Large Scale ◽  
Original System ◽  
Singularly Perturbed ◽  
Multiple Time Scales ◽  
Diagonal Form ◽  
Multiple Time ◽  
Modern Technique ◽  
Alternative Approach ◽  
Decomposition Processes ◽  
Singular Transformation

In this paper an alternative approach to the method of asymptotic expansions for the study of a singularly perturbed linear system with multiparameters and multiple time scales is developed. The method consists of developing a linear non-singular transformation that transforms an arbitrary n—time scale system into a diagonal form. Furthermore, a dichotomy transformation is employed to decompose the faster subsystems into stable and unstable modes. Fast, slow, stable and unstable modes decomposition processes provide a modern technique to find an approximate solution of the original system in terms of the solution of an auxiliary system. This method yields a constructive and computationally attractive way to investigate the system.

Audio-Visual Multisensory Integration in Superior Parietal Lobule Revealed by Human Intracranial Recordings

2006 ◽  
Vol 96 (2) ◽  
pp. 721-729 ◽  
Author(s):  
Sophie Molholm ◽  
Pejman Sehatpour ◽  
Ashesh D. Mehta ◽  
Marina Shpaner ◽  
Manuel Gomez-Ramirez ◽  
...  
Keyword(s):  
Multisensory Integration ◽  
Visual Stimulation ◽  
Multisensory Processing ◽  
Human Subjects ◽  
Superior Parietal Lobule ◽  
Sensory Inputs ◽  
Visual Inputs ◽  
Parietal Lobule ◽  
Intracranial Recordings

Intracranial recordings from three human subjects provide the first direct electrophysiological evidence for audio-visual multisensory processing in the human superior parietal lobule (SPL). Auditory and visual sensory inputs project to the same highly localized region of the parietal cortex with auditory inputs arriving considerably earlier (30 ms) than visual inputs (75 ms). Multisensory integration processes in this region were assessed by comparing the response to simultaneous audio-visual stimulation with the algebraic sum of responses to the constituent auditory and visual unisensory stimulus conditions. Significant integration effects were seen with almost identical morphology across the three subjects, beginning between 120 and 160 ms. These results are discussed in the context of the role of SPL in supramodal spatial attention and sensory-motor transformations.

scholarly journals Large-scale user modeling with recurrent neural networks for music discovery on multiple time scales

2017 ◽  
Vol 77 (12) ◽  
pp. 15385-15407 ◽  
Author(s):  
Cedric De Boom ◽  
Rohan Agrawal ◽  
Samantha Hansen ◽  
Esh Kumar ◽  
Romain Yon ◽  
...  
Keyword(s):  
Neural Networks ◽  
Time Scales ◽  
Recurrent Neural Networks ◽  
User Modeling ◽  
Large Scale ◽  
Multiple Time Scales ◽  
Multiple Time

scholarly journals Network asynchrony underlying increased broadband gamma power

2020 ◽  
Author(s):  
Nicolas Guyon ◽  
Leonardo Rakauskas Zacharias ◽  
Eliezyer Fermino de Oliveira ◽  
Hoseok Kim ◽  
João Pereira Leite ◽  
...  
Keyword(s):  
Field Potential ◽  
Gamma Band ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Potential Oscillations ◽  
Spectral Leakage ◽  
Gamma Power ◽  
Gamma Rhythms ◽  
Brain States

AbstractSynchronous activity of cortical inhibitory interneurons expressing parvalbumin (PV) underlies the expression of cortical gamma rhythms. Paradoxically, deficient PV inhibition is associated with increased broadband gamma power. Increased baseline broadband gamma is also a prominent characteristic in schizophrenia, and a hallmark of network alterations induced by N-methyl-D-aspartate receptor (NMDAR) antagonists such as ketamine. It has been questioned if enhanced broadband gamma power is a true rhythm, and if rhythmic PV inhibition is involved or not. It has been suggested that asynchronous and increased firing activities underlie broadband power increases spanning the gamma band. Using mice lacking NMDAR activity specifically in PV neurons to model deficient PV inhibition, we here show that local LFP (local field potential) oscillations and neuronal activity with decreased synchronicity generate increases in prefrontal broadband gamma power. Specifically, reduced spike time precision of both local PV interneurons and wide-spiking (WS) excitatory neurons contribute to increased firing rates, and spectral leakage of spiking activity (spike “contamination”) affecting the broadband gamma band. Desynchronization was evident at multiple time scales, with reduced spike-LFP entrainment, reduced cross-frequency coupling, and fragmentation of brain states. While local application of S(+)-ketamine in wildtype mice triggered network desynchronization and increases in broadband gamma power, our investigations suggest that disparate mechanisms underlie increased power of broadband gamma caused by genetic alteration of PV interneurons, and ketamine-induced power increases in broadband gamma. Our studies, thus, confirm that broadband gamma increases can arise from asynchronous activities, and demonstrate that long-term deficiency of PV inhibition can be a contributor.

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