1
|
Wilson LE, Castanheira JDS, Kinder BL, Baillet S. Model selection for spectral parameterization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.01.606216. [PMID: 39149403 PMCID: PMC11326208 DOI: 10.1101/2024.08.01.606216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Neurophysiological brain activity comprises rhythmic (periodic) and arrhythmic (aperiodic) signal elements, which are increasingly studied in relation to behavioral traits and clinical symptoms. Current methods for spectral parameterization of neural recordings rely on user-dependent parameter selection, which challenges the replicability and robustness of findings. Here, we introduce a principled approach to model selection, relying on Bayesian information criterion, for static and time-resolved spectral parameterization of neurophysiological data. We present extensive tests of the approach with ground-truth and empirical magnetoencephalography recordings. Data-driven model selection enhances both the specificity and sensitivity of spectral and spectrogram decompositions, even in non-stationary contexts. Overall, the proposed spectral decomposition with data-driven model selection minimizes the reliance on user expertise and subjective choices, enabling more robust, reproducible, and interpretable research findings.
Collapse
Affiliation(s)
| | | | | | - Sylvain Baillet
- Montreal Neurological Institute, McGill University, Montreal QC, Canada
| |
Collapse
|
2
|
McCormick EM, Kievit RA. Poorer White Matter Microstructure Predicts Slower and More Variable Reaction Time Performance: Evidence for a Neural Noise Hypothesis in a Large Lifespan Cohort. J Neurosci 2023; 43:3557-3566. [PMID: 37028933 PMCID: PMC10184733 DOI: 10.1523/jneurosci.1042-22.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 04/09/2023] Open
Abstract
Most prior research has focused on characterizing averages in cognition, brain characteristics, or behavior, and attempting to predict differences in these averages among individuals. However, this overwhelming focus on mean levels may leave us with an incomplete picture of what drives individual differences in behavioral phenotypes by ignoring the variability of behavior around an individual's mean. In particular, enhanced white matter (WM) structural microstructure has been hypothesized to support consistent behavioral performance by decreasing Gaussian noise in signal transfer. Conversely, lower indices of WM microstructure are associated with greater within-subject variance in the ability to deploy performance-related resources, especially in clinical populations. We tested a mechanistic account of the "neural noise" hypothesis in a large adult lifespan cohort (Cambridge Centre for Ageing and Neuroscience) with over 2500 adults (ages 18-102; 1508 female; 1173 male; 2681 behavioral sessions; 708 MRI scans) using WM fractional anisotropy to predict mean levels and variability in reaction time performance on a simple behavioral task using a dynamic structural equation model. By modeling robust and reliable individual differences in within-person variability, we found support for a neural noise hypothesis (Kail, 1997), with lower fractional anisotropy predicted individual differences in separable components of behavioral performance estimated using dynamic structural equation model, including slower mean responses and increased variability. These effects remained when including age, suggesting consistent effects of WM microstructure across the adult lifespan unique from concurrent effects of aging. Crucially, we show that variability can be reliably separated from mean performance using advanced modeling tools, enabling tests of distinct hypotheses for each component of performance.SIGNIFICANCE STATEMENT Human cognitive performance is defined not just by the long-run average, but trial-to-trial variability around that average. However, investigations of cognitive abilities and changes during aging have largely ignored this variability component of behavior. We provide evidence that white matter (WM) microstructure predicts individual differences in mean performance and variability in a sample spanning the adult lifespan (18-102). Unlike prior studies of cognitive performance and variability, we modeled variability directly and distinct from mean performance using a dynamic structural equation model, which allows us to decouple variability from mean performance and other complex features of performance (e.g., autoregression). The effects of WM were robust above the effect of age, highlighting the role of WM in promoting fast and consistent performance.
Collapse
Affiliation(s)
- Ethan M McCormick
- Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GD Nijmegen, The Netherlands
- Methodology and Statistics Department, Institute of Psychology, Leiden University, 2333 AK Leiden, The Netherlands
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, North Carolina, 27599
| | - Rogier A Kievit
- Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GD Nijmegen, The Netherlands
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, United Kingdom
| |
Collapse
|
3
|
Wang P, Lingo VanGilder J, Schweighofer N, Schaefer SY. Rey-Osterrieth complex figure recall scores and motor skill learning in older adults: A non-linear mixed effect model-based analysis. Hum Mov Sci 2022; 86:103004. [PMID: 36191575 PMCID: PMC11285843 DOI: 10.1016/j.humov.2022.103004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/18/2022] [Accepted: 09/24/2022] [Indexed: 11/04/2022]
Abstract
Age-related declines in motor learning are well documented. Visuospatial memory has been proposed as a key factor explaining age-related declines in sensorimotor adaptation, but most studies have not used standardized visuospatial memory tests nor controlled for age-related visuospatial memory declines. The present study explores the relationship between visuospatial memory and motor learning in older adults while also controlling for age and utilizing a standardized visuospatial memory test. Forty-nine nondemented older adults repetitively practiced a functional upper-extremity motor task and were re-assessed one week later. Training data were modeled with mixed-effect exponential decay functions, with parameters representing amount of performance change, rate of improvement, and final performance. Age and visuospatial memory were included as possible covariates for the parameter measuring rate of improvement (τ). After controlling for age, higher visuospatial memory scores were associated with faster rates of skill acquisition and better short-term retention one week later. These associations with visuospatial memory were dependent, however, on the level of initial skill. These findings suggest that the extent of re-learning motor skills in geriatric physical rehabilitation may depend on intact visuospatial memory.
Collapse
Affiliation(s)
- Peiyuan Wang
- School of Biological and Health Systems Engineering, Arizona State University, USA
| | | | | | - Sydney Y Schaefer
- School of Biological and Health Systems Engineering, Arizona State University, USA.
| |
Collapse
|
4
|
TDCS effects on pointing task learning in young and old adults. Sci Rep 2021; 11:3421. [PMID: 33564052 PMCID: PMC7873227 DOI: 10.1038/s41598-021-82275-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/14/2021] [Indexed: 01/19/2023] Open
Abstract
Skill increase in motor performance can be defined as explicitly measuring task success but also via more implicit measures of movement kinematics. Even though these measures are often related, there is evidence that they represent distinct concepts of learning. In the present study, the effect of multiple tDCS-sessions on both explicit and implicit measures of learning are investigated in a pointing task in 30 young adults (YA) between 27.07 ± 3.8 years and 30 old adults (OA) between 67.97 years ± 5.3 years. We hypothesized, that OA would show slower explicit skill learning indicated by higher movement times/lower accuracy and slower implicit learning indicated by higher spatial variability but profit more from anodal tDCS compared with YA. We found age-related differences in movement time but not in accuracy or spatial variability. TDCS did not skill learning facilitate learning neither in explicit nor implicit parameters. However, contrary to our hypotheses, we found tDCS-associated higher accuracy only in YA but not in spatial variability. Taken together, our data shows limited overlapping of tDCS effects in explicit and implicit skill parameters. Furthermore, it supports the assumption that tDCS is capable of producing a performance-enhancing brain state at least for explicit skill acquisition.
Collapse
|
5
|
Hupfeld KE, Swanson CW, Fling BW, Seidler RD. TMS-induced silent periods: A review of methods and call for consistency. J Neurosci Methods 2020; 346:108950. [PMID: 32971133 PMCID: PMC8276277 DOI: 10.1016/j.jneumeth.2020.108950] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/24/2020] [Accepted: 09/15/2020] [Indexed: 12/31/2022]
Abstract
Transcranial magnetic stimulation (TMS)-induced silent periods provide an in vivo measure of human motor cortical inhibitory function. Cortical silent periods (cSP, also sometimes referred to as contralateral silent periods) and ipsilateral silent periods (iSP) may change with advancing age and disease and can provide insight into cortical control of the motor system. The majority of past silent period work has implemented largely varying methodology, sometimes including subjective analyses and incomplete methods descriptions. This limits reproducibility of silent period work and hampers comparisons of silent period measures across studies. Here, we discuss methodological differences in past silent period work, highlighting how these choices affect silent period outcome measures. We also outline challenges and possible solutions for measuring silent periods in the unique case of the lower limbs. Finally, we provide comprehensive recommendations for collection, analysis, and reporting of future silent period studies.
Collapse
Affiliation(s)
- K E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - C W Swanson
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - B W Fling
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA; Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO, USA
| | - R D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
6
|
Knol H, Huys R, Temprado JJ, Sleimen-Malkoun R. Performance, complexity and dynamics of force maintenance and modulation in young and older adults. PLoS One 2019; 14:e0225925. [PMID: 31821334 PMCID: PMC6903729 DOI: 10.1371/journal.pone.0225925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/15/2019] [Indexed: 01/27/2023] Open
Abstract
The present study addresses how task constraints and aging influence isometric force control. We used two tasks requiring either force maintenance (straight line target force) or force modulation (sine-wave target force) around different force levels and at different modulation frequencies. Force levels were defined relative the individual maximum voluntary contraction. A group of young adults (mean age ± SD = 25 ± 3.6 years) and a group of elderly (mean age = 77 ± 6.4 years) took part in the study. Age- and task-related effects were assessed through differences in: (i) force control accuracy, (ii) time-structure of force fluctuations, and (iii) the contribution of deterministic (predictable) and stochastic (noise-like) dynamic components to the expressed behavior. Performance-wise, the elderly showed a pervasive lower accuracy and higher variability than the young participants. The analysis of fluctuations showed that the elderly produced force signals that were less complex than those of the young adults during the maintenance task, but the reverse was observed in the modulation task. Behavioral complexity results suggest a reduced adaptability to task-constraints with advanced age. Regarding the dynamics, we found comparable generating mechanisms in both age groups for both tasks and in all conditions, namely a fixed-point for force maintenance and a limit-cycle for force modulation. However, aging increased the stochasticity (noise-driven fluctuations) of force fluctuations in the cyclic force modulation, which could be related to the increased complexity found in elderly for this same task. To our knowledge this is the first time that these different perspectives to motor control are used simultaneously to characterize force control capacities. Our findings show their complementarity in revealing distinct aspects of sensorimotor adaptation to task constraints and age-related declines. Although further research is still needed to identify the physiological underpinnings, the used task and methodology are shown to have both fundamental and clinical applications.
Collapse
Affiliation(s)
- Hester Knol
- Institut des Sciences du Mouvement, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université, Marseille, France
- Department of Applied Cognitive Psychology, Universität Ulm, Ulm, Germany
| | - Raoul Huys
- Centre de Recherche Cerveau & Cognition, UPS, CHU Purpan, Université de Toulouse, Toulouse, France
| | - Jean-Jacques Temprado
- Institut des Sciences du Mouvement, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université, Marseille, France
| | - Rita Sleimen-Malkoun
- Institut des Sciences du Mouvement, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université, Marseille, France
| |
Collapse
|
7
|
Pertermann M, Mückschel M, Adelhöfer N, Ziemssen T, Beste C. On the interrelation of 1/ f neural noise and norepinephrine system activity during motor response inhibition. J Neurophysiol 2019; 121:1633-1643. [PMID: 30811254 DOI: 10.1152/jn.00701.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Several lines of evidence suggest that there is a close interrelation between the degree of noise in neural circuits and the activity of the norepinephrine (NE) system, yet the precise nexus between these aspects is far from being understood during human information processing and cognitive control in particular. We examine this nexus during response inhibition in n = 47 healthy participants. Using high-density EEG recordings, we estimate neural noise by calculating "1/f noise" of those data and integrate these EEG parameters with pupil diameter data as an established indirect index of NE system activity. We show that neural noise is reduced when cognitive control processes to inhibit a prepotent/automated response are exerted. These neural noise variations were confined to the theta frequency band, which has also been shown to play a central role during response inhibition and cognitive control. There were strong positive correlations between the 1/f neural noise parameter and the pupil diameter data within the first 250 ms after the Nogo stimulus presentation at centro-parietal electrode sites. No such correlations were evident during automated responding on Go trials. Source localization analyses using standardized low-resolution brain electromagnetic tomography show that inferior parietal areas are activated in this time period in Nogo trials. The data suggest an interrelation of NE system activity and neural noise within early stages of information processing associated with inferior parietal areas when cognitive control processes are required. The data provide the first direct evidence for the nexus between NE system activity and the modulation of neural noise during inhibitory control in humans. NEW & NOTEWORTHY This is the first study showing that there is a nexus between norepinephrine system activity and the modulation of neural noise or scale-free neural activity during inhibitory control in humans. It does so by integrating pupil diameter data with analysis of EEG neural noise.
Collapse
Affiliation(s)
- Maik Pertermann
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden , Germany
| | - Moritz Mückschel
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden , Germany.,MS Centre Dresden, Centre of Clinical Neuroscience, Department of Neurology, Faculty of Medicine, TU Dresden, Dresden , Germany
| | - Nico Adelhöfer
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden , Germany
| | - Tjalf Ziemssen
- MS Centre Dresden, Centre of Clinical Neuroscience, Department of Neurology, Faculty of Medicine, TU Dresden, Dresden , Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden , Germany.,Faculty of Psychology, School of Science, TU Dresden, Dresden , Germany
| |
Collapse
|
8
|
Vieluf S, Mora K, Gölz C, Reuter EM, Godde B, Dellnitz M, Reinsberger C, Voelcker-Rehage C. Age- and Expertise-Related Differences of Sensorimotor Network Dynamics during Force Control. Neuroscience 2018; 388:203-213. [DOI: 10.1016/j.neuroscience.2018.07.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/23/2018] [Accepted: 07/14/2018] [Indexed: 10/28/2022]
|
9
|
Castronovo AM, Mrachacz-Kersting N, Stevenson AJT, Holobar A, Enoka RM, Farina D. Decrease in force steadiness with aging is associated with increased power of the common but not independent input to motor neurons. J Neurophysiol 2018; 120:1616-1624. [PMID: 29975167 DOI: 10.1152/jn.00093.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Declines in motor function with advancing age have been attributed to changes occurring at all levels of the neuromuscular system. However, the impact of aging on the control of muscle force by spinal motor neurons is not yet understood. In this study on 20 individuals aged between 24 and 75 yr (13 men, 7 women), we investigated the common synaptic input to motor neurons of the tibialis anterior muscle and its impact on force control. Motor unit discharge times were identified from high-density surface EMG recordings during isometric contractions at forces of 20% of maximal voluntary effort. Coherence analysis between motor unit spike trains was used to characterize the input to motor neurons. The decrease in force steadiness with age ( R2 = 0.6, P < 0.01) was associated with an increase in the amplitude of low-frequency oscillations of functional common synaptic input to motor neurons ( R2 = 0.59; P < 0.01). The relative proportion of common input to independent noise at low frequencies increased with variability (power) in common synaptic input. Moreover, variability in interspike interval did not change and strength of the common input in the gamma band decreased with age ( R2 = 0.22; P < 0.01). The findings indicate that age-related reduction in the accuracy of force control is associated with increased common fluctuations to motor neurons at low frequencies and not with an increase in independent synaptic input. NEW & NOTEWORTHY The influence of aging on the role of spinal motor neurons in accurate force control is not yet understood. We demonstrate that aging is associated with increased oscillations in common input to motor neurons at low frequencies and with a decrease in the relative strength of gamma oscillations. These results demonstrate that the synaptic inputs to motor neurons change across the life span and contribute to a decline in force control.
Collapse
Affiliation(s)
| | | | | | - Ales Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor , Maribor , Slovenia
| | - Roger Maro Enoka
- Department of Integrative Physiology, University of Colorado , Boulder, Colorado
| | - Dario Farina
- Department of Bioengineering, Imperial College London , London , United Kingdom
| |
Collapse
|
10
|
Oomen NM, van Dieën JH. Effects of age on force steadiness: A literature review and meta-analysis. Ageing Res Rev 2017; 35:312-321. [PMID: 27836706 DOI: 10.1016/j.arr.2016.11.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/04/2016] [Indexed: 11/25/2022]
Abstract
The variability of force is indicative of the biological variability inherent in the human motor system. Previous literature showed inconsistent findings of the effect of age on the variability of force and hence a systematic review was performed. Twenty studies were included in this systematic review, of which twelve provided sufficient data to determine effect sizes for the effect of age. After determining the pooled effect size, the effect of sample size on dichotomized effect sizes (significant vs. non-significant) was determined. Also, the effect of possible determinants, age difference between age groups, dominance of investigated limb, muscle group, muscle location (proximal vs. distal and upper vs. lower extremity) and target force level on effect size (categorized as small, medium, or large) were investigated. A large pooled effect size of age was found (rtotal=0.67, 95% CI [0.61; 0.72]). No relation between sample size and effect size significance was found, indicative of no lack of power in the studies reviewed. No relations were found of associations between age difference, upper vs. lower extremity muscle location, and dominance and effect size. Significant relations of effect size with muscle group, proximal vs. distal muscle location and target force level were found. Also, an interaction effect of muscle group and target force level was suggested. The meta-analysis results are in line with motor unit loss as the main cause of the effect of ageing on force steadiness and this effect can partially explain decreased motor performance associated with ageing.
Collapse
|
11
|
Lefebvre S, Liew SL. Anatomical Parameters of tDCS to Modulate the Motor System after Stroke: A Review. Front Neurol 2017; 8:29. [PMID: 28232816 PMCID: PMC5298973 DOI: 10.3389/fneur.2017.00029] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 01/23/2017] [Indexed: 01/19/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method to modulate the local field potential in neural tissue and consequently, cortical excitability. As tDCS is relatively portable, affordable, and accessible, the applications of tDCS to probe brain-behavior connections have rapidly increased in the last 10 years. One of the most promising applications is the use of tDCS to modulate excitability in the motor cortex after stroke and promote motor recovery. However, the results of clinical studies implementing tDCS to modulate motor excitability have been highly variable, with some studies demonstrating that as many as 50% or more of patients fail to show a response to stimulation. Much effort has therefore been dedicated to understand the sources of variability affecting tDCS efficacy. Possible suspects include the placement of the electrodes, task parameters during stimulation, dosing (current amplitude, duration of stimulation, frequency of stimulation), individual states (e.g., anxiety, motivation, attention), and more. In this review, we first briefly review potential sources of variability specific to stroke motor recovery following tDCS. We then examine how the anatomical variability in tDCS placement [e.g., neural target(s) and montages employed] may alter the neuromodulatory effects that tDCS exerts on the post-stroke motor system.
Collapse
Affiliation(s)
- Stephanie Lefebvre
- Neural Plasticity and Neurorehabilitation Laboratory, Chan Division of Occupational Science and Occupational Therapy, Division of Biokinesiology and Physical Therapy, Department of Neurology, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Sook-Lei Liew
- Neural Plasticity and Neurorehabilitation Laboratory, Chan Division of Occupational Science and Occupational Therapy, Division of Biokinesiology and Physical Therapy, Department of Neurology, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
12
|
Quandt F, Bönstrup M, Schulz R, Timmermann JE, Zimerman M, Nolte G, Hummel FC. Spectral Variability in the Aged Brain during Fine Motor Control. Front Aging Neurosci 2016; 8:305. [PMID: 28066231 PMCID: PMC5175385 DOI: 10.3389/fnagi.2016.00305] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/30/2016] [Indexed: 01/08/2023] Open
Abstract
Physiological aging is paralleled by a decline of fine motor skills accompanied by structural and functional alterations of the underlying brain network. Here, we aim to investigate age-related changes in the spectral distribution of neuronal oscillations during fine skilled motor function. We employ the concept of spectral entropy in order to describe the flatness and peaked-ness of a frequency spectrum to quantify changes in the spectral distribution of the oscillatory motor response in the aged brain. Electroencephalogram was recorded in elderly (n = 32) and young (n = 34) participants who performed either a cued finger movement or a pinch or a whole hand grip task with their dominant right hand. Whereas young participant showed distinct, well-defined movement-related power decreases in the alpha and upper beta band, elderly participants exhibited a flat broadband, frequency-unspecific power desynchronization. This broadband response was reflected by an increase of spectral entropy over sensorimotor and frontal areas in the aged brain. Neuronal activation patterns differed between motor tasks in the young brain, while the aged brain showed a similar activation pattern in all tasks. Moreover, we found a wider recruitment of the cortical motor network in the aged brain. The present study adds to the understanding of age-related changes of neural coding during skilled motor behavior, revealing a less predictable signal with great variability across frequencies in a wide cortical motor network in the aged brain. The increase in entropy in the aged brain could be a reflection of random noise-like activity or could represent a compensatory mechanism that serves a functional role.
Collapse
Affiliation(s)
- Fanny Quandt
- BrainImaging and NeuroStimulation Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Marlene Bönstrup
- BrainImaging and NeuroStimulation Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Robert Schulz
- BrainImaging and NeuroStimulation Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Jan E Timmermann
- BrainImaging and NeuroStimulation Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Maximo Zimerman
- Institute of Neuroscience, Favaloro UniversityBuenos Aires, Argentina; Institute of Cognitive NeurologyBuenos Aires, Argentina
| | - Guido Nolte
- Department of Neurophysiology, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Friedhelm C Hummel
- BrainImaging and NeuroStimulation Laboratory, Department of Neurology, University Medical Center Hamburg-EppendorfHamburg, Germany; Institute of Neuroscience, Favaloro UniversityBuenos Aires, Argentina; Clinical Neuroengineering, Brain Mind Institute and Centre of Neuroprosthetics (CNP), Swiss Federal Institute of Technology (EPFL)Geneva, Switzerland; Clinique Romande de Réadaptation, Swiss Federal Institute of Technology (EPFL Valais)Sion, Switzerland
| |
Collapse
|
13
|
Abstract
Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15-53 years) and scalp EEG data from healthy younger (20-30 years) and older (60-70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <-1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. Significance statement: Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise-induced deficits in neural communication.
Collapse
|
14
|
Voytek B, Knight RT. Dynamic network communication as a unifying neural basis for cognition, development, aging, and disease. Biol Psychiatry 2015; 77:1089-97. [PMID: 26005114 PMCID: PMC4443259 DOI: 10.1016/j.biopsych.2015.04.016] [Citation(s) in RCA: 296] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 04/15/2015] [Accepted: 04/23/2015] [Indexed: 01/08/2023]
Abstract
Perception, cognition, and social interaction depend upon coordinated neural activity. This coordination operates within noisy, overlapping, and distributed neural networks operating at multiple timescales. These networks are built upon a structural scaffolding with intrinsic neuroplasticity that changes with development, aging, disease, and personal experience. In this article, we begin from the perspective that successful interregional communication relies upon the transient synchronization between distinct low-frequency (<80 Hz) oscillations, allowing for brief windows of communication via phase-coordinated local neuronal spiking. From this, we construct a theoretical framework for dynamic network communication, arguing that these networks reflect a balance between oscillatory coupling and local population spiking activity and that these two levels of activity interact. We theorize that when oscillatory coupling is too strong, spike timing within the local neuronal population becomes too synchronous; when oscillatory coupling is too weak, spike timing is too disorganized. Each results in specific disruptions to neural communication. These alterations in communication dynamics may underlie cognitive changes associated with healthy development and aging, in addition to neurological and psychiatric disorders. A number of neurological and psychiatric disorders-including Parkinson's disease, autism, depression, schizophrenia, and anxiety-are associated with abnormalities in oscillatory activity. Although aging, psychiatric and neurological disease, and experience differ in the biological changes to structural gray or white matter, neurotransmission, and gene expression, our framework suggests that any resultant cognitive and behavioral changes in normal or disordered states or their treatment are a product of how these physical processes affect dynamic network communication.
Collapse
Affiliation(s)
- Bradley Voytek
- Department of Cognitive Science, Neurosciences Graduate Program, and the Institute for Neural Computation, University of California, San Diego, La Jolla, California..
| | | |
Collapse
|
15
|
Nhouvannasak V, Clément S, Manto M. Trains of electrical stimulation of the trapezius muscles redistribute the frequencies of body oscillations during stance. Neurol Res 2015; 37:751-62. [PMID: 26004862 DOI: 10.1179/1743132815y.0000000051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We investigated the postural effects of trains of electrical stimulation (TES) applied unilaterally or bilaterally on the trapezius muscle in 20 healthy subjects (mean age: 23.1 ± 1.33 years; F/M: 8/12). The anterior-posterior (AP) displacements (AP axis), medio-lateral displacements (ML axis) and total travelled distances (TTW) of the centre of pressure (COP) remained unchanged with TES. However, detailed spectral analysis of COP oscillations revealed a marked decrease of the magnitudes of peak power spectral density (peak PSD) following application of TES. Peak PSD was highly correlated with the intensity of stimulation (P < 0.001 both the AP and ML axes). For the AP axis, the integrals of the sub-bands 0-0.4, 0.4-1.5, 1.5-3 Hz were significantly decreased (P < 0.001), the integrals of the sub-bands 3-5 and 5-8 Hz were not significantly affected (P>0.30) and the integrals of the sub-band 8-10 Hz were significantly increased (P < 0.001). The ratios of the integrals of sub-bands 8-10 Hz/0-3 Hz were markedly enhanced with bilateral TES (P < 0.001). For the ML axis, the effects were striking (P < 0.001) for the sub-bands 0-0.4, 0.4-1.5 and 8-10 Hz. For both the AP and ML axes, a significant inverse linear relationship was found between the intensity of TES and the average speed of COP. We show that TES applied over the trapezius muscles exerts significant and so far unrecognised effects upon oscillations of the COP, decreasing low-frequency oscillations and enhancing high-frequency oscillations. Our data unravel a novel property of the trapezius muscles upon postural control. We suggest that this muscle plays a role of a distributor of low-frequency versus high-frequency sub-bands of frequency during stance. Previous studies have shown that patients with supra-tentorial stroke show an increased peak PSD in low frequencies of body oscillations. Therefore, our findings provide a rationale to assess neurostimulation of the trapezius muscle in the rehabilitation of postural deficits in supra-tentorial stroke.
Collapse
|
16
|
Vieluf S, Temprado JJ, Berton E, Jirsa VK, Sleimen-Malkoun R. Effects of task and age on the magnitude and structure of force fluctuations: insights into underlying neuro-behavioral processes. BMC Neurosci 2015; 16:12. [PMID: 25887599 PMCID: PMC4359767 DOI: 10.1186/s12868-015-0153-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/25/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The present study aimed at characterizing the effects of increasing (relative) force level and aging on isometric force control. To achieve this objective and to infer changes in the underlying control mechanisms, measures of information transmission, as well as magnitude and time-frequency structure of behavioral variability were applied to force-time-series. RESULTS Older adults were found to be weaker, more variable, and less efficient than young participants. As a function of force level, efficiency followed an inverted-U shape in both groups, suggesting a similar organization of the force control system. The time-frequency structure of force output fluctuations was only significantly affected by task conditions. Specifically, a narrower spectral distribution with more long-range correlations and an inverted-U pattern of complexity changes were observed with increasing force level. Although not significant older participants displayed on average a less complex behavior for low and intermediate force levels. The changes in force signal's regularity presented a strong dependence on time-scales, which significantly interacted with age and condition. An inverted-U profile was only observed for the time-scale relevant to the sensorimotor control process. However, in both groups the peak was not aligned with the optimum of efficiency. CONCLUSION Our results support the view that behavioral variability, in terms of magnitude and structure, has a functional meaning and affords non-invasive markers of the adaptations of the sensorimotor control system to various constraints. The measures of efficiency and variability ought to be considered as complementary since they convey specific information on the organization of control processes. The reported weak age effect on variability and complexity measures suggests that the behavioral expression of the loss of complexity hypothesis is not as straightforward as conventionally admitted. However, group differences did not completely vanish, which suggests that age differences can be more or less apparent depending on task properties and whether difficulty is scaled in relative or absolute terms.
Collapse
Affiliation(s)
- Solveig Vieluf
- Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287, 13288, Marseille cedex 09, France.
| | - Jean-Jacques Temprado
- Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287, 13288, Marseille cedex 09, France.
| | - Eric Berton
- Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287, 13288, Marseille cedex 09, France.
| | - Viktor K Jirsa
- Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106, 13385, Marseille, France.
| | - Rita Sleimen-Malkoun
- Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287, 13288, Marseille cedex 09, France.
- Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106, 13385, Marseille, France.
| |
Collapse
|
17
|
Sleimen-Malkoun R, Temprado JJ, Hong SL. Aging induced loss of complexity and dedifferentiation: consequences for coordination dynamics within and between brain, muscular and behavioral levels. Front Aging Neurosci 2014; 6:140. [PMID: 25018731 PMCID: PMC4073624 DOI: 10.3389/fnagi.2014.00140] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/11/2014] [Indexed: 11/13/2022] Open
Abstract
Growing evidence demonstrates that aging not only leads to structural and functional alterations of individual components of the neuro-musculo-skeletal system (NMSS) but also results in a systemic re-organization of interactions within and between the different levels and functional domains. Understanding the principles that drive the dynamics of these re-organizations is an important challenge for aging research. The present Hypothesis and Theory paper is a contribution in this direction. We propose that age-related declines in brain and behavior that have been characterized in the literature as dedifferentiation and the loss of complexity (LOC) are: (i) synonymous; and (ii) integrated. We argue that a causal link between the aforementioned phenomena exists, evident in the dynamic changes occurring in the aging NMSS. Through models and methods provided by a dynamical systems approach to coordination processes in complex living systems, we: (i) formalize operational hypotheses about the general principles of changes in cross-level and cross-domain interactions during aging; and (ii) develop a theory of the aging NMSS based on the combination of the frameworks of coordination dynamics (CD), dedifferentiation, and LOC. Finally, we provide operational predictions in the study of aging at neural, muscular, and behavioral levels, which lead to testable hypotheses and an experimental agenda to explore the link between CD, LOC and dedifferentiation within and between these different levels.
Collapse
Affiliation(s)
- Rita Sleimen-Malkoun
- CNRS, Institut des Sciences du Mouvement UMR 7287, Aix-Marseille Université Marseille, France ; Inserm, Institut de Neurosciences des Systèmes UMR_S 1106, Faculté de Médecine Timone, Aix-Marseille Université Marseille, France
| | - Jean-Jacques Temprado
- CNRS, Institut des Sciences du Mouvement UMR 7287, Aix-Marseille Université Marseille, France
| | - S Lee Hong
- Ohio Musculoskeletal and Neurological Institute, Ohio University Athens, OH, USA
| |
Collapse
|
18
|
Critchley K, Kokubu M, Iemitsu M, Fujita S, Isaka T. Age-related differences in the availability of visual feedback during bimanual pinch. Eur J Appl Physiol 2014; 114:1925-32. [PMID: 24907975 DOI: 10.1007/s00421-014-2916-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 05/15/2014] [Indexed: 11/25/2022]
Abstract
PURPOSE Previous research has indicated that older adults have significantly lower accuracy in terms of force control than young adults. In addition, accuracy of force control is known to decrease in the absence of visual feedback. However, whether the effect of visual feedback on fine motor control is similar for young adults and older adults is not clear. The purpose of this study, therefore, was to examine the effect of visual feedback on bimanual pinch force control in older adults. METHODS Thirty-one undergraduate students (age 19.7 ± 0.9 years) and 31 older adults (age 65.1 ± 8.1 years) participated in this study. After measuring finger-pinch maximal voluntary force (MVF), the participants were asked to maintain 10% MVF as steadily as possible in two different conditions: with visual feedback (visual feedback condition; VF condition) and without visual feedback (no visual feedback condition; NVF condition). RESULTS We found that older adults had significantly greater targeting error and force variability than young adults in the VF condition, but not in the NVF condition. In addition, older participants exhibited a significantly greater sum of power for the 0-4 and 4-8 Hz frequency bin than young adults (p < 0.05) in the VF condition, although there was no significant difference in the NVF condition. CONCLUSIONS These results suggest that older adults do not use visual information as effectively as younger adults to reduce force control error.
Collapse
Affiliation(s)
- Kazumi Critchley
- Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | | | | | | | | |
Collapse
|
19
|
Levin O, Fujiyama H, Boisgontier MP, Swinnen SP, Summers JJ. Aging and motor inhibition: a converging perspective provided by brain stimulation and imaging approaches. Neurosci Biobehav Rev 2014; 43:100-17. [PMID: 24726575 DOI: 10.1016/j.neubiorev.2014.04.001] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/18/2014] [Accepted: 04/02/2014] [Indexed: 10/25/2022]
Abstract
The ability to inhibit actions, one of the hallmarks of human motor control, appears to decline with advancing age. Evidence for a link between changes in inhibitory functions and poor motor performance in healthy older adults has recently become available with transcranial magnetic stimulation (TMS). Overall, these studies indicate that the capacity to modulate intracortical (ICI) and interhemispheric (IHI) inhibition is preserved in high-performing older individuals. In contrast, older individuals exhibiting motor slowing and a declined ability to coordinate movement appear to show a reduced capability to modulate GABA-mediated inhibitory processes. As a decline in the integrity of the GABA-ergic inhibitory processes may emerge due to age-related loss of white and gray matter, a promising direction for future research would be to correlate individual differences in structural and/or functional integrity of principal brain networks with observed changes in inhibitory processes within cortico-cortical, interhemispheric, and/or corticospinal pathways. Finally, we underscore the possible links between reduced inhibitory functions and age-related changes in brain activation patterns.
Collapse
Affiliation(s)
- Oron Levin
- KU Leuven Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Group Biomedical Sciences, 3001 Leuven, Belgium.
| | - Hakuei Fujiyama
- KU Leuven Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Group Biomedical Sciences, 3001 Leuven, Belgium; Human Motor Control Laboratory, School of Psychology, University of Tasmania, Australia
| | - Matthieu P Boisgontier
- KU Leuven Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Group Biomedical Sciences, 3001 Leuven, Belgium
| | - Stephan P Swinnen
- KU Leuven Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Group Biomedical Sciences, 3001 Leuven, Belgium; KU Leuven, Leuven Research Institute for Neuroscience & Disease (LIND), 3001 Leuven, Belgium
| | - Jeffery J Summers
- Human Motor Control Laboratory, School of Psychology, University of Tasmania, Australia; Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 5UX United Kingdom
| |
Collapse
|
20
|
Gorniak SL, Alberts JL. Effects of aging on force coordination in bimanual task performance. Exp Brain Res 2013; 229:273-84. [PMID: 23852325 PMCID: PMC10103123 DOI: 10.1007/s00221-013-3644-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 07/01/2013] [Indexed: 11/27/2022]
Abstract
We investigated within- and between-hands grip-load force coordination in both healthy young and older adult participants during bimanual tasks involving realistic actions. Age-related changes in manual behaviors such as grip force production and safety margins were expected in older adults. Within-hand grip-load coordination was expected to decrease with aging during the performance of dynamic actions, but not static actions. The effects of task and hand dominance on task performance were also evaluated. Grip force production increased with age; however, changes in fingertip frictional properties with aging increased the risk of object slip. Indices of within-hand grip-load coordination did not alter with age, but such indices were affected by task goals. The action of connecting two independent objects, particularly with rotational action, was associated with declines in all indices of within- and between-hands force coordination, independent of age. Evidence of task-specific differences in within-hand grip-load coordination in the current data set suggests that individual hand specification emerges and persists with age in everyday bimanual prehension tasks, independent of the action role assigned to the dominant and non-dominant hands.
Collapse
Affiliation(s)
- Stacey L Gorniak
- Department of Health and Human Performance, University of Houston, Houston, TX 77204, USA.
| | | |
Collapse
|
21
|
O’Hora D, Schinkel S, Hogan MJ, Kilmartin L, Keane M, Lai R, Upton N. Age-Related Task Sensitivity of Frontal EEG Entropy During Encoding Predicts Retrieval. Brain Topogr 2013; 26:547-57. [DOI: 10.1007/s10548-013-0278-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
|
22
|
Gait variability and multiple sclerosis. Mult Scler Int 2013; 2013:645197. [PMID: 23533759 PMCID: PMC3603667 DOI: 10.1155/2013/645197] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 02/04/2013] [Indexed: 11/30/2022] Open
Abstract
Gait variability, that is, fluctuations in movement during walking, is an indicator of walking function and has been associated with various adverse outcomes such as falls. In this paper, current research concerning gait variability in persons with multiple sclerosis (MS) is discussed. It is well established that persons with MS have greater gait variability compared to age and gender matched controls without MS. The reasons for the increase in gait variability are not completely understood. Evidence indicates that disability level, assistive device use, attentional requirement, and fatigue are related to gait variability in persons with MS. Future research should address the time-evolving structure (i.e., temporal characteristics) of gait variability, the clinical importance of gait variability, and underlying mechanisms that drive gait variability in individuals with MS.
Collapse
|