The Relationship Between Indecisiveness and Network Integration in Scalp Resting-State EEG

Children with attention deficit hyperactivity disorder (ADHD) are characterized by a deviant pattern of brain oscillations during resting state, particularly elevated theta power and increased theta/alpha and theta/beta ratios that are related to cognitive functioning. Physical fitness has been found beneficial to cognitive performance in a wide age population. The purpose of the present study was to investigate the relationship between physical fitness and resting-state electroencephalographic (EEG) oscillations in children with ADHD. EEG was recorded during eyes-open resting for 28 children (23 boys and 5 girls, 8.66 ± 1.10 years) with ADHD, and a battery of physical fitness assessments including flexibility, muscular endurance, power, and agility tests were administered. The results indicated that ADHD children with higher power fitness exhibited a smaller theta/alpha ratio than those with lower power fitness. These findings suggest that power fitness may be associated with improved attentional self-control in children with ADHD.

Download Full-text

Lower functional hippocampal redundancy in mild cognitive impairment

Translational Psychiatry ◽

10.1038/s41398-020-01166-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Stephanie Langella ◽

◽

Muhammad Usman Sadiq ◽

Peter J. Mucha ◽

Kelly S. Giovanello ◽

...

Keyword(s):

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Cognitive Decline ◽

Resting State ◽

Memory Performance ◽

Potential Mechanism ◽

Network Efficiency ◽

Cognitively Normal ◽

Normal Individuals ◽

The Relationship

AbstractWith an increasing prevalence of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in response to an aging population, it is critical to identify and understand neuroprotective mechanisms against cognitive decline. One potential mechanism is redundancy: the existence of duplicate elements within a system that provide alternative functionality in case of failure. As the hippocampus is one of the earliest sites affected by AD pathology, we hypothesized that functional hippocampal redundancy is protective against cognitive decline. We compared hippocampal functional redundancy derived from resting-state functional MRI networks in cognitively normal older adults, with individuals with early and late MCI, as well as the relationship between redundancy and cognition. Posterior hippocampal redundancy was reduced between cognitively normal and MCI groups, plateauing across early and late MCI. Higher hippocampal redundancy was related to better memory performance only for cognitively normal individuals. Critically, functional hippocampal redundancy did not come at the expense of network efficiency. Our results provide support that hippocampal redundancy protects against cognitive decline in aging.

Download Full-text

The Governance of Public–Nonprofit Service Networks: Four Propositions

Nonprofit and Voluntary Sector Quarterly ◽

10.1177/0899764020913113 ◽

2020 ◽

Vol 49 (5) ◽

pp. 931-950 ◽

Cited By ~ 3

Author(s):

Stijn Van Puyvelde ◽

Peter Raeymaeckers

Keyword(s):

Nonprofit Organizations ◽

Network Integration ◽

Service Networks ◽

Public Agency ◽

Research And Practice ◽

Public Actor ◽

Governance Processes ◽

The Relationship

By integrating literature on governance processes with literature on network integration, we investigate the governance of mandated lead-organization public–nonprofit service networks. We argue that the relationship between the governing public actor and the participating nonprofit organizations as well as the governance processes involved are dependent upon the level of integration that is established in the network in terms of the centrality of the leading public agency and the density among the nonprofit actors. We formulate four propositions and distinguish archetypes of governance that guide further research and practice.

Download Full-text

Manufacturing network integration and culture: an institution-based view

Journal of Manufacturing Technology Management ◽

10.1108/jmtm-09-2019-0357 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Maricela C. Arellano ◽

Cristina Sancha ◽

Torbjørn Netland ◽

Cristina Gimenez Thomsen

Keyword(s):

Organizational Culture ◽

Cultural Dimensions ◽

Global Network ◽

Institutional Environments ◽

Network Integration ◽

Content Type ◽

Study Results ◽

Manufacturing Network ◽

The Relationship

PurposeIn pursuit of increased competitiveness, global manufacturers often seek tighter integration among the plants in their production networks. However, this is a challenging task because plants are dispersed across multiple institutional environments. Although the literature provides abundant evidence of how formal institutional environments affect the integration among plants, little is known about the role of the informal institutional environment – such as culture. In this study, the authors investigate the relationship between different dimensions of culture and manufacturing network integration.Design/methodology/approachThe authors combine survey data from the most recent International Manufacturing Strategy Survey with secondary data that capture cultural dimensions. They then analyze the responses from 581 assembly plants in 21 countries obtained from the survey using a multilevel regression model.FindingsThe study results show that plants located in masculine and long-term-oriented national cultures are associated with lower levels of integration with other plants. The results for the other four Hofstede dimensions of national culture were not statistically significant. At the level of organizational culture, the authors found that a collaborative plant environment positively relates to higher levels of network integration. They did not find statistically significant evidence for the relationship between cultural or geographical distance and network integration.Practical implicationsThis research provides managers with practical insights into the types and combinations of cultural environments that affect the integration of plants in a global network. This knowledge is useful for informing effective integration strategies and tactics.OriginalityThe authors provide new, empirical evidence of the relation between the informal institutional environments of a plant and its integration in a manufacturing network. Drawing on an institution-based view, they contribute to the literature on manufacturing networks by discussing and testing empirically the role of national and organizational culture in network integration.

Download Full-text

The relationship within and between the extrinsic and intrinsic systems indicated by resting state correlational patterns of sensory cortices

NeuroImage ◽

10.1016/j.neuroimage.2007.03.044 ◽

2007 ◽

Vol 36 (3) ◽

pp. 684-690 ◽

Cited By ~ 66

Author(s):

Lixia Tian ◽

Tianzi Jiang ◽

Yong Liu ◽

Chunshui Yu ◽

Kun Wang ◽

...

Keyword(s):

Resting State ◽

Sensory Cortices ◽

The Relationship

Download Full-text

Resting-state functional connectivity, cortical GABA and neuroactive steroids in peripartum and peripartum depressed women: a functional magnetic imaging and resonance study

10.1101/411405 ◽

2018 ◽

Author(s):

Kristina M. Deligiannidis ◽

Christina L. Fales ◽

Aimee R. Kroll-Desrosiers ◽

Scott A. Shaffer ◽

Vanessa Villamarin ◽

...

Keyword(s):

Functional Connectivity ◽

Resting State ◽

Neuroactive Steroids ◽

Anterior Cingulate ◽

Resonance Spectroscopy ◽

Resting State Functional Connectivity ◽

Magnetic Imaging ◽

Temporal Pole ◽

The Right ◽

The Relationship

ABSTRACTPostpartum depression (PPD) is associated with abnormalities in resting-state functional connectivity (RSFC) but the underlying neurochemistry is unclear. We hypothesized that peripartum GABAergic neuroactive steroids (NAS) are related to cortical GABA concentrations and RSFC in PPD as compared to healthy comparison women (HCW). To test this, we measured RSFC with fMRI and GABA+/Creatine (Cr) concentrations with proton magnetic resonance spectroscopy (1H MRS) in the pregenual anterior cingulate (pgACC) and occipital cortices (OCC) and quantified peripartum plasma NAS. We examined between-group differences in RSFC and the relationship between cortical GABA+/Cr concentrations with RSFC. We investigated the relationship between NAS, RSFC and cortical GABA+/Cr concentrations. Within the default mode network (DMN) an area of the dorsomedial prefrontal cortex (DMPFC) had greater connectivity with the rest of the DMN in PPD (peak voxel: MNI coordinates (2, 58, 32), p=0.002) and was correlated to depression scores (peak HAM-D17 voxel: MNI coordinates (0, 60, 34), p=0.008). pgACC GABA+/Cr correlated positively with DMPFC RSFC in a region spanning the right anterior/posterior insula and right temporal pole (r=+0.661, p=0.000). OCC GABA+/Cr correlated positively with regions spanning both amygdalae (right amygdala: r=+0.522, p=0.000; left amygdala: r=+0.651, p=0.000) as well as superior parietal areas. Plasma allopregnanolone was higher in PPD (p=0.03) and positively correlated with intra DMPFC connectivity (r=+0.548, p=0.000) but not GABA+/Cr. These results provide initial evidence that PPD is associated with altered DMN connectivity; cortical GABA+/Cr concentrations are associated with postpartum RSFC and allopregnanolone is associated with postpartum intra-DMPFC connectivity.

Download Full-text

Vascular origins of low-frequency oscillations in the cerebrospinal fluid signal in resting-state fMRI: Interpretation using photoplethysmography

10.1101/2020.10.02.323865 ◽

2020 ◽

Author(s):

Ahmadreza Attarpour ◽

James Ward ◽

J. Jean Chen

Keyword(s):

Cerebrospinal Fluid ◽

Resting State ◽

Spectral Power ◽

Low Frequency ◽

Strong Relationship ◽

Resting State Fmri ◽

M Wave ◽

Wave Range ◽

Cardiac Pulse ◽

The Relationship

AbstractSlow and rhythmic spontaneous oscillations of cerebral blood flow are well known to have diagnostic utility, notably frequencies of 0.008-0.03 Hz (B-waves) and 0.05-0.15Hz (Mayer waves or M waves). However, intracranial measurements of these oscillations have been difficult. Oscillations in the cerebrospinal fluid (CSF), which are influenced by the cardiac pulse wave, represent a possible avenue for non-invasively tracking these oscillations using resting-state functional MRI (rs-fMRI), and have been used to correct for vascular oscillations in rs-fMRI functional connectivity calculations. However, the relationship between low-frequency CSF and vascular oscillations is unclear. In this study, we investigate this relationship using fast simultaneous multi-slice rs-fMRI coupled with fingertip photoplethysmography (PPG). We not only extract B-wave and M-wave range spectral power from the PPG signal, but also derive the pulse-intensity ratio (PIR, a surrogate of slow blood-pressure oscillations), the second-derivative of the PPG (SDPPG, a surrogate of arterial stiffness) and heart-rate variability (HRV). The main findings of this study are: (1) signals in different CSF regions (ROIs) are not equivalent in their vascular contributions or in their associations with vascular and tissue rs-fMRI signals; (2) the PPG signal contains the highest signal contribution from the M-wave range, while PIR contains the highest signal contribution from the B-wave range; (3) in the low-frequency range, PIR is more strongly associated with rs-fMRI signal in the CSF than PPG itself, and than HRV and SDPPG; (4) PPG-related vascular oscillations only contribute to < 20% of the CSF signal in rs-fMRI, insufficient support for the assumption that low-frequency CSF signal fluctuations directly reflect vascular oscillations. These findings caution the use of CSF as a monolithic region for extracting physiological nuisance regressors in rs-fMRI applications. They also pave the way for using rs-fMRI in the CSF as a potential tool for tracking cerebrovascular health through, for instance the strong relationship between PIR and the CSF signal.

Download Full-text

Intrinsic sensory disinhibition contributes to intrusive re-experiencing in combat veterans

10.1101/602714 ◽

2019 ◽

Author(s):

Kevin J. Clancy ◽

Alejandro Albizu ◽

Norman B. Schmidt ◽

Wen Li

Keyword(s):

Resting State ◽

Emotional Response ◽

Combat Veterans ◽

Strong Association ◽

Cortical Inhibition ◽

Oscillatory Activity ◽

List Type ◽

Trauma Memory ◽

Novel Target ◽

The Relationship

ABSTRACTIntrusive re-experiencing of traumatic events is a hallmark symptom of posttraumatic stress disorder (PTSD). In contrast to abstract, verbal intrusions in other affective disorders, intrusive re-experiencing in PTSD is characterized by vivid sensory details as “flashbacks”. While prevailing PTSD models largely focus on dysregulated emotional processes, we hypothesize that deficient sensory inhibition in PTSD could drive overactivation of sensory representations of trauma memories, precipitating sensory-rich intrusions of trauma. In 86 combat veterans, we examined resting-state alpha (8-12 Hz) oscillatory activity (in both power and posterior→frontal connectivity), given its key role in sensory cortical inhibition, in association with intrusive re-experiencing symptoms. A subset (N = 35) of veterans further participated in an odor task (including both combat and non-combat odors) to assess olfactory trauma memory and emotional response. We observed a strong association between intrusive re-experiencing symptoms and attenuated resting-state posterior→frontal alpha connectivity, which were both correlated with olfactory trauma memory (but not emotional response). Importantly, olfactory trauma memory was further identified as a full mediator of the relationship between alpha connectivity and intrusive re-experiencing in these veterans, suggesting that deficits in intrinsic sensory inhibition can contribute to intrusive re-experiencing of trauma via heightened trauma memory. Therefore, by permitting unfiltered sensory cues to enter information processing and spontaneously activating sensory representations of trauma, impaired sensory inhibition can constitute a sensory mechanism of intrusive re-experiencing in PTSD.HIGHLIGHTSAlpha oscillations (indexing sensory inhibition) measured in 86 combat veteransRe-experiencing symptom severity was associated with attenuated alpha connectivityTrauma memory for, not emotional response to, odors mediated this relationshipTrauma memories may arise via disinhibited activation of sensory representationsSensory systems may be novel target for intrusive re-experiencing symptom treatment

Download Full-text

Analysis of a Signal Transmission in a Pair of Izhikevich Coupled Neurons

Biophysical Reviews and Letters ◽

10.1142/s1793048020400019 ◽

2020 ◽

Vol 15 (04) ◽

pp. 195-206

Author(s):

David. H. Margarit ◽

Marcela V. Reale ◽

Ariel F. Scagliotti

Keyword(s):

White Noise ◽

Resting State ◽

Signal Transmission ◽

Electrical Potential ◽

Signal Amplitude ◽

Receptor Neuron ◽

Neuron Models ◽

The Relationship ◽

The Brain ◽

Izhikevich Model

Individual neuron models give a comprehensive explanation of the behavior of the electrical potential of cell membranes. These models were and are a source of constant analysis to understand the functioning of, mainly, the complexity of the brain. In this work, using the Izhikevich model, we propose, analyze and characterize the transmission of a signal between two neurons unidirectionally coupled. Two possible states were characterized (sub-threshold and over-threshold) depending on the values of the signal amplitude, as well also the relationship between the transmitted and received signal taking into account the coupling. Furthermore, the activation of the emitting neuron (its transition from a resting state to spiking state) and the transmission to the receptor neuron were analyzed by adding white noise to the system.

Download Full-text

Sex differences in the relationship between cardiorespiratory fitness and brain function in older adulthood

Journal of Applied Physiology ◽

10.1152/japplphysiol.01046.2018 ◽

2019 ◽

Vol 126 (4) ◽

pp. 1032-1041 ◽

Cited By ~ 3

Author(s):

Christina J. Dimech ◽

John A. E. Anderson ◽

Amber W. Lockrow ◽

R. Nathan Spreng ◽

Gary R. Turner

Keyword(s):

Older Adults ◽

Sex Differences ◽

Functional Connectivity ◽

Cardiorespiratory Fitness ◽

Resting State ◽

Brain Function ◽

Network Integration ◽

Resting State Functional Connectivity ◽

Older Adulthood ◽

Fitness Level

We investigated sex differences in the association between a measure of physical health, cardiorespiratory fitness (CRF), and brain function using resting-state functional connectivity fMRI. We examined these sex differences in the default, frontoparietal control, and cingulo-opercular networks, assemblies of functionally connected brain regions known to be impacted by both age and fitness level. Healthy older adults ( n = 49; 29 women) were scanned to obtain measures of intrinsic connectivity within and across these 3 networks. We calculated global efficiency (a measure of network integration) and local efficiency (a measure of network specialization) using graph theoretical methods. Across all three networks combined, local efficiency was positively associated with CRF, and this was more robust in male versus female older adults. Furthermore, global efficiency was negatively associated with CRF, but only in males. Our findings suggest that in older adults, associations between brain network integrity and physical health are sex-dependent. These results underscore the importance of considering sex differences when examining associations between fitness and brain function in older adulthood. NEW & NOTEWORTHY We examined the association between cardiorespiratory fitness and resting state functional connectivity in several brain networks known to be impacted by age and fitness level. We found significant associations between fitness and measures of network integration and network specialization, but in a sex-dependent manner, highlighting the interplay between sex differences, fitness, and aging brain health. Our findings underscore the importance of considering sex differences when examining associations between fitness and brain function in older adulthood.

Download Full-text