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•Periodic and aperiodic EEG parameters associated with distinct resting-state networks.•Increases in aperiodic power associated with an auditory-salience-cerebellar network.•Decreases in aperiodic power associated with prefrontal regions.•Global neural excitability may reflect stimulus processing or arousal attributable to the uniqueness of the resting-state MR-scanner environment. The hallmark of resting EEG spectra are distinct rhythms emerging from a broadband, aperiodic background. This aperiodic neural signature accounts for most of total EEG power, although its significance and relation to functional neuroanatomy remains obscure. We hypothesized that aperiodic EEG reflects a significant metabolic expenditure and therefore might be associated with the default mode network while at rest. During eyes-open, resting-state recordings of simultaneous EEG-fMRI, we find that aperiodic and periodic components of EEG power are only minimally associated with activity in the default mode network. However, a whole-brain analysis identifies increases in aperiodic power correlated with hemodynamic activity in an auditory-salience-cerebellar network, and decreases in aperiodic power are correlated with hemodynamic activity in prefrontal regions. Desynchronization in residual alpha and beta power is associated with visual and sensorimotor hemodynamic activity, respectively. These findings suggest that resting-state EEG signals acquired in an fMRI scanner reflect a balance of top-down and bottom-up stimulus processing, even in the absence of an explicit task.

Abstract Functional magnetic resonance imaging (fMRI) scanners are unavoidably loud and uncomfortable experimental tools that are necessary for schizophrenia (SZ) neuroscience research. The validity of fMRI paradigms might be undermined by well-known sensory processing abnormalities in SZ that could exert distinct effects on neural activity in the presence of scanner background sound. Given the ubiquity of resting-state fMRI (rs-fMRI) paradigms in SZ research, elucidating the relationship between neural, hemodynamic, and sensory processing deficits during scanning is necessary to refine the construct validity of the MR neuroimaging environment. We recorded simultaneous electroencephalography (EEG)-fMRI at rest in people with SZ (n = 57) and healthy control participants without a psychiatric diagnosis (n = 46) and identified gamma EEG activity in the same frequency range as the background sounds emitted from our scanner during a resting-state sequence. In participants with SZ, gamma coupling to the hemodynamic signal was reduced in bilateral auditory regions of the superior temporal gyri. Impaired gamma-hemodynamic coupling was associated with sensory gating deficits and worse symptom severity. Fundamental sensory-neural processing deficits in SZ are present at rest when considering scanner background sound as a “stimulus.” This finding may impact the interpretation of rs-fMRI activity in studies of people with SZ. Future neuroimaging research in SZ might consider background sound as a confounding variable, potentially related to fluctuations in neural excitability and arousal.

Our goal is to understand the neural basis of functional impairment in aging and Alzheimer's disease (AD) to be able to characterize clinically significant decline and assess therapeutic efficacy. We used frequency-tagged ERPs to word and motion stimuli to study the effects of stimulus conditions and selective attention. ERPs to word or motion increase when a task-irrelevant 2nd stimulus is added, but decrease when the task is moved to that 2nd stimulus. Spectral analyses show task effects on response power without 2nd stimulus effects. However, phase coherence shows both 2nd stimulus and task effects. Thus, power and coherence are dissociably modulated by stimulus and task effects. Task-dependent phase coherence successively declines in aging and AD. In contrast, task-dependent spectral power increases in aging, only to decrease in AD. We hypothesize that age-related declines in signal coherence, associated with increased power generation, stresses neurons and contributes to the loss of response power and the development of functional impairment in AD.

Psychiatry residency programs with robust research training can prepare physician-scientists to make contributions that advance the mental health field. Our psychiatry residency developed a chief resident for research position to help provide mentorship, community building, and advising around scholarly activities for residents. We present the process of implementing this new position in our residency to offer a model for engaging psychiatry residents in research.

Flat-water kayaking is one of the best-known competitive canoeing disciplines in Australia and across the European countries. From a stationary start, paddlers are required to paddle their kayaks with maximal effort along the length of the competing distance. The ultimate criterion of kayak performance is the time taken to paddle a designated competition distance. In flat-water racing, events are contested over 500 and 1000 metres. To approximate the ultimate criterion over these distances, the velocity of the kayak should be measured. Furthermore, other factors that affect performance, such as force, power, technique and aerobic fitness, would all provide a valuable insight to the success of the kayak paddler. Specific research performed examining the physiological demands on kayak paddlers demonstrate high levels of both aerobic power and anaerobic capacity. It is the purpose if this review to present the published physiological data relating to men's and women's kayaking. With a number of recent publications, a need for an updated review is necessary. The present review summarises recent data on anthropometrics, physiological characteristics of successful and unsuccessful kayak athletes and methods of physiological testing. Due to the fact that more data have been reported for male competitors than for their female counterparts, the demands of kayaking on male athletes will be the main focus for this review. The review also suggests areas for future research into flatwater kayaking performance. Understanding the physiological requirements of kayaking can assist coaches and athletes in a number of ways. During competition or training, such information is helpful in the selection of appropriate protocols and metabolic indices to monitor an athlete's performance improvements and assess an athlete's suitability for a particular race distance. Furthermore, it may aid the coach in the development of more specific training programs for their athletes. Key pointsFlat water kayaking is characterised by exceptional demands on upper body performance.When examining the oxygen consumption, it is notable that although a high value is attainable, they are not quite as high as other sporting events such as road cycling, rowing or running where lower body is dominant.Elite kayakers demonstrate superior aerobic and anaerobic quantities and have reported maximal oxygen consumptions of around 58 ml·kg(-1)·min(-1) (4.7 L·min(-1)) and lactate values of around 12 mM during laboratory and on water testing.

ABSTRACT The hallmark of resting EEG spectra are distinct rhythms emerging from a broadband, aperiodic background. This aperiodic neural signature accounts for most of total EEG power, although its significance and relation to functional neuroanatomy remains obscure. We hypothesized that aperiodic EEG reflects a significant metabolic expenditure and therefore might be associated with the default mode network while at rest. During eyes-open, resting-state recordings of simultaneous EEG-fMRI, we find that aperiodic and periodic components of EEG power are only minimally associated with activity in the default mode network. However, a whole-brain analysis identifies increases in aperiodic power correlated with hemodynamic activity in an auditory-salience-cerebellar network, and decreases in aperiodic power are correlated with hemodynamic activity in prefrontal regions. Desynchronization in residual alpha and beta power is associated with visual and sensorimotor hemodynamic activity, respectively. These findings suggest that resting-state EEG signals acquired in an fMRI scanner reflect a balance of top-down and bottom-up stimulus processing, even in the absence of an explicit task. HIGHLIGHTS * Periodic and aperiodic EEG parameters associated with distinct resting-state networks * Increases in aperiodic power associated with an auditory-salience-cerebellar network * Decreases in aperiodic power associated with prefrontal regions * Global neural excitability may reflect stimulus processing or arousal attributable to the uniqueness of the resting-state MR-scanner environment Competing Interest Statement The authors have declared no competing interest. Footnotes * Email addresses: Michael.Jacob{at}ucsf.edu Brian.Roach{at}ncire.org kaiasargent7{at}gmail.com Daniel.Mathalon{at}ucsf.edu Judith.Ford{at}ucsf.edu

Delta Air Lines, Inc., forms alliances with other airlines to expand the network of markets it can serve through a process known as codesharing . Codesharing allows an airline to place its marketing code on an alliance partner's flights. A carrier can then sell these flights, although an alliance partner operates them. Alliances can improve the revenue streams of their members; however, the amount of revenue increase depends significantly on which flights are chosen for codeshare. As alliances have evolved, the number of flights being codeshared has grown, and the rules that airlines must follow have become more complex. The authors have built a codeshare flight-profitability system that automates the codeshare flight-selection process. The system chooses a set of codeshare flights that maximizes total system revenue for Delta while satisfying the rules that the alliance, the government, and the airlines' unions have set. The initial impact of this decision-making tool appears to be promising. Codeshared decisions, which Delta previously made without the benefit of optimization technologies, took one to two days to complete. The new system for choosing codeshared flights seeks to increase Delta's operating revenue by up to $50 M per year while reducing the planning cycle to several hours.

Spectral analysis of electroencephalographic (EEG) data simplifies the characterization of periodic band parameters but can obscure underlying dynamics. By contrast, reconstruction of neural activity in state-space preserves geometric complexity in the form of a multidimensional, global attractor. Here we combine these perspectives, inferring complexity and shared dynamics from eigen-time-delay embedding of periodic and aperiodic spectral parameters to yield unique dynamical attractors for each EEG parameter. We find that resting-state alpha and aperiodic attractors show low geometric complexity and shared dynamics with all other frequency bands, what we refer to as geometric cross-parameter coupling. Further, the geometric signatures of alpha and aperiodic attractors dominate spectral dynamics, identifying a geometric core of brain activity. Non-core attractors demonstrate higher complexity but retain traces of this low-dimensional signal, supporting a hypothesis that frequency specific information differentiates out of an integrative, dynamic core. Older adults show lower geometric complexity but greater geometric coupling, resulting from dedifferentiation of gamma band activity. The form and content of resting-state thoughts were further associated with the complexity of core dynamics. Thus, the hallmarks of resting-state EEG in the frequency domain, the alpha peak and the aperiodic backbone, reflect a dynamic, geometric core of resting-state brain activity. This evidence for a geometric core in EEG complements evidence for a regionally defined dynamic core from fMRI-based neuroimaging, further supporting the utility of geometric approaches to the analysis of neural data.