Multiple mechanisms link prestimulus neural oscillations to sensory responses

eLife, Journal Year: 2019, Volume and Issue: 8

Published: June 12, 2019

Spontaneous fluctuations of neural activity may explain why sensory responses vary across repeated presentations the same physical stimulus. To test this hypothesis, we recorded electroencephalography in humans during stimulation with identical visual stimuli and analyzed how prestimulus oscillations modulate different stages processing reflected by distinct components event-related potential (ERP). We found that strong alpha- beta-band power resulted a suppression early ERP (C1 N150) an amplification late (after 0.4 s), even after controlling for 1/f aperiodic signal sleepiness. Whereas functional inhibition underlies reduction responses, modulation non-zero-mean (baseline shift) accounted responses. Distinguishing between these two mechanisms is crucial understanding internal brain states incoming information.

Language: Английский

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Intrinsic excitation-inhibition imbalance affects medial prefrontal cortex differently in autistic men versus women

eLife, Journal Year: 2020, Volume and Issue: 9

Published: Aug. 4, 2020

Excitation-inhibition (E:I) imbalance is theorized as an important pathophysiological mechanism in autism. Autism affects males more frequently than females and sex-related mechanisms (e.g., X-linked genes, androgen hormones) can influence E:I balance. This suggests that may affect autism differently versus females. With a combination of in-silico modeling in-vivo chemogenetic manipulations mice, we first show time-series metric estimated from fMRI BOLD signal, the Hurst exponent (H), be index for underlying change synaptic ratio. In find H reduced, indicating increased excitation, medial prefrontal cortex (MPFC) autistic but not Increasingly intact MPFC also associated with heightened ability to behaviorally camouflage social-communicative difficulties, only work ratio differently.

Language: Английский

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Memantine Effects on Electroencephalographic Measures of Putative Excitatory/Inhibitory Balance in Schizophrenia

Biological Psychiatry Cognitive Neuroscience and Neuroimaging, Journal Year: 2020, Volume and Issue: 5(6), P. 562 - 568

Published: Feb. 22, 2020

Language: Английский

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The frequency gradient of human resting-state brain oscillations follows cortical hierarchies

eLife, Journal Year: 2020, Volume and Issue: 9

Published: Aug. 21, 2020

The human cortex is characterized by local morphological features such as cortical thickness, myelin content, and gene expression that change along the posterior-anterior axis. We investigated if some of these structural gradients are associated with a similar gradient in prominent feature brain activity - namely frequency oscillations. In resting-state MEG recordings from healthy participants (N = 187) using mixed effect models, we found dominant peak area decreases significantly axis following global hierarchy early sensory to higher order areas. This spatial was anticorrelated representing proxy hierarchical level. result indicates changes systematically globally establishes new structure-function relationship pertaining oscillations core organization may underlie specialization brain.

Language: Английский

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Single-trial characterization of neural rhythms: Potential and challenges

NeuroImage, Journal Year: 2019, Volume and Issue: 206, P. 116331 - 116331

Published: Nov. 8, 2019

The average power of rhythmic neural responses as captured by MEG/EEG/LFP recordings is a prevalent index human brain function. Increasing evidence questions the utility trial-/group averaged estimates however, seemingly sustained activity patterns may be brought about time-varying transient signals in each single trial. Hence, it crucial to accurately describe duration and arrhythmic on trial-level. However, less clear how well this can achieved empirical recordings. Here, we extend an existing rhythm detection algorithm (extended Better OSCillation detection: "eBOSC"; cf. Whitten et al., 2011) systematically investigate boundary conditions for estimating rhythms at single-trial level. Using simulations resting task-based EEG from micro-longitudinal assessment, show that alpha successfully trials with high specificity, but quality varies greatly between subjects. Despite those signal-to-noise-based limitations, highlight potential multiple proof-of-concept examples, discuss implications analyses electrophysiological applied example working memory retention, indicated load-related increases frontal theta posterior rhythms, addition frequency decrease was observed exclusively through amplification amplitudes.

Language: Английский

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Surface color and predictability determine contextual modulation of V1 firing and gamma oscillations

eLife, Journal Year: 2019, Volume and Issue: 8

Published: Feb. 4, 2019

The integration of direct bottom-up inputs with contextual information is a core feature neocortical circuits. In area V1, neurons may reduce their firing rates when receptive field input can be predicted by spatial context. Gamma-synchronized (30–80 Hz) provide complementary signal to rates, reflecting stronger synchronization between neuronal populations receiving mutually predictable inputs. We show that large uniform surfaces, which have high predictability, strongly suppressed yet induced prominent gamma in macaque particularly they were colored. Yet, chromatic mismatches center and surround, breaking reduced while increasing rates. Differences responses different colors, including strong gamma-responses red, arose from stimulus adaptation full-screen background, suggesting differences M- L-cone signaling pathways. Thus, synchrony signaled whether RF context, increased stimuli unpredicted

Language: Английский

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Spectral and Entropic Features Are Altered by Age in the Electroencephalogram in Patients under Sevoflurane Anesthesia

Anesthesiology, Journal Year: 2020, Volume and Issue: 132(5), P. 1003 - 1016

Published: Feb. 26, 2020

Abstract Background Preexisting factors such as age and cognitive performance can influence the electroencephalogram (EEG) during general anesthesia. Specifically, spectral EEG power is lower in elderly, compared to younger, subjects. Here, authors investigate age-related changes architecture patients undergoing anesthesia through a detailed examination of entropic measures. Methods The retrospectively studied 180 frontal recordings from anesthesia, induced with propofol/fentanyl maintained by sevoflurane at Waikato Hospital Hamilton, New Zealand. calculated density normalized density, measures approximate permutation entropy, well beta ratio entropy exemplary parameters used current monitoring systems segments obtained before onset surgery (i.e., no noxious stimulation). Results oldest quartile had significantly 1/f characteristics (P < 0.001; area under receiver operating curve, 0.84 [0.76 0.92]), indicative more uniform distribution power. Analysis revealed significant impact on relative alpha = 0.693; 0.52 [0.41 0.63]) but weak effect 0.041; 0.62 [0.52 0.73]). Using parameters, found change toward irregular unpredictable (permutation entropy: P 0.001, 0.81 [0.71 0.90]; 0.76 [0.66 0.85]). With could also detect an age-induced alpha-band activity 0.002; 0.69 [0.60 78]). Conclusions Like sleep literature, features revealing shift faster, irregular, oscillatory composition older patients. Age-related neurophysiological may underlie these findings however contribution filtering properties or signal noise must be considered. Regardless, most technology guide anesthetic management focus features, improvements devices might involve integration raw EEG. Editor’s Perspective What We Already Know about This Topic Article Tells Us That Is

Language: Английский

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Sensorimotor Peak Alpha Frequency Is a Reliable Biomarker of Prolonged Pain Sensitivity

Cerebral Cortex, Journal Year: 2020, Volume and Issue: 30(12), P. 6069 - 6082

Published: April 24, 2020

Previous research has observed that the speed of alpha band oscillations (8-12 Hz range) recorded during resting electroencephalography is slowed in chronic pain patients. While this slowing may reflect pathological changes occur chronification pain, an alternative explanation healthy individuals with slower are more sensitive to prolonged and by extension, susceptible developing pain. To test hypothesis, we examined relationship between pain-free, oscillation their sensitivity two models Phasic Heat Pain Capsaicin Pain, at visits separated 8 weeks on average (n = 61 Visit 1, n 46 2). We individual's pain-free was negatively correlated both reliable across short (minutes) long (weeks) timescales. Furthermore, can successfully identify most individuals, which validated data from a separate, independent study. These results suggest biomarker potential for prospectively identifying clinic.

Language: Английский

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Linked Sources of Neural Noise Contribute to Age-related Cognitive Decline

Journal of Cognitive Neuroscience, Journal Year: 2020, Volume and Issue: 32(9), P. 1813 - 1822

Published: May 19, 2020

Healthy aging is associated with a multitude of structural changes in the brain. These physical age-related are accompanied by increased variability neural activity all kinds, and this variability, collectively referred to as "neural noise," argued contribute cognitive decline. In study, we examine relationship between two particular types noise aging. We recorded scalp EEG from younger (20-30 years old) older (60-70 adults performing spatial visual discrimination task. First, used 1/f-like exponent power spectrum, putative marker noise, assess baseline shifts toward noisier state Next, examined decreases trial-by-trial consistency stimulus processing. Finally, what extent these markers related, hypothesizing that greater would increase stimulus-evoked responses. found cortical was higher adults, adults' oscillatory alpha (8-12 Hz) phase responses targets also lower than adults. Crucially, highest levels had least consistent responses, whereas more achieved better behavioral performance. results establish link tonic stimulus-associated Moreover, they suggest increases might diminish sensory processing and, result, subsequent

Language: Английский

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Functionally Distinct Gamma Range Activity Revealed by Stimulus Tuning in Human Visual Cortex

Current Biology, Journal Year: 2019, Volume and Issue: 29(20), P. 3345 - 3358.e7

Published: Oct. 1, 2019

Highlights•Temporal, spectral, and functional properties dissociate narrow broadband gamma•Narrowband gamma is tuned to visual gratings long-wavelength hues (red/orange)•Narrowband responses natural images reflect low-level stimulus tuning•Stimulus dependencies limit the role of narrowband oscillationsSummaryNeocortical activity has long been hypothesized as a mechanism for synchronizing brain regions support perception cognition more broadly. Although early studies focused on oscillations (∼20–60 Hz), recent work emphasized "high-gamma" response (∼70–150+ Hz). These are often conceptually or analytically treated synonymous markers activity. Using high-density intracranial recordings from human cortex, we challenge this view by showing distinct temporal, gamma. Across four experiments, was strongly selective colors, displaying delayed onset, sustained temporal profile, contrast-dependent peak frequency. In addition, induced lacked phase consistency across repetitions displayed highly focal inter-site synchronization. contrast, consistently observed all presented stimuli, rapid transient invariant spectral properties. We exploited tuning highlight dissociation these signals, reconciling prior inconsistencies species stimuli regarding ubiquity during vision. The occurrence oscillations, unlike high gamma, appears contingent specific structural chromatic attributes intersecting with receptive field. Together, findings have important implications study, analysis, interpretation neocortical gamma-range activity.Graphical abstract

Language: Английский

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