Neuromodulation by means of phase-locked auditory stimulation affects key marker of excitability and connectivity during sleep

SLEEP ◽  
2021 ◽  
Author(s):  
Georgia Sousouri ◽  
Elena Krugliakova ◽  
Jelena Skorucak ◽  
Sven Leach ◽  
Sophia Snipes ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Brain Connectivity ◽  
Brain Activity ◽  
High Amplitude ◽  
Auditory Stimulation ◽  
Target Area ◽  
Experimental Conditions ◽  
Promising Tool ◽  
Underlying Mechanisms ◽  
Cortical Involvement

Abstract The propagating pattern of sleep slow waves (high-amplitude oscillations < 4.5 Hz) serves as a blueprint of cortical excitability and brain connectivity. Phase-locked auditory stimulation is a promising tool for the modulation of ongoing brain activity during sleep; however, its underlying mechanisms remain unknown. Here, eighteen healthy young adults were measured with high-density electroencephalography (hd-EEG) in three experimental conditions; one with no stimulation, one with up- and one with down-phase stimulation; ten participants were included in the analysis. We show that up-phase auditory stimulation on a right prefrontal area locally enhances cortical involvement and promotes traveling by increasing the propagating distance and duration of targeted small-amplitude waves. On the contrary, down-phase stimulation proves more efficient at perturbing large-amplitude waves and interferes with ongoing traveling by disengaging cortical regions and interrupting high synchronicity in the target area as indicated by increased traveling speed. These results point out to different underlying mechanisms mediating the effects of up- and down-phase stimulation and highlight the strength of traveling analysis as a sensitive and informative method for the study of connectivity and cortical excitability alterations.

scholarly journals The Power of Smiling: The Adult Brain Networks Underlying Learned Infant Emotionality

2019 ◽  
Vol 30 (4) ◽  
pp. 2019-2029 ◽  
Author(s):  
Eloise A Stark ◽  
Joana Cabral ◽  
Madelon M E Riem ◽  
Marinus H Van IJzendoorn ◽  
Alan Stein ◽  
...  
Keyword(s):  
Functional Neuroimaging ◽  
Brain Connectivity ◽  
Brain Activity ◽  
Brain Networks ◽  
Brain Network ◽  
Adult Brain ◽  
Significant Activity ◽  
Nulliparous Women ◽  
Emotion And Memory ◽  
Underlying Mechanisms

Abstract The perception of infant emotionality, one aspect of temperament, starts to form in infancy, yet the underlying mechanisms of how infant emotionality affects adult neural dynamics remain unclear. We used a social reward task with probabilistic visual and auditory feedback (infant laughter or crying) to train 47 nulliparous women to perceive the emotional style of six different infants. Using functional neuroimaging, we subsequently measured brain activity while participants were tested on the learned emotionality of the six infants. We characterized the elicited patterns of dynamic functional brain connectivity using Leading Eigenvector Dynamics Analysis and found significant activity in a brain network linking the orbitofrontal cortex with the amygdala and hippocampus, where the probability of occurrence significantly correlated with the valence of the learned infant emotional disposition. In other words, seeing infants with neutral face expressions after having interacted and learned their various degrees of positive and negative emotional dispositions proportionally increased the activity in a brain network previously shown to be involved in pleasure, emotion, and memory. These findings provide novel neuroimaging insights into how the perception of happy versus sad infant emotionality shapes adult brain networks.

scholarly journals EEG Fractal Analysis Reflects Brain Impairment after Stroke

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 592
Author(s):  
Maria Rubega ◽  
Emanuela Formaggio ◽  
Franco Molteni ◽  
Eleonora Guanziroli ◽  
Roberto Di Marco ◽  
...  
Keyword(s):  
Early Stage ◽  
Brain Activity ◽  
Phase 1 ◽  
Behavioral Changes ◽  
Stroke Survivors ◽  
Eeg Signals ◽  
Novel Treatments ◽  
Fractal Measures ◽  
Underlying Mechanisms ◽  
Random Fluctuations

Stroke is the commonest cause of disability. Novel treatments require an improved understanding of the underlying mechanisms of recovery. Fractal approaches have demonstrated that a single metric can describe the complexity of seemingly random fluctuations of physiological signals. We hypothesize that fractal algorithms applied to electroencephalographic (EEG) signals may track brain impairment after stroke. Sixteen stroke survivors were studied in the hyperacute (<48 h) and in the acute phase (∼1 week after stroke), and 35 stroke survivors during the early subacute phase (from 8 days to 32 days and after ∼2 months after stroke): We compared resting-state EEG fractal changes using fractal measures (i.e., Higuchi Index, Tortuosity) with 11 healthy controls. Both Higuchi index and Tortuosity values were significantly lower after a stroke throughout the acute and early subacute stage compared to healthy subjects, reflecting a brain activity which is significantly less complex. These indices may be promising metrics to track behavioral changes in the very early stage after stroke. Our findings might contribute to the neurorehabilitation quest in identifying reliable biomarkers for a better tailoring of rehabilitation pathways.

scholarly journals Recording site placement on planar silicon-based probes affects signal quality in acute neuronal recordings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richárd Fiáth ◽  
Domokos Meszéna ◽  
Zoltán Somogyvári ◽  
Mihály Boda ◽  
Péter Barthó ◽  
...  
Keyword(s):  
Single Unit ◽  
Brain Activity ◽  
Amplitude Distribution ◽  
High Amplitude ◽  
Neural Implants ◽  
Recording Site ◽  
Significant Difference ◽  
Planar Silicon ◽  
Silicon Based ◽  
Unit Yield

AbstractMultisite, silicon-based probes are widely used tools to record the electrical activity of neuronal populations. Several physical features of these devices are designed to improve their recording performance. Here, our goal was to investigate whether the position of recording sites on the silicon shank might affect the quality of the recorded neural signal in acute experiments. Neural recordings obtained with five different types of high-density, single-shank, planar silicon probes from anesthetized rats were analyzed. Wideband data were filtered to extract spiking activity, then the amplitude distribution of samples and quantitative properties of the recorded brain activity (single unit yield, spike amplitude and isolation distance) were compared between sites located at different positions of the silicon shank, focusing particularly on edge and center sites. Edge sites outperformed center sites: for all five probe types there was a significant difference in the signal power computed from the amplitude distributions, and edge sites recorded significantly more large amplitude samples both in the positive and negative range. Although the single unit yield was similar between site positions, the difference in spike amplitudes was noticeable in the range corresponding to high-amplitude spikes. Furthermore, the advantage of edge sites slightly decreased with decreasing shank width. Our results might aid the design of novel neural implants in enhancing their recording performance by identifying more efficient recording site placements.

Pathomechanisms in hepatic encephalopathy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dieter Häussinger ◽  
Markus Butz ◽  
Alfons Schnitzler ◽  
Boris Görg
Keyword(s):  
Hepatic Encephalopathy ◽  
Nitrosative Stress ◽  
Cortical Excitability ◽  
Brain Activity ◽  
System Level ◽  
Low Grade ◽  
Motor Impairments ◽  
Chronic Liver Failure ◽  
Oscillatory Brain Activity ◽  
Neuronal Functions

Abstract Hepatic encephalopathy (HE) is a frequent neuropsychiatric complication in patients with acute or chronic liver failure. Symptoms of HE in particular include disturbances of sensory and motor functions and cognition. HE is triggered by heterogeneous factors such as ammonia being a main toxin, benzodiazepines, proinflammatory cytokines and hyponatremia. HE in patients with liver cirrhosis is triggered by a low-grade cerebral edema and cerebral oxidative/nitrosative stress which bring about a number of functionally relevant alterations including posttranslational protein modifications, oxidation of RNA, gene expression changes and senescence. These alterations are suggested to impair astrocyte/neuronal functions and communication. On the system level, a global slowing of oscillatory brain activity and networks can be observed paralleling behavioral perceptual and motor impairments. Moreover, these changes are related to increased cerebral ammonia, alterations in neurometabolite and neurotransmitter concentrations and cortical excitability in HE patients.

Error-related Persistence of Motor Activity in Resting-state Networks

2018 ◽  
Vol 30 (12) ◽  
pp. 1883-1901 ◽  
Author(s):  
Nicolò F. Bernardi ◽  
Floris T. Van Vugt ◽  
Ricardo Ruy Valle-Mena ◽  
Shahabeddin Vahdat ◽  
David J. Ostry
Keyword(s):  
Motor Learning ◽  
Resting State ◽  
Brain Connectivity ◽  
Brain Activity ◽  
Brain Networks ◽  
Neural Activation ◽  
Resting State Functional Connectivity ◽  
Movement Training ◽  
Movement Error ◽  
Human Participants

The relationship between neural activation during movement training and the plastic changes that survive beyond movement execution is not well understood. Here we ask whether the changes in resting-state functional connectivity observed following motor learning overlap with the brain networks that track movement error during training. Human participants learned to trace an arched trajectory using a computer mouse in an MRI scanner. Motor performance was quantified on each trial as the maximum distance from the prescribed arc. During learning, two brain networks were observed, one showing increased activations for larger movement error, comprising the cerebellum, parietal, visual, somatosensory, and cortical motor areas, and the other being more activated for movements with lower error, comprising the ventral putamen and the OFC. After learning, changes in brain connectivity at rest were found predominantly in areas that had shown increased activation for larger error during task, specifically the cerebellum and its connections with motor, visual, and somatosensory cortex. The findings indicate that, although both errors and accurate movements are important during the active stage of motor learning, the changes in brain activity observed at rest primarily reflect networks that process errors. This suggests that error-related networks are represented in the initial stages of motor memory formation.

Functional Magnetic Resonance Imaging (FMRI)-based neurofeedback as a new treatment tool for depression

2011 ◽  
Vol 26 (S2) ◽  
pp. 937-937 ◽  
Author(s):  
D. Linden ◽  
T. Lancaster
Keyword(s):  
Repeated Measures ◽  
Rating Scale ◽  
Mood State ◽  
Control Group ◽  
Target Area ◽  
Post Intervention ◽  
Brain Areas ◽  
Promising Tool ◽  
Treatment Of Depression ◽  
New Treatment

We investigated whether depressed patients who received fMRI-based neurofeedback are able to upregulate the activity in brain areas devoted to positive emotion processing and thereby establish improvements in mood state. Eight medicated patients with major depression participated in four separate fMRI sessions, each of which consisted of an emotion localiser and three neurofeedback runs. Target areas were selected individually with a functional localiser that identified the region most responsive to positive affective images. The target areas were in uni- or bilateral prefrontal cortex, insula or amygdala. During neurofeedback runs, patients received real-time feedback about activation levels in the target area. Each patient learnt to increase target area activity over successive sessions. Depression scores on the 17-item Hamilton Depression Rating Scale improved significantly. No such improvement was seen in a non-neurofeedback control group (N = 8) that was matched for symptom severity, demographics and medication and used the same cognitive/affective strategies that were employed successfully by the neurofeedback group, but outside the scanner. This group difference in treatment effects was supported by a significant interaction between the factors time (pre/post-intervention) and group (neurofeedback/controls) on the repeated measures ANOVA (F(1,14) = 10.15, p = .007). The neurofeedback group showed increasing activity in the ventral striatum and regions involved in cognitive control as training progressed. Upregulation of brain areas responsive to positive affective cues through fMRI-neurofeedback is thus a promising tool in the treatment of depression. The novelty of the present approach consists in the combination of biological and cognitive factors in the same intervention.

scholarly journals Transcranial focused ultrasound modulates cortical and thalamic motor activity in awake sheep

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyun-Chul Kim ◽  
Wonhye Lee ◽  
Jennifer Kunes ◽  
Kyungho Yoon ◽  
Ji Eun Lee ◽  
...  
Keyword(s):  
Focused Ultrasound ◽  
Brain Activity ◽  
Response Rates ◽  
Behavioral Observation ◽  
Acoustic Stimulation ◽  
Motion Artifacts ◽  
Experimental Conditions ◽  
Low Intensity ◽  
Hind Limbs ◽  
Brain Tissue Damage

AbstractTranscranial application of pulsed low-intensity focused ultrasound (FUS) modulates the excitability of region-specific brain areas, and anesthetic confounders on brain activity warrant the evaluation of the technique in awake animals. We examined the neuromodulatory effects of FUS in unanesthetized sheep by developing a custom-fit headgear capable of reproducibly placing an acoustic focus on the unilateral motor cortex (M1) and corresponding thalamic area. The efferent responses to sonication, based on the acoustic parameters previously identified in anesthetized sheep, were measured using electromyography (EMG) from both hind limbs across three experimental conditions: on-target sonication, off-target sonication, and without sonication. Excitatory sonication yielded greater amplitude of EMG signals obtained from the hind limb contralateral to sonication than that from the ipsilateral limb. Spurious appearance of motion-related EMG signals limited the amount of analyzed data (~ 10% selection of acquired data) during excitatory sonication, and the averaged EMG response rates elicited by the M1 and thalamic stimulations were 7.5 ± 1.4% and 6.7 ± 1.5%, respectively. Suppressive sonication, while sheep walked on the treadmill, temporarily reduced the EMG amplitude from the limb contralateral to sonication. No significant change was found in the EMG amplitudes during the off-target sonication. Behavioral observation throughout the study and histological analysis showed no sign of brain tissue damage caused by the acoustic stimulation. Marginal response rates observed during excitatory sonication call for technical refinement to reduce motion artifacts during EMG acquisitions as well as acoustic aberration correction schemes to improve spatial accuracy of sonication. Yet, our results indicate that low-intensity FUS modulated the excitability of regional brain tissues reversibly and safely in awake sheep, supporting its potential in theragnostic applications.

scholarly journals Rhythmically Enhanced Music as Analgesic for Chronic Pain: A Pilot, Non-Controlled Observational Study

2021 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Richard Merrill ◽  
Mariam Taher Amin
Keyword(s):  
Chronic Pain ◽  
Brain Connectivity ◽  
Brain Activity ◽  
Mobile App ◽  
Double Blind ◽  
Pain Scores ◽  
Medication Dosage ◽  
Slow Tempo ◽  
Brainwave Entrainment

Chronic pain changes brain connectivity, brainwaves, and volume, often resulting in disability, anxiety, and depression. Opioid pain relievers impair function, with risk of addiction. Music analgesia research suggests that music for long-term analgesia includes slow tempo, pleasantness, and self-choice. Hypothesis: individuals listening to self-chosen music with embedded beats ½ h twice a day, could show brainwave entrainment (BWE) at healthy frequencies of healthy descending pain modulatory system. BWE may change brain activity, restoring organization in DPMS altered by chronic pain. Volunteers with chronic pain >1 year participated in a study of 4 weeks of listening to one half hour of music twice a day, and four weeks of non-listening, reporting pain and analgesic use bi-weekly using visual analog scale (VAS) and 0–10 numerical pain scores (NPS), medication types, and dosage. Volunteers selected from 27 half-hour pieces of music in several genres in a mobile app. Isochronic beats were embedded in the music with tempo, key, and isochronic theta frequencies proportional, to enhance the brain’s perception of rhythmic patterns and harmonics. Mean NPS showed a 26% reduction (p = 0.018). Significantly, mean medication dosage declined by over 60% (p = 0.008). Double-blind studies, larger populations are needed in future.

scholarly journals Determination of 3,4,5-Trihydroxybenzoic Acid Exploiting a Visible-Light-Driven Photoelectrochemical Platform: Application in Wine and Tea Samples

2022 ◽  
Author(s):  
Kayni Lima ◽  
Ridvan Fernandes ◽  
Clenilton dos Santos ◽  
Flavio Damos ◽  
Rita de Cássia Luz
Keyword(s):  
Light Emitting Diode ◽  
Glass Slide ◽  
Experimental Conditions ◽  
Amperometric Determination ◽  
Light Emitting ◽  
Promising Tool ◽  
Visible Light Driven ◽  
Photoelectrochemical Method ◽  
Acid Determination

The present work is based on the development and application of a photoelectrochemical method for the amperometric determination of 3,4,5-trihydroxybenzoic acid in different samples. The method is based on the use of a photoelectrochemical platform based on a glass slide coated with fluorine-doped tin oxide, which has been modified with cadmium sulfide and poly(D-glucosamine) and subjected to a light-emitting diode (LED) lamp. The photoelectrochemical platform was sensitive to the increase of the concentration of the antioxidant 3,4,5-trihydroxybenzoic acid in the solution. Under the optimized experimental conditions, the photoelectrochemical method presented a linear response for a 3,4,5-trihydroxybenzoic acid concentration ranging from 0.2 up to 500 μmol L-1. The method was applied to 3,4,5-trihydroxybenzoic acid determination in samples of wines and teas with recoveries between 95.88 and 101.72%. The results obtained suggest that the developed platform is a promising tool for quantifying the 3,4,5-trihydroxybenzoic acid.

scholarly journals The Effects and Underlying Mechanisms of Cell Therapy on Blood-Brain Barrier Integrity After Ischemic Stroke

2020 ◽  
Vol 18 (12) ◽  
pp. 1213-1226
Author(s):  
Li Gao ◽  
Zhenghong Song ◽  
Jianhua Mi ◽  
Pinpin Hou ◽  
Chong Xie ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cell Therapy ◽  
Blood Brain Barrier ◽  
Current Knowledge ◽  
Brain Barrier ◽  
Neural Cells ◽  
Promising Tool ◽  
Cell Based Therapy ◽  
Blood Brain ◽  
Underlying Mechanisms

Ischemic stroke is one of the main causes of mortality and disability worldwide. However, efficient therapeutic strategies are still lacking. Stem/progenitor cell-based therapy, with its vigorous advantages, has emerged as a promising tool for the treatment of ischemic stroke. The mechanisms involve new neural cells and neuronal circuitry formation, antioxidation, inflammation alleviation, angiogenesis, and neurogenesis promotion. In the past decades, in-depth studies have suggested that cell therapy could promote vascular stabilization and decrease blood-brain barrier (BBB) leakage after ischemic stroke. However, the effects and underlying mechanisms on BBB integrity induced by the engrafted cells in ischemic stroke have not been reviewed yet. Herein, we will update the progress in research on the effects of cell therapy on BBB integrity after ischemic stroke and review the underlying mechanisms. First, we will present an overview of BBB dysfunction under the ischemic condition and cells engraftment for ischemic treatment. Then, we will summarize and discuss the current knowledge about the effects and underlying mechanisms of cell therapy on BBB integrity after ischemic stroke. In particular, we will review the most recent studies in regard to the relationship between cell therapy and BBB in tissue plasminogen activator (t-PA)-mediated therapy and diabetic stroke.

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