scholarly journals Modulation of tactile detection threshold with rhythmic somatosensory entrainment

2019 ◽  
Author(s):  
Michel J. Wälti ◽  
Marc Bächinger ◽  
Nicole Wenderoth
Keyword(s):  
Neural Activity ◽  
Detection Threshold ◽  
Sensory Perception ◽  
Sensory Stimulation ◽  
Masking Effect ◽  
Strong Impact ◽  
Alpha Power ◽  
Brain Oscillations ◽  
Tactile Stimuli ◽  
Tactile Detection

AbstractOngoing neural activity in human somatosensory cortex has a strong impact on the detectability of weak tactile stimuli. Recent studies suggest that brain oscillations, which determine the state of excitability of a cortical area, play a crucial role in this process. Mainly two frequency bands have been reported to be involved in conscious sensory perception: alpha (8 – 12 Hz) and beta (15 – 30 Hz). In addition to correlative findings, more recent studies investigated causality by measuring the extent to which directly modulating brain oscillations affects sensory perception. While most of these studies use transcranial alternating current stimulation (tACS), rhythmic sensory stimulation has been suggested as a simple and safe alternative to entrain ongoing neural activity. However, convincing findings demonstrating the modulation of neural signals and related behavioral function are scarce.Here, we investigated whether rhythmically induced brain oscillations by means of vibrotactile stimulation (i.e. sensory entrainment) modulate tactile detection. In line with previous findings, we show in trials without sensory entrainment that preceding alpha power and phase-angles in beta oscillations predict the detection rate of a weak tactile stimulus. Further, we reveal a masking effect induced by sensory entrainment stimulation resulting in higher perception thresholds. Intriguingly, we find that the masking effect is modulated by the strength of neural entrainment resulting from 20 Hz stimulation. Our data provide evidence for the possibility to modulate sensory processing with rhythmic sensory stimulation. However, in light of the induced masking effects, the feasibility of this entrainment method to modulate human behavior remains questionable.

scholarly journals Tactile Detection in Fibromyalgia: A Systematic Review and a Meta-Analysis

2021 ◽  
Vol 2 ◽  
Author(s):  
Tania Augière ◽  
Audrey Desjardins ◽  
Emmanuelle Paquette Raynard ◽  
Clémentine Brun ◽  
Anne Marie Pinard ◽  
...  
Keyword(s):  
Systematic Review ◽  
Tactile Stimulation ◽  
Meta Analysis ◽  
Detection Threshold ◽  
Pain Syndrome ◽  
Body Representation ◽  
Future Research ◽  
Tactile Stimuli ◽  
The Central Nervous System ◽  
Tactile Detection

Fibromyalgia is a chronic pain syndrome characterized by sensorimotor deficits and distortions of body representation, that could both be caused by alterations in sensory processing. Several studies suggest a hypersensitivity to various sensory stimulations in fibromyalgia but results on detection of both noxious and non-noxious tactile stimulation, which are particularly relevant for body representation and motor control, remain conflicting. Therefore, the aim of this study is to systematically review and quantify the detection thresholds to noxious and non-noxious tactile stimuli in individuals with fibromyalgia compared to pain-free controls. A systematic review and a meta-analysis were performed in the MEDLINE, EMBASE, CINAHL, Cochrane, PsycInfo and Web of Science databases using keywords related to fibromyalgia, tactile pain detection threshold, tactile detection threshold and quantitative sensory testing. Nineteen studies were included in the review, with 12 in the meta-analysis. Despite the heterogeneity of the results, the data from both the review and from the meta-analysis suggest a trend toward hyperalgesia and no difference of sensitivity to non-noxious tactile stimuli in participants with fibromyalgia compared to healthy controls. This contradicts the hypothesis of a general increase in responsiveness of the central nervous system to noxious and non-noxious stimulations in fibromyalgia. This study shows no alteration of the sensitivity to non-noxious tactile stimulation in fibromyalgia, suggesting that an altered unimodal processing is not sufficient to explain symptoms such as sensorimotor impairments and body representation distortions. Future research should investigate whether alterations in multisensory integration could contribute to these symptoms.

scholarly journals Awake perception is associated with dedicated neuronal assemblies in cerebral cortex

2021 ◽  
Author(s):  
Anton Filipchuk ◽  
Alain Destexhe ◽  
Brice Bathellier
Keyword(s):  
Cerebral Cortex ◽  
Auditory Cortex ◽  
Neural Activity ◽  
Sensory Perception ◽  
Sensory Cortex ◽  
State Change ◽  
Ongoing Activity ◽  
Sensory Inputs ◽  
Neuronal Assemblies ◽  
Sensory Responses

AbstractNeural activity in sensory cortex combines stimulus responses and ongoing activity, but it remains unclear whether they reflect the same underlying dynamics or separate processes. Here we show that during wakefulness, the neuronal assemblies evoked by sounds in the auditory cortex and thalamus are specific to the stimulus and distinct from the assemblies observed in ongoing activity. In contrast, during anesthesia, evoked assemblies are indistinguishable from ongoing assemblies in cortex, while they remain distinct in the thalamus. A strong remapping of sensory responses accompanies this dynamical state change produced by anesthesia. Together, these results show that the awake cortex engages dedicated neuronal assemblies in response to sensory inputs, which we suggest is a network correlate of sensory perception.One-Sentence SummarySensory responses in the awake cortex engage specific neuronal assemblies that disappear under anesthesia.

Cortical oscillations to measure anti-epileptic drug activity in clinical trials

2021 ◽  
Author(s):  
Andrea Biondi ◽  
Lorenzo Rocchi ◽  
Viviana Santoro ◽  
Gregory Beatch ◽  
Pierre Rossini ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Brain Activity ◽  
Systematic Evaluation ◽  
Alpha Power ◽  
Brain Oscillations ◽  
Cortical Oscillations ◽  
Anti Epileptic Drug ◽  
Beta Power ◽  
Gamma Power

Abstract The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG), is a powerful tool to investigate changes in brain activity and excitability following the administration of antiepileptic drugs (AEDs). However, a systematic evaluation of the effect of AEDs on spontaneous and TMS-induced brain oscillations has not yet been provided. We studied the effects of lamotrigine, levetiracetam, and of a novel potassium channel opener (XEN1101) on TMS-induced and spontaneous brain oscillations in a group of healthy volunteers. Levetiracetam suppressed TMS-induced theta, alpha and beta power, whereas lamotrigine increased TMS-induced alpha power. XEN1101 decreased TMS-induced delta, theta and beta power. Resting-state EEG showed a decrease of theta band power after lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Different AEDs induce specific patterns of power changes in spontaneous and TMS-induced brain oscillations. Spontaneous and TMS-induced cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

scholarly journals Non-informative vision improves spatial tactile discrimination on the shoulder but does not influence detection sensitivity

2020 ◽  
Vol 238 (12) ◽  
pp. 2865-2875
Author(s):  
Fabrizio Leo ◽  
Sara Nataletti ◽  
Luca Brayda
Keyword(s):  
Tactile Stimulation ◽  
Detection Threshold ◽  
Receptive Fields ◽  
Judgment Task ◽  
The Body ◽  
Detection Sensitivity ◽  
Body Parts ◽  
Tactile Acuity ◽  
Tactile Stimuli ◽  
Numerosity Judgment

Abstract Vision of the body has been reported to improve tactile acuity even when vision is not informative about the actual tactile stimulation. However, it is currently unclear whether this effect is limited to body parts such as hand, forearm or foot that can be normally viewed, or it also generalizes to body locations, such as the shoulder, that are rarely before our own eyes. In this study, subjects consecutively performed a detection threshold task and a numerosity judgment task of tactile stimuli on the shoulder. Meanwhile, they watched either a real-time video showing their shoulder or simply a fixation cross as control condition. We show that non-informative vision improves tactile numerosity judgment which might involve tactile acuity, but not tactile sensitivity. Furthermore, the improvement in tactile accuracy modulated by vision seems to be due to an enhanced ability in discriminating the number of adjacent active electrodes. These results are consistent with the view that bimodal visuotactile neurons sharp tactile receptive fields in an early somatosensory map, probably via top-down modulation of lateral inhibition.

Temporal Integration and the Masking Effect of Spatiotemporal Noise

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 216-216 ◽  
Author(s):  
H T Kukkonen ◽  
J Rovamo
Keyword(s):  
Spectral Density ◽  
Exposure Duration ◽  
Temporal Integration ◽  
Detection Threshold ◽  
Critical Duration ◽  
Masking Effect ◽  
Integration Time ◽  
Detection Thresholds ◽  
Spatial Noise ◽  
Spatiotemporal Noise

In computer-generated spatiotemporal noise every stimulus frame contains a new static noise sample. The spectral density of white spatiotemporal noise is calculated by multiplying the squared rms contrast of noise by the product of the noise check area and the exposure duration of each noise check. When the exposure duration of each noise check is gradually increased, the spectral density of spatiotemporal noise increases, reaching its maximum when noise becomes static. In static spatial noise both stimulus and noise checks have the same duration. The signal-to-noise ratio is known to be constant at detection threshold. Detection thresholds should thus increase in proportion to the spectral density of spatiotemporal noise, which increases with the duration of the noise checks. We measured detection thresholds for stationary cosine gratings embedded in spatiotemporal noise. The exposure duration of the noise checks was increased from one frame duration to the total exposure duration of the stimulus grating. Noise was thus gradually transformed from spatiotemporal to static spatial noise. The contrast energy threshold increased in proportion to the spectral density of spatiotemporal noise up to a noise check duration found to be equal to the integration time for the stimulus grating without noise. After this, energy thresholds remained constant in spite of the increase in the spectral density of spatiotemporal noise. This suggests that the masking effect of spatiotemporal noise increases with the duration of noise checks up to the critical duration marking the saturation of the temporal integration of the signal.

Somatosensory Processing in the Human Inferior Prefrontal Cortex

2002 ◽  
Vol 88 (3) ◽  
pp. 1400-1406 ◽  
Author(s):  
Matthew C. Hagen ◽  
David H. Zald ◽  
Tricia A. Thornton ◽  
José V. Pardo
Keyword(s):  
Inferior Frontal Gyrus ◽  
Sensory Stimulation ◽  
Brain Regions ◽  
Somatosensory Processing ◽  
Somatosensory Stimulation ◽  
Tactile Stimuli ◽  
Somatosensory Cortices ◽  
Frontal Operculum ◽  
Frontal Activity ◽  
Ventral Area

Three inferior prefrontal regions in the monkey receive afferents from somatosensory cortices: the orbitofrontal cortex (OFC), the ventral area of the principal sulcus, and the anterior frontal operculum. To determine whether these areas show responses to tactile stimuli in humans, we examined data from an ongoing series of PET studies of somatosensory processing. Unlike previous work showing ventral frontal activity to hedonic (pleasant/unpleasant) sensory stimulation, the tactile stimuli used in these studies had a neutral hedonic valence. Our data provide evidence for at least two discrete ventral frontal brain regions responsive to somatosensory stimulation: 1) the posterior inferior frontal gyrus (IFG) and adjacent anterior frontal operculum, and 2) the OFC. The former region (posterior IFG/anterior frontal operculum) may have a more specific role in attending to tactile stimuli.

Scrutinizing integrative effects in a multi-stimuli detection task

2012 ◽  
Vol 25 (0) ◽  
pp. 100 ◽  
Author(s):  
Mario Pannunzi ◽  
Alexis Pérez-Bellido ◽  
Alexandre Pereda Baños ◽  
Joan López-Moliner ◽  
Gustavo Deco ◽  
...  
Keyword(s):  
Signal Detection Theory ◽  
Compound Stimulus ◽  
Detection Task ◽  
Sensory Stimuli ◽  
Tactile Stimuli ◽  
Auditory Detection ◽  
Theoretical Hypothesis ◽  
Multisensory Enhancement ◽  
Tactile Detection ◽  
Level Of Processing

The level of processing at which different modalities interact to either facilitate or interfere with detection has been a matter of debate for more than half a century. This question has been mainly addressed by means of statistical models (Green, 1958), or by biologically plausible models (Schnupp et al., 2005). One of the most widely accepted statistical frameworks is the signal detection theory (SDT; Green and Swets, 1966) because it provides a straightforward way to assess whether two sensory stimuli are judged independently of one another, that is when the detectability (d′) of the compound stimulus exceeds the Pythagorean sum of the d′ of the components. Here, we question this logic, and propose a different baseline to evaluate integrative effects in multi-stimuli detection tasks based on the probabilistic summation. To this aim, we show how a simple theoretical hypothesis based on probabilistic summation can explain putative multisensory enhancement in an audio-tactile detection task. In addition, we illustrate how to measure integrative effects from multiple stimuli in two experiments, one using a multisensory audio-tactile detection task (Experiment 1) and another with a unimodal double-stimulus auditory detection task (Experiment 2). Results from Experiment 1 replicate extant multisensory detection data, and also refuse the hypothesis that auditory and tactile stimuli integrated into a single percept, leading to any enhancement. In Experiment 2, we further support the probabilistic summation model using a unimodal integration detection task.

scholarly journals Changes in neural activity around the time of saccades: Separate contributions of visual and non-visual signals on MEG alpha and theta band activity

2021 ◽  
Author(s):  
David Acunzo ◽  
David Melcher
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Time Course ◽  
Brain Regions ◽  
Visual Input ◽  
Visual Signals ◽  
Perceptual Task ◽  
Alpha Power ◽  
Similar Time ◽  
Retinal Stimulation

Visual processing mainly occurs during fixation, periods separated by saccadic eye movements, necessitating a close coordination between sensory and motor systems. It has been suggested that the intention to make a saccade can modulate neural activity, including predictive changes, suppression of peri-saccadic retinal input and trans-saccadic integration. Consistent with this idea, modulations of neural activity around the time of saccades have been reported in non-human species, showing non-visually mediated, extraretinal responses in specific brain regions. In humans, however, peri-saccadic whole-brain activity has mainly been studied in the context of a perceptual task, making it difficult to disentangle activity related to the task, visual transients from retinal stimulation and non-visual (saccade-related) responses. We measured magnetoencephalography (MEG) theta (3–7 Hz) and alpha (8–12 Hz) activity during voluntary horizontal saccade execution between two fixation points. To distinguish between visually and non-visually mediated activity, participants engaged in three tasks: voluntary saccades in near-darkness, fixation with visual input shifted to simulate the saccade, and volitional saccades in total darkness. Using correlational analyses, we found that patterns of neural activity are consistent with contributions of two separate mechanisms, one related to saccades (non-visual/extraretinal) and the other linked to the processing of visual input at the beginning of the new fixation (visual/retinal). Changes in occipital alpha power and instantaneous frequency showed a similar time course in near-dark and simulated saccade conditions, suggesting an effect of visually evoked responses. In contrast, alterations in parietal-occipital theta power and phase clustering were consistent with a non-visually-driven (extraretinal) mechanism, with similar multivariate patterns for near-dark and full-darkness conditions. Some effects, such as theta phase reset and alterations in alpha power, showed separable contributions of both the saccade and visual transient, with differing time courses. This combination of visual and non-visual mechanisms may support sensorimotor integration during active vision.

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