Alpha oscillations are involved in localizing touch on hand-held tools

The sense of touch is not restricted to the body but can also extend to external objects. When we use a hand-held tool to contact an object, we feel the touch on the tool and not in the hand holding the tool. The ability to perceive touch on a tool actually extends along its entire surface, allowing the user to accurately localize where it is touched similarly as they would on their body. While the neural mechanisms underlying the ability to localize touch on the body have been largely investigated, those allowing to localize touch on a tool are still unknown. We aimed to fill this gap by recording the EEG signal of participants while they localized tactile stimuli on a hand-held rod. We focused on oscillatory activity in the alpha (7-14 Hz) and beta (15-30 Hz) range, as they have been previously linked to distinct spatial codes used to localize touch on the body. Beta activity reflects the mapping of touch in skin-based coordinates, whereas alpha activity reflects the mapping of touch in external space. We found that alpha activity was solely modulated by the location of tactile stimuli applied on a hand-held rod. Source reconstruction suggested that this alpha power modulation was localized in a network of fronto-parietal regions previously implicated in higher-order tactile and spatial processing. These findings are the first to implicate alpha oscillations in tool-extended sensing and suggest an important role for processing touch in external space when localizing touch on a tool.

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Alpha Oscillations Correlate with the Successful Inhibition of Unattended Stimuli

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2010.21557 ◽

2011 ◽

Vol 23 (9) ◽

pp. 2494-2502 ◽

Cited By ~ 229

Author(s):

Barbara F. Händel ◽

Thomas Haarmeier ◽

Ole Jensen

Keyword(s):

Visual System ◽

Alpha Activity ◽

Coherent Motion ◽

Motion Processing ◽

Alpha Power ◽

Motion Direction ◽

Alpha Oscillations ◽

Visual Hemifield ◽

Left And Right ◽

Visual Hemifields

Because the human visual system is continually being bombarded with inputs, it is necessary to have effective mechanisms for filtering out irrelevant information. This is partly achieved by the allocation of attention, allowing the visual system to process relevant input while blocking out irrelevant input. What is the physiological substrate of attentional allocation? It has been proposed that alpha activity reflects functional inhibition. Here we asked if inhibition by alpha oscillations has behavioral consequences for suppressing the perception of unattended input. To this end, we investigated the influence of alpha activity on motion processing in two attentional conditions using magneto-encephalography. The visual stimuli used consisted of two random-dot kinematograms presented simultaneously to the left and right visual hemifields. Subjects were cued to covertly attend the left or right kinematogram. After 1.5 sec, a second cue tested whether subjects could report the direction of coherent motion in the attended (80%) or unattended hemifield (20%). Occipital alpha power was higher contralateral to the unattended side than to the attended side, thus suggesting inhibition of the unattended hemifield. Our key finding is that this alpha lateralization in the 20% invalidly cued trials did correlate with the perception of motion direction: Subjects with pronounced alpha lateralization were worse at detecting motion direction in the unattended hemifield. In contrast, lateralization did not correlate with visual discrimination in the attended visual hemifield. Our findings emphasize the suppressive nature of alpha oscillations and suggest that processing of inputs outside the field of attention is weakened by means of increased alpha activity.

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Prefrontal cortex modulates posterior alpha oscillations during top-down guided visual perception

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1705965114 ◽

2017 ◽

Vol 114 (35) ◽

pp. 9457-9462 ◽

Cited By ~ 36

Author(s):

Randolph F. Helfrich ◽

Melody Huang ◽

Guy Wilson ◽

Robert T. Knight

Keyword(s):

Visual Perception ◽

Alpha Activity ◽

Alpha Power ◽

Top Down ◽

Visual Stream ◽

Alpha Oscillations ◽

Fine Grained ◽

Oscillatory Dynamics ◽

Delta Activity ◽

And Behavior

Conscious visual perception is proposed to arise from the selective synchronization of functionally specialized but widely distributed cortical areas. It has been suggested that different frequency bands index distinct canonical computations. Here, we probed visual perception on a fine-grained temporal scale to study the oscillatory dynamics supporting prefrontal-dependent sensory processing. We tested whether a predictive context that was embedded in a rapid visual stream modulated the perception of a subsequent near-threshold target. The rapid stream was presented either rhythmically at 10 Hz, to entrain parietooccipital alpha oscillations, or arrhythmically. We identified a 2- to 4-Hz delta signature that modulated posterior alpha activity and behavior during predictive trials. Importantly, delta-mediated top-down control diminished the behavioral effects of bottom-up alpha entrainment. Simultaneous source-reconstructed EEG and cross-frequency directionality analyses revealed that this delta activity originated from prefrontal areas and modulated posterior alpha power. Taken together, this study presents converging behavioral and electrophysiological evidence for frontal delta-mediated top-down control of posterior alpha activity, selectively facilitating visual perception.

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The phase of prestimulus alpha oscillations affects tactile perception

Journal of Neurophysiology ◽

10.1152/jn.00125.2013 ◽

2014 ◽

Vol 111 (6) ◽

pp. 1300-1307 ◽

Cited By ~ 57

Author(s):

Lei Ai ◽

Tony Ro

Keyword(s):

Brain Activity ◽

Brain Regions ◽

Stimulus Onset ◽

Tactile Perception ◽

Alpha Power ◽

Perceptual Awareness ◽

Alpha Oscillations ◽

Left Hand ◽

Tactile Stimuli ◽

Significant Difference

Previous studies have shown that neural oscillations in the 8- to 12-Hz range influence sensory perception. In the current study, we examined whether both the power and phase of these mu/alpha oscillations predict successful conscious tactile perception. Near-threshold tactile stimuli were applied to the left hand while electroencephalographic (EEG) activity was recorded over the contralateral right somatosensory cortex. We found a significant inverted U-shaped relationship between prestimulus mu/alpha power and detection rate, suggesting that there is an intermediate level of alpha power that is optimal for tactile perception. We also found a significant difference in phase angle concentration at stimulus onset that predicted whether the upcoming tactile stimulus was perceived or missed. As has been shown in the visual system, these findings suggest that these mu/alpha oscillations measured over somatosensory areas exert a strong inhibitory control on tactile perception and that pulsed inhibition by these oscillations shapes the state of brain activity necessary for conscious perception. They further suggest that these common phasic processing mechanisms across different sensory modalities and brain regions may reflect a common underlying encoding principle in perceptual processing that leads to momentary windows of perceptual awareness.

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Linking alpha oscillations, attention and inhibitory control in adult ADHD with EEG neurofeedback

10.1101/689398 ◽

2019 ◽

Cited By ~ 1

Author(s):

Marie-Pierre Deiber ◽

Roland Hasler ◽

Julien Colin ◽

Alexandre Dayer ◽

Jean-Michel Aubry ◽

...

Keyword(s):

Inhibitory Control ◽

Resting State ◽

Adult Adhd ◽

Alpha Rhythm ◽

Oscillatory Activity ◽

Supporting Evidence ◽

Alpha Power ◽

Adhd Group ◽

List Type ◽

Alpha Oscillations

AbstractAbnormal patterns of electrical oscillatory activity have been repeatedly described in adult ADHD. In particular, the alpha rhythm (8-12 Hz), known to be modulated during attention, has previously been considered as candidate biomarker for ADHD. In the present study, we asked adult ADHD patients to self-regulate their own alpha rhythm using neurofeedback (NFB), in order to examine the modulation of alpha oscillations on attentional performance and brain plasticity. Twenty-five adult ADHD patients and 22 healthy controls underwent a 64-channel EEG-recording at resting-state and during a Go/NoGo task, before and after a 30 min-NFB session designed to reduce (desynchronize) the power of the alpha rhythm. Alpha power was compared across conditions and groups, and the effects of NFB were statistically assessed by comparing behavioral and EEG measures pre-to-post NFB. Firstly, we found that relative alpha power was attenuated in our ADHD cohort compared to control subjects at baseline and across experimental conditions, suggesting a signature of cortical hyper-activation. Both groups demonstrated a significant and targeted reduction of alpha power during NFB. Interestingly, we observed a post-NFB increase in resting-state alpha (i.e. rebound) in the ADHD group, which restored alpha power towards levels of the normal population. Importantly, the degree of post-NFB alpha normalisation during the Go/NoGo task correlated with individual improvements in motor inhibition (i.e. reduced commission errors and slower reaction times in NoGo trials) only in the ADHD group. Overall, our findings offer novel supporting evidence implicating alpha oscillations in inhibitory control, as well as their potential role in the homeostatic regulation of cortical excitatory/inhibitory balance.HighlightsResting alpha power is reduced in adult ADHD suggesting cortical hyper-activationAdult ADHD patients successfully reduce alpha power during neurofeedbackA post-neurofeedback rebound normalizes alpha power in adult ADHDAlpha power rebound correlates with improvement of inhibitory control in adult ADHD

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Methylphenidate normalizes aberrant beta oscillations and reduces alpha power during retention in children with ADHD

10.1101/2020.03.13.990929 ◽

2020 ◽

Author(s):

C. Mazzetti ◽

N. ter Huurne ◽

J.K. Buitelaar ◽

O. Jensen

Keyword(s):

Working Memory ◽

Stimulant Medication ◽

Memory Load ◽

Oscillatory Activity ◽

Control Group ◽

Alpha Power ◽

Adhd Group ◽

Brain Oscillations ◽

Children With Adhd ◽

Alpha 7

AbstractAttention Deficit-Hyperactivity Disorder (ADHD) has been intensively studied in neurodevelopmental research, with the aim to identify the neural substrates of the disorder. Prior studies have established that brain oscillations in specific frequency ranges associated with attention and motor tasks are altered in ADHD patients as compared to typically developing (TD) peers. We hypothesized that the behavioral improvement following medication in ADHD patients should be accompanied by a normalization in the modulation of such oscillations. We hence implemented a double-blind placebo-controlled crossover design, where boys diagnosed with ADHD underwent behavioral and MEG measurements during a spatial attention task while on and off stimulant medication (methylphenidate, MPH). Results were compared with an age/IQ-matched TD group performing the same task, to assess the effect of MPH on oscillatory activity in the alpha (7 – 13Hz) and beta (15 – 30Hz) bands. We observed that depression of beta band oscillation over motor cortex in preparation to the response in ADHD boys on placebo were significantly lower as compared to the TD group. Importantly MPH resulted in a normalization of the beta depression, which then reached the same levels as in the control subjects. Furthermore, alpha power increased during the preparation interval in the ADHD control group, supposedly reflecting working memory maintenance of the cue information. This increase was significantly reduced in the ADHD group on MPH, reflecting a reduced impact on working memory load. This is the first MEG study showing task related changes in brain oscillations with MPH in children with ADHD.Significance statementBrain oscillations in the alpha (7-13Hz) and beta (15-30Hz) frequency bands are thought to underly different aspects of attentional processing and their aberrant modulation has been reported in ADHD. Here, we used a child-friendly adaptation of a Posner cueing paradigm to investigate such oscillations in children with and without a diagnosis of ADHD, and further examined the effects of methylphenidate (MPH) in the latter group. We showed that MPH restores aberrant patterns of beta desynchronization and reduces alpha power during retention in the ADHD group, concomitant to an improvement in behavioural performance.

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Alpha Oscillations during Incidental Encoding Predict Subsequent Memory for New “Foil” Information

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01234 ◽

2018 ◽

Vol 30 (5) ◽

pp. 667-679 ◽

Cited By ~ 2

Author(s):

David A. Vogelsang ◽

Matthias Gruber ◽

Zara M. Bergström ◽

Charan Ranganath ◽

Jon S. Simons

Keyword(s):

Semantic Processing ◽

Temporal Dynamics ◽

Stimulus Onset ◽

Memory Test ◽

Oscillatory Activity ◽

Study Phase ◽

Alpha Power ◽

Alpha Oscillations ◽

Time Frequency ◽

Frontal Electrode

People can employ adaptive strategies to increase the likelihood that previously encoded information will be successfully retrieved. One such strategy is to constrain retrieval toward relevant information by reimplementing the neurocognitive processes that were engaged during encoding. Using EEG, we examined the temporal dynamics with which constraining retrieval toward semantic versus nonsemantic information affects the processing of new “foil” information encountered during a memory test. Time–frequency analysis of EEG data acquired during an initial study phase revealed that semantic compared with nonsemantic processing was associated with alpha decreases in a left frontal electrode cluster from around 600 msec after stimulus onset. Successful encoding of semantic versus nonsemantic foils during a subsequent memory test was related to decreases in alpha oscillatory activity in the same left frontal electrode cluster, which emerged relatively late in the trial at around 1000–1600 msec after stimulus onset. Across participants, left frontal alpha power elicited by semantic processing during the study phase correlated significantly with left frontal alpha power associated with semantic foil encoding during the memory test. Furthermore, larger left frontal alpha power decreases elicited by semantic foil encoding during the memory test predicted better subsequent semantic foil recognition in an additional surprise foil memory test, although this effect did not reach significance. These findings indicate that constraining retrieval toward semantic information involves reimplementing semantic encoding operations that are mediated by alpha oscillations and that such reimplementation occurs at a late stage of memory retrieval, perhaps reflecting additional monitoring processes.

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Alpha oscillations during incidental encoding predict subsequent memory for new “foil” information

10.1101/141648 ◽

2017 ◽

Cited By ~ 1

Author(s):

David A. Vogelsang ◽

Matthias Gruber ◽

Zara M. Bergström ◽

Charan Ranganath ◽

Jon S. Simons

Keyword(s):

Semantic Processing ◽

Semantic Information ◽

Stimulus Onset ◽

Memory Test ◽

Oscillatory Activity ◽

Study Phase ◽

Alpha Power ◽

Alpha Oscillations ◽

Time Frequency ◽

Frontal Electrode

AbstractPeople can employ adaptive strategies to increase the likelihood that previously encoded information will be successfully retrieved. One such strategy is to constrain retrieval towards relevant information by re-implementing the neurocognitive processes that were engaged during encoding. Using electroencephalography (EEG), we examined the temporal dynamics with which constraining retrieval towards semantic versus non-semantic information affects the processing of new “foil” information encountered during a memory test. Time-frequency analysis of EEG data acquired during an initial study phase revealed that semantic compared to non-semantic processing was associated with alpha decreases in a left frontal electrode cluster from around 600ms after stimulus onset. Successful encoding of semantic versus non-semantic foils during a subsequent memory test was related to decreases in alpha oscillatory activity in the same left frontal electrode cluster, which emerged relatively late in the trial at around 1000–1600ms after stimulus onset. Across subjects, left frontal alpha power elicited by semantic processing during the study phase correlated significantly with left frontal alpha power associated with semantic foil encoding during the memory test. Furthermore, larger left frontal alpha power decreases elicited by semantic foil encoding during the memory test predicted better subsequent semantic foil recognition in an additional surprise foil memory test. These findings indicate that constraining retrieval towards semantic information involves re-implementing semantic encoding operations that are mediated by alpha oscillations, and that such re-implementation occurs at a late stage of memory retrieval perhaps reflecting additional monitoring processes.

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Evaluation of Body Sway Using Tactile Stimuli on the Body Trunk

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.136.1135 ◽

2016 ◽

Vol 136 (8) ◽

pp. 1135-1141

Author(s):

Ryo Hasegawa ◽

Amir Maleki ◽

Masafumi Uchida

Keyword(s):

The Body ◽

Body Sway ◽

Tactile Stimuli

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Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy

Scientific Reports ◽

10.1038/s41598-021-89690-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jelena Trajkovic ◽

Francesco Di Gregorio ◽

Francesca Ferri ◽

Chiara Marzi ◽

Stefano Diciotti ◽

...

Keyword(s):

At Risk ◽

Resting State ◽

Right Hemisphere ◽

Normal Population ◽

Alpha Activity ◽

Oscillatory Activity ◽

Loop Current ◽

Clinical Tool ◽

Reliable Marker ◽

The Right

AbstractSchizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals).

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