scholarly journals Hemispheric asymmetry of globus pallidus relates to alpha modulation in reward-related attentional tasks

2018 ◽  
Author(s):  
C. Mazzetti ◽  
T. Staudigl ◽  
T. R. Marshall ◽  
J. M. Zumer ◽  
S. J. Fallon ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Globus Pallidus ◽  
Alpha Activity ◽  
Hemispheric Lateralization ◽  
Monetary Reward ◽  
Alpha Power ◽  
Alpha Band ◽  
Subcortical Structures ◽  
Attention Task ◽  
Subcortical Regions

AbstractWhile subcortical structures like the basal ganglia have been widely explored in relation to motor control, recent evidence suggests that their mechanisms extend to the domain of attentional switching. We here investigated the subcortical involvement in reward related top-down control of visual alpha-band oscillations (8 – 13 Hz), which have been consistently linked to mechanisms supporting the allocation of visuo-spatial attention. Given that items associated with contextual saliency (e.g. monetary reward or loss) attract attention, it is not surprising that the acquired salience of visual items further modulates. The executive networks controlling such reward-dependent modulations of oscillatory brain activity have yet to be fully elucidated. Although such networks have been explored in terms of cortico-cortical interactions, subcortical regions are likely to be involved. To uncover this, we combined MRI and MEG data from 17 male and 11 female participants, investigating whether derived measures of subcortical structural asymmetries predict interhemispheric modulation of alpha power during a spatial attention task. We show that volumetric hemispheric lateralization of globus pallidus (GP) and thalamus (Th) explains individual hemispheric biases in the ability to modulate posterior alpha power. Importantly, for the GP, this effect became stronger when the value-saliency parings in the task increased. Our findings suggest that the GP and Th in humans are part of a subcortical executive control network, differentially involved in modulating posterior alpha activity in the presence of saliency. Further investigation aimed at uncovering the interaction between subcortical and neocortical attentional networks would provide useful insight in future studies.Significance statementWhile the involvement of subcortical regions into higher level cognitive processing, such as attention and reward attribution, has been already indicated in previous studies, little is known about its relationship with the functional oscillatory underpinnings of said processes. In particular, interhemispheric modulation of alpha band (8-13Hz) oscillations, as recorded with magnetoencephalography (MEG), has been previously shown to vary as a function of salience (i.e. monetary reward/loss) in a spatial attention task. We here provide novel insights into the link between subcortical and cortical control of visual attention. Using the same reward-related spatial attention paradigm, we show that the volumetric lateralization of subcortical structures (specifically Globus Pallidus and Thalamus) explains individual biases in the modulation of visual alpha activity.

scholarly journals Alpha Activity Reflects the Magnitude of an Individual Bias in Human Perception

2019 ◽  
Author(s):  
Laetitia Grabot ◽  
Christoph Kayser
Keyword(s):  
Sensory Information ◽  
Human Perception ◽  
Alpha Activity ◽  
Subjective Perception ◽  
Alpha Power ◽  
Potential Candidate ◽  
Alpha Band ◽  
Temporal Recalibration ◽  
Neural Underpinnings ◽  
Band Activity

AbstractBiases in sensory perception can arise from both experimental manipulations and personal trait-like features. These idiosyncratic biases and their neural underpinnings are often overlooked in studies on the physiology underlying perception. A potential candidate mechanism reflecting such idiosyncratic biases could be spontaneous alpha band activity, a prominent brain rhythm known to influence perceptual reports in general. Using a temporal order judgement task, we here tested the hypothesis that alpha power reflects the overcoming of an idiosyncratic bias. Importantly, to understand the interplay between idiosyncratic biases and contextual (temporary) biases induced by experimental manipulations, we quantified this relation before and after temporal recalibration. Using EEG recordings in human participants (male and female), we find that pre-stimulus frontal alpha power correlates with the tendency to respond relative to an own idiosyncratic bias, with stronger alpha leading to responses matching the bias. In contrast, alpha power does not predict response correctness. These results also hold after temporal recalibration and are specific to the alpha band, suggesting that alpha band activity reflects, directly or indirectly, processes that help to overcome an individual’s momentary bias in perception. We propose that combined with established roles of parietal alpha in the encoding of sensory information frontal alpha reflects complementary mechanisms influencing perceptual decisions.Significance statementThe brain is a biased organ, frequently generating systematically distorted percepts of the world, leading each of us to evolve in our own subjective reality. However, such biases are often overlooked or considered noise when studying the neural mechanisms underlying perception. We show that spontaneous alpha band activity predicts the degree of biasedness of human choices in a time perception task, suggesting that alpha activity indexes processes needed to overcome an individual’s idiosyncratic bias. This result provides a window onto the neural underpinnings of subjective perception, and offers the possibility to quantify or manipulate such priors in future studies.

scholarly journals Alpha-band Activity Tracks the Zoom Lens of Attention

2020 ◽  
Vol 32 (2) ◽  
pp. 272-282
Author(s):  
Tobias Feldmann-Wüstefeld ◽  
Edward Awh
Keyword(s):  
Spatial Attention ◽  
Sensory Information ◽  
Alpha Activity ◽  
Target Display ◽  
Zoom Lens ◽  
Alpha Band ◽  
Discrimination Accuracy ◽  
Spatial Selectivity ◽  
Baseline Shift ◽  
Band Activity

Voluntary control over spatial attention has been likened to the operation of a zoom lens, such that processing quality declines as the size of the attended region increases, with a gradient of performance that peaks at the center of the selected area. Although concurrent changes in activity in visual regions suggest that zoom lens adjustments influence perceptual stages of processing, extant work has not distinguished between changes in the spatial selectivity of attention-driven neural activity and baseline shift of activity that can increase mean levels of activity without changes in selectivity. Here, we distinguished between these alternatives by measuring EEG activity in humans to track preparatory changes in alpha activity that indexed the precise topography of attention across the possible target positions. We observed increased spatial selectivity in alpha activity when observers voluntarily directed attention toward a narrower region of space, a pattern that was mirrored in target discrimination accuracy. Thus, alpha activity tracks both the centroid and spatial extent of covert spatial attention before the onset of the target display, lending support to the hypothesis that narrowing the zoom lens of attention shapes the initial encoding of sensory information.

scholarly journals Spatiotemporal dynamics of auditory attention synchronize with speech

2016 ◽  
Vol 113 (14) ◽  
pp. 3873-3878 ◽  
Author(s):  
Malte Wöstmann ◽  
Björn Herrmann ◽  
Burkhard Maess ◽  
Jonas Obleser
Keyword(s):  
Spatial Attention ◽  
Time Course ◽  
Speech Rate ◽  
Temporal Structure ◽  
Low Frequency ◽  
Spatial Location ◽  
Brain Regions ◽  
Hemispheric Lateralization ◽  
Speech Comprehension ◽  
Alpha Power

Attention plays a fundamental role in selectively processing stimuli in our environment despite distraction. Spatial attention induces increasing and decreasing power of neural alpha oscillations (8–12 Hz) in brain regions ipsilateral and contralateral to the locus of attention, respectively. This study tested whether the hemispheric lateralization of alpha power codes not just the spatial location but also the temporal structure of the stimulus. Participants attended to spoken digits presented to one ear and ignored tightly synchronized distracting digits presented to the other ear. In the magnetoencephalogram, spatial attention induced lateralization of alpha power in parietal, but notably also in auditory cortical regions. This alpha power lateralization was not maintained steadily but fluctuated in synchrony with the speech rate and lagged the time course of low-frequency (1–5 Hz) sensory synchronization. Higher amplitude of alpha power modulation at the speech rate was predictive of a listener’s enhanced performance of stream-specific speech comprehension. Our findings demonstrate that alpha power lateralization is modulated in tune with the sensory input and acts as a spatiotemporal filter controlling the read-out of sensory content.

Somatosensory Anticipatory Alpha Activity Increases to Suppress Distracting Input

2012 ◽  
Vol 24 (3) ◽  
pp. 677-685 ◽  
Author(s):  
Saskia Haegens ◽  
Lisa Luther ◽  
Ole Jensen
Keyword(s):  
Task Performance ◽  
Discrimination Task ◽  
Discrimination Performance ◽  
Alpha Activity ◽  
Task Demands ◽  
Alpha Power ◽  
Alpha Band ◽  
Stimulus Detection ◽  
Engagement And Disengagement ◽  
Band Activity

Effective processing of sensory input in daily life requires attentional selection and amplification of relevant input and, just as importantly, attenuation of irrelevant information. It has been proposed that top–down modulation of oscillatory alpha band activity (8–14 Hz) serves to allocate resources to various regions, depending on task demands. In previous work, we showed that contralateral somatosensory alpha activity decreases to facilitate processing of an anticipated target stimulus in a tactile discrimination task. In the current study, we asked whether somatosensory alpha activity is also modulated when expecting incoming distracting stimuli on the nonattended side. We hypothesized that an ipsilateral increase of alpha to suppress distracters would be required for optimal task performance. We recorded magneto-encephalography while subjects performed a tactile stimulus discrimination task where a cue directed attention either to their left or right hand. Distracters were presented simultaneously to the unattended hand. We found that alpha power contralateral to the attended hand decreased, whereas ipsilateral alpha power increased. In addition, posterior alpha power showed a general increase. Importantly, these three alpha components all contributed to discrimination performance. This study further extends the notion that alpha band activity is involved in shaping the functional architecture of the working brain by determining the engagement and disengagement of specific regions: Contralateral alpha decreases to facilitate stimulus detection, whereas ipsilateral alpha increases when active suppression of distracters is required. Importantly, the ipsilateral alpha increase is crucial for optimal task performance.

scholarly journals Decoding and Reconstructing the Focus of Spatial Attention from the Topography of Alpha-band Oscillations

2016 ◽  
Vol 28 (8) ◽  
pp. 1090-1097 ◽  
Author(s):  
Jason Samaha ◽  
Thomas C. Sprague ◽  
Bradley R. Postle
Keyword(s):  
Spatial Attention ◽  
Sustained Attention ◽  
Spatial Location ◽  
Covert Attention ◽  
Alpha Power ◽  
Alpha Band ◽  
Temporal Precision ◽  
Neural Populations ◽  
Stimulus Features ◽  
Spatial Locations

Many aspects of perception and cognition are supported by activity in neural populations that are tuned to different stimulus features (e.g., orientation, spatial location, color). Goal-directed behavior, such as sustained attention, requires a mechanism for the selective prioritization of contextually appropriate representations. A candidate mechanism of sustained spatial attention is neural activity in the alpha band (8–13 Hz), whose power in the human EEG covaries with the focus of covert attention. Here, we applied an inverted encoding model to assess whether spatially selective neural responses could be recovered from the topography of alpha-band oscillations during spatial attention. Participants were cued to covertly attend to one of six spatial locations arranged concentrically around fixation while EEG was recorded. A linear classifier applied to EEG data during sustained attention demonstrated successful classification of the attended location from the topography of alpha power, although not from other frequency bands. We next sought to reconstruct the focus of spatial attention over time by applying inverted encoding models to the topography of alpha power and phase. Alpha power, but not phase, allowed for robust reconstructions of the specific attended location beginning around 450 msec postcue, an onset earlier than previous reports. These results demonstrate that posterior alpha-band oscillations can be used to track activity in feature-selective neural populations with high temporal precision during the deployment of covert spatial attention.

scholarly journals Orienting auditory attention in time: Lateralized alpha power reflects spatio-temporal filtering

2020 ◽  
Author(s):  
Malte Wöstmann ◽  
Burkhard Maess ◽  
Jonas Obleser
Keyword(s):  
Spatial Attention ◽  
Presentation Rate ◽  
Hemispheric Lateralization ◽  
Alpha Power ◽  
Temporal Filtering ◽  
Temporal Cues ◽  
Temporal Filter ◽  
Spatio Temporal ◽  
Filter Mechanism ◽  
Attentional Filter

AbstractThe deployment of neural alpha (8-12 Hz) lateralization in service of spatial attention is well-established: Alpha power increases in the cortical hemisphere ipsilateral to the attended hemifield, and decreases in the contralateral hemisphere, respectively. Much less is known about humans’ ability to deploy such alpha lateralization in time, and to thus exploit alpha power as a spatio-temporal filter. Here we show that spatially lateralized alpha power does signify - beyond the direction of spatial attention - the distribution of attention in time and thereby qualifies as a spatio-temporal attentional filter. Participants (N = 20) selectively listened to spoken numbers presented on one side (left vs right), while competing numbers were presented on the other side. Key to our hypothesis, temporal foreknowledge was manipulated via a visual cue, which was either instructive and indicated the to-be-probed number position (70% valid) or neutral. Temporal foreknowledge did guide participants’ attention, as they recognized numbers from the to-be-attended side more accurately following valid cues. In the magnetoencephalogram (MEG), spatial attention to the left versus right side induced lateralization of alpha power in all temporal cueing conditions. Modulation of alpha lateralization at the 0.8-Hz presentation rate of spoken numbers was stronger following instructive compared to neutral temporal cues. Critically, we found stronger modulation of lateralized alpha power specifically at the onsets of temporally cued numbers. These results suggest that the precisely timed hemispheric lateralization of alpha power qualifies as a spatio-temporal attentional filter mechanism susceptible to top-down behavioural goals.

scholarly journals Suppression of alpha-band power underlies exogenous attention to emotional distractors

2021 ◽  
Author(s):  
Lydia Arana ◽  
María Melcón ◽  
Dominique Kessel ◽  
Sandra Hoyos ◽  
Jacobo Albert ◽  
...  
Keyword(s):  
Alpha Activity ◽  
Exogenous Attention ◽  
Alpha Power ◽  
List Type ◽  
Adaptive Mechanism ◽  
Alpha Band ◽  
Voluntary Attention ◽  
Distractor Location ◽  
Efficient Detection ◽  
Band Activity

AbstractAlpha-band oscillations (8-14 Hz) are essential for attention and perception processes by facilitating the selection of relevant information. Directing visuospatial endogenous (voluntary) attention to a given location consistently results in a power suppression of alpha activity over occipito-parietal areas contralateral to the attended visual field. In contrast, the neural oscillatory dynamics underlying the involuntary capture of attention, or exogenous attention, are currently under debate. By exploiting the inherent capacity of emotionally salient visual stimuli to capture attention, we aimed to investigate whether exogenous attention is characterized by either a reduction or an increase in alpha-band activity. Electroencephalographic activity was recorded while participants completed a Posner visuospatial cueing task, in which a lateralized image with either positive, negative, or neutral emotional content competed with a target stimulus presented in the opposite hemifield. Compared with trials with no distractors, alpha power was reduced over occipital regions contralateral to distracting images. This reduction of alpha activity turned out to be functionally relevant, as it correlated with impaired behavioural performance on the ongoing task and was enhanced for distractors with negative valence. Taken together, our results demonstrate that visuospatial exogenous attention is characterized by a suppression of alpha-band activity contralateral to distractor location, similar to the oscillatory underpinnings of endogenous attention. Further, these results highlight the key role of exogenous attention as an adaptive mechanism for the efficient detection of biologically salient stimuli.HighlightsExogenous attention is indexed by alpha suppression contralateral to distractors.Alpha power decrease is enhanced by distractors with negative emotional valence.Lower levels of alpha power correlate with poorer task performance accuracy.The negativity bias in exogenous attention might reflect an adaptive mechanism.

scholarly journals Probing the limits of alpha power lateralization as a neural marker of selective attention in middle-aged and older listeners

2018 ◽  
Author(s):  
Sarah Tune ◽  
Malte Wöstmann ◽  
Jonas Obleser
Keyword(s):  
Task Performance ◽  
Spatial Attention ◽  
Healthy Aging ◽  
Individual Variability ◽  
Auditory Attention ◽  
Hemispheric Lateralization ◽  
Alpha Power ◽  
Middle Aged ◽  
Auditory Spatial Attention ◽  
Neural Marker

AbstractIn recent years, hemispheric lateralization of alpha power has emerged as a neural mechanism thought to underpin spatial attention across sensory modalities. Yet, how healthy aging, beginning in middle adulthood, impacts the modulation of lateralized alpha power supporting auditory attention remains poorly understood. In the current electroencephalography (EEG) study, middle-aged and older adults (N = 29; ~40-70 years) performed a dichotic listening task that simulates a challenging, multi-talker scenario. We examined the extent to which the modulation of 8-12 Hz alpha power would serve as neural marker of listening success across age. With respect to the increase in inter-individual variability with age, we examined an extensive battery of behavioral, perceptual, and neural measures. Similar to findings on younger adults, middle-aged and older listeners′ auditory spatial attention induced robust lateralization of alpha power, which synchronized with the speech rate. Notably, the observed relationship between this alpha lateralization and task performance did not co-vary with age. Instead, task performance was strongly related to an individual’s attentional and working memory capacity. Multivariate analyses revealed a separation of neural and behavioral variables independent of age. Our results suggest that in age-varying samples as the present one, the lateralization of alpha power is neither a sufficient nor necessary neural strategy for an individual’s auditory spatial attention, as higher age might come with increased use of alternative, compensatory mechanisms. Our findings emphasize that explaining inter-individual variability will be key to understanding the role of alpha oscillations in auditory attention in the aging listener.

scholarly journals Alpha oscillations do not implement gain control in early visual cortex but rather gating in parieto-occipital regions

2020 ◽  
Author(s):  
Alexander Zhigalov ◽  
Ole Jensen
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Neuronal Excitability ◽  
Brain Activity ◽  
Gain Control ◽  
Alpha Power ◽  
Alpha Band ◽  
Alpha Oscillations ◽  
Early Visual Cortex ◽  
Broadband Frequency

AbstractSpatial attention provides a mechanism for respectively enhancing relevant and suppressing irrelevant information. While it is well-established that attention modulates oscillations in the alpha band, it remains unclear if alpha oscillations are involved in directly modulating the neuronal excitability associated with the allocation of spatial attention. In this study in humans, we utilized a novel broadband frequency (60 – 70 Hz) tagging paradigm to quantify neuronal excitability in relation to alpha oscillations in a spatial attention paradigm. We used magnetoencephalography to characterize ongoing brain activity as it allows for localizing the sources of both the alpha and frequency tagging responses. We found that attentional modulation of alpha power and the frequency tagging response are uncorrelated over trials. Importantly, the neuronal sources of the tagging response were localized in early visual cortex (V1) whereas the sources of the alpha activity were identified around parieto-occipital sulcus. Moreover, we found that attention did not modulate the latency of the frequency tagged responses. Our findings point to alpha band oscillations serving a downstream gating role rather than implementing gain control of excitability in early visual regions.Significance StatementBy combining magnetoencephalography and a novel broadband frequency tagging approach, we show that spatial attention differently modulates alpha oscillations and neuronal excitability. Importantly, the sources of the alpha oscillations and tagging responses were spatially distinct and the alpha power and tagging response were not related over trials. These results are inconsistent with previous ideas suggesting that alpha oscillations are involved in gain control of early sensory regions; rather alpha oscillations are involved in the allocation of neuronal resources in downstream regions.

Sign in / Sign up

Export Citation Format

Share Document