Spatial specificity of alpha oscillations in the human visual system

Popov, Tzvetan; Gips, Bart; Kästner, Sabine; Jensen, Ole

doi:10.1002/hbm.24712

Cited by 50 publications

(46 citation statements)

References 66 publications

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“…Persistent processing has previously been observed during late visual processing and has been linked to high-level ventral visual cortex [ 6 ]. Alternatively, the timing observed here is also consistent with neuronal latencies of visual processing in memory-related circuits of the medial temporal lobe [ 25 ], as well as the timing of reinstatement of encoded memory signals during retrieval [ 26 , 27 , 28 , 29 , 30 ] that also show persistence [ 31 , 32 , 33 ].…”

Section: Resultssupporting

confidence: 80%

Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band

2020

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Summary To behave adaptively with sufficient flexibility, biological organisms must cognize beyond immediate reaction to a physically present stimulus. For this, humans use visual mental imagery [ 1 , 2 ], the ability to conjure up a vivid internal experience from memory that stands in for the percept of the stimulus. Visually imagined contents subjectively mimic perceived contents, suggesting that imagery and perception share common neural mechanisms. Using multivariate pattern analysis on human electroencephalography (EEG) data, we compared the oscillatory time courses of mental imagery and perception of objects. We found that representations shared between imagery and perception emerged specifically in the alpha frequency band. These representations were present in posterior, but not anterior, electrodes, suggesting an origin in parieto-occipital cortex. Comparison of the shared representations to computational models using representational similarity analysis revealed a relationship to later layers of deep neural networks trained on object representations, but not auditory or semantic models, suggesting representations of complex visual features as the basis of commonality. Together, our results identify and characterize alpha oscillations as a cortical signature of representations shared between visual mental imagery and perception.

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Section: Resultssupporting

confidence: 80%

Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band

2020

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“…The power of brain oscillations in the alpha frequency band (ϳ10 Hz) robustly tracks when humans shift their focus of attention between sensory modalities (Adrian, 1944;Fu et al, 2001;de Pesters et al, 2016), to time points of anticipated target presentation (Rohenkohl and Nobre, 2011; Payne et al, 2013), or to a particular location in space (Worden et al, 2000;Sauseng et al, 2005;Popov et al, 2019). Because alpha power drops in brain regions related to processing upcoming target stimuli (de Pesters et al, 2016), and because lower alpha power correlates with increased neural responses to the target (Gould et al, 2011;Wöstmann et al, 2019b) and enhanced behavioral measures of target detection (Thut et al, 2006), low alpha power is considered a signature of enhanced neural excitability to support target selection.…”

Section: Introductionmentioning

confidence: 99%

Alpha Oscillations in the Human Brain Implement Distractor Suppression Independent of Target Selection

2019

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In principle, selective attention is the net result of target selection and distractor suppression. The way in which both mechanisms are implemented neurally has remained contested. Neural oscillatory power in the alpha frequency band (ϳ10 Hz) has been implicated in the selection of to-be-attended targets, but there is lack of empirical evidence for its involvement in the suppression of to-be-ignored distractors. Here, we use electroencephalography recordings of N ϭ 33 human participants (males and females) to test the preregistered hypothesis that alpha power directly relates to distractor suppression and thus operates independently from target selection. In an auditory spatial pitch discrimination task, we modulated the location (left vs right) of either a target or a distractor tone sequence, while fixing the other in the front. When the distractor was fixed in the front, alpha power relatively decreased contralaterally to the target and increased ipsilaterally. Most importantly, when the target was fixed in the front, alpha lateralization reversed in direction for the suppression of distractors on the left versus right. These data show that target-selection-independent alpha power modulation is involved in distractor suppression. Although both lateralized alpha responses for selection and for suppression proved reliable, they were uncorrelated and distractor-related alpha power emerged from more anterior, frontal cortical regions. Lending functional significance to suppression-related alpha oscillations, alpha lateralization at the individual, single-trial level was predictive of behavioral accuracy. These results fuel a renewed look at neurobiological accounts of selection-independent suppressive filtering in attention.

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“…It could be that the induced visual cortical activity reflects multiple generators of oscillatory activity with heterogeneous phase relationships (Maris et al, 2016), thus prohibiting the estimated phase values to actually reflect the physiologically relevant phase. This possible explanation is supported by the presence of multiple generators of posterior alpha with different sensitivity to different visual locations (Popov et al, 2019). Another option is that visual representations might not be modulated in early visual cortex, but in downstream visual areas.…”

Section: Discussionmentioning

confidence: 99%

Phasic modulation of visual representations during sustained attention

Маршалл

Spaak

et al. 2020

Preprint

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Sustained attention has long been thought to benefit perception in a continuous fashion, but recent evidence suggests that it affects perception in a discrete, rhythmic way. Periodic fluctuations in behavioral performance over time, and modulations of behavioral performance by the phase of spontaneous oscillatory brain activity point to an attentional sampling rate in the theta or alpha frequency range. We investigated whether such discrete sampling by attention is reflected in periodic fluctuations in the decodability of visual stimulus orientation from magnetoencephalographic (MEG) brain signals. In this exploratory study, human subjects attended one of two grating stimuli while MEG was being recorded. We assessed the strength of the visual representation of the attended stimulus using a support vector machine (SVM) to decode the orientation of the grating (clockwise vs. counterclockwise) from the MEG signal. We tested whether decoder performance depended on the theta/alpha phase of local brain activity. While the phase of ongoing activity in visual cortex did not modulate decoding performance, theta/alpha phase of activity in the FEF and parietal cortex, contralateral to the attended stimulus did modulate decoding performance. These findings suggest that phasic modulations of visual stimulus representations in the brain are caused by frequency-specific top-down activity in the fronto-parietal attention network.

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Spatial specificity of alpha oscillations in the human visual system

Cited by 50 publications

References 66 publications

Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band

Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band

Alpha Oscillations in the Human Brain Implement Distractor Suppression Independent of Target Selection

Phasic modulation of visual representations during sustained attention

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