Publications by authors named "Freek van Ede"

50 Publications

Decoding visual colour from scalp electroencephalography measurements.

Neuroimage 2021 Apr 6:118030. Epub 2021 Apr 6.

Department of Experimental Psychology, University of Oxford, Oxford, UK.

Recent advances have made it possible to decode various aspects of visually presented stimuli from patterns of scalp EEG measurements. As of recently, such multivariate methods have been commonly used to decode visual-spatial features such as location, orientation, or spatial frequency. In the current proof-of-principle study, we show that it is also possible to track visual colour processing by using Linear Discriminant Analysis. Building on other recent demonstrations, we show that colour decoding: (1) reflects sensory qualities (as opposed to, for example, verbal labelling) with a prominent contribution from posterior electrodes contralateral to the stimulus, (2) conforms to a parametric coding space, (3) is possible in multi-item displays, and (4) is comparable in magnitude to the decoding of visual stimulus orientation. Through subsampling our data, we also provide an estimate of the approximate number of trials and participants required for robust decoding. Colour decoding opens a relevant new dimension in which to track visual processing using scalp EEG measurements, while bypassing potential confounds associated with decoding approaches that focus on spatial features.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118030DOI Listing
April 2021

Output planning at the input stage in visual working memory.

Sci Adv 2021 Mar 24;7(13). Epub 2021 Mar 24.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Working memory serves as the buffer between past sensations and future behavior, making it vital to understand not only how we encode and retain sensory information in memory but also how we plan for its upcoming use. We ask when prospective action goals emerge alongside the encoding and retention of visual information in working memory. We show that prospective action plans do not emerge gradually during memory delays but are brought into memory early, in tandem with sensory encoding. This action encoding (i) precedes a second stage of action preparation that adapts to the time of expected memory utilization, (ii) occurs even ahead of an intervening motor task, and (iii) predicts visual memory-guided behavior several seconds later. By bringing prospective action plans into working memory at an early stage, the brain creates a dual (visual-motor) memory code that can make memories more effective and robust for serving ensuing behavior.
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http://dx.doi.org/10.1126/sciadv.abe8212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7990334PMC
March 2021

Functional biases in attentional templates from associative memory.

J Vis 2020 12;20(13)

Department of Experimental Psychology, University of Oxford, Oxford, UK.

In everyday life, attentional templates-which facilitate the perception of task-relevant sensory inputs-are often based on associations in long-term memory. We ask whether templates retrieved from memory are necessarily faithful reproductions of the encoded information or if associative-memory templates can be functionally adapted after retrieval in service of current task demands. Participants learned associations between four shapes and four colored gratings, each with a characteristic combination of color (green or pink) and orientation (left or right tilt). On each trial, observers saw one shape followed by a grating and indicated whether the pair matched the learned shape-grating association. Across experimental blocks, we manipulated the types of nonmatch (lure) gratings most often presented. In some blocks the lures were most likely to differ in color but not tilt, whereas in other blocks this was reversed. If participants functionally adapt the retrieved template such that the distinguishing information between lures and targets is prioritized, then they should overemphasize the most commonly diagnostic feature dimension within the template. We found evidence for this in the behavioral responses to the lures: participants were more accurate and faster when responding to common versus rare lures, as predicted by the functional-but not the strictly veridical-template hypothesis. This shows that templates retrieved from memory can be functionally biased to optimize task performance in a flexible, context-dependent, manner.
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http://dx.doi.org/10.1167/jov.20.13.7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7729124PMC
December 2020

Visual working memory and action: Functional links and bi-directional influences.

Authors:
Freek van Ede

Vis cogn 2020 May 12;28(5-8):401-413. Epub 2020 May 12.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Working memory bridges perception to action over extended delays, enabling flexible goal-directed behaviour. To date, studies of visual working memory - concerned with detailed visual representations such as shape and colour - have considered visual memory predominantly in the context of visual task demands, such as visual identification and search. Another key purpose of visual working memory is to directly inform and guide upcoming actions. Taking this as a starting point, I review emerging evidence for the pervasive bi-directional links between visual working memory and (planned) action, and discuss these links from the perspective of their common goal of enabling flexible and precise behaviour.
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http://dx.doi.org/10.1080/13506285.2020.1759744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655037PMC
May 2020

Goal-directed and stimulus-driven selection of internal representations.

Proc Natl Acad Sci U S A 2020 09 14;117(39):24590-24598. Epub 2020 Sep 14.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford OX3 7JX, United Kingdom.

Adaptive behavior relies on the selection of relevant sensory information from both the external environment and internal memory representations. In understanding external selection, a classic distinction is made between voluntary (goal-directed) and involuntary (stimulus-driven) guidance of attention. We have developed a task-the anti-retrocue task-to separate and examine voluntary and involuntary guidance of attention to internal representations in visual working memory. We show that both voluntary and involuntary factors influence memory performance but do so in distinct ways. Moreover, by tracking gaze biases linked to attentional focusing in memory, we provide direct evidence for an involuntary "retro-capture" effect whereby external stimuli involuntarily trigger the selection of feature-matching internal representations. We show that stimulus-driven and goal-directed influences compete for selection in memory, and that the balance of this competition-as reflected in oculomotor signatures of internal attention-predicts the quality of ensuing memory-guided behavior. Thus, goal-directed and stimulus-driven factors together determine the fate not only of perception, but also of internal representations in working memory.
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http://dx.doi.org/10.1073/pnas.2013432117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7533705PMC
September 2020

Purpose-Dependent Consequences of Temporal Expectations Serving Perception and Action.

J Neurosci 2020 10 8;40(41):7877-7886. Epub 2020 Sep 8.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford OX3 7JX, United Kingdom.

Temporal expectations enable anticipatory brain states that prepare us for upcoming perception and action. We investigated the purpose-dependent nature and consequences of cued temporal expectations on brain and behavior in male and female human volunteers, using two matched visual-motor tasks that stressed either response speed or visual accuracy. We show that the consequences of temporal expectations are fundamentally purpose dependent. Temporal expectations predominantly affected response times when visual demands were low and speed was more important, but perceptual accuracy when visual demands were more challenging. Using magnetoencephalography, we further show how temporal expectations latch onto anticipatory neural states associated with concurrent spatial expectations-modulating task-specific anticipatory neural lateralization of oscillatory brain activity in a modality- and frequency-specific manner. By relating these brain states to behavior, we finally reveal how the behavioral relevance of such anticipatory brain states is similarly purpose dependent. Knowing when events may occur helps to prepare neural activity for upcoming perception and action. It is becoming increasingly clear that distinct sources of temporal expectations may facilitate performance via distinct mechanisms. Another relevant dimension to consider regards the distinct purposes that temporal expectations may serve. Here, we demonstrate that the consequences of temporal expectations on neurophysiological brain activity and behavior are fundamentally purpose dependent, and show how temporal expectations interact with task-relevant neural states in a modality- and frequency-specific manner. This brings the important insight that the ways in which temporal expectations influence brain and behavior, and how brain activity is related to behavior, are not fixed properties but rather depend on the task at hand.
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http://dx.doi.org/10.1523/JNEUROSCI.1134-20.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7548698PMC
October 2020

Temporal Expectations Prepare Visual Working Memory for Behavior.

J Cogn Neurosci 2020 12 8;32(12):2320-2332. Epub 2020 Sep 8.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging.

Working memory enables us to retain past sensations in service of anticipated task demands. How we prepare for anticipated task demands during working memory retention remains poorly understood. Here, we focused on the role of time-asking how temporal expectations help prepare for ensuing memory-guided behavior. We manipulated the expected probe time in a delayed change-detection task and report that temporal expectation can have a profound influence on memory-guided behavioral performance. EEG measurements corroborated the utilization of temporal expectations: demonstrating the involvement of a classic EEG signature of temporal expectation-the contingent negative variation-in the context of working memory. We also report the influence of temporal expectations on 2 EEG signatures associated with visual working memory-the lateralization of 8- to 12-Hz alpha activity, and the contralateral delay activity. We observed a dissociation between these signatures, whereby alpha lateralization (but not the contralateral delay activity) adapted to the time of expected memory utilization. These data show how temporal expectations prepare visual working memory for behavior and shed new light on the electrophysiological markers of both temporal expectation and working memory.
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http://dx.doi.org/10.1162/jocn_a_01626DOI Listing
December 2020

Comparing the prioritization of items and feature-dimensions in visual working memory.

J Vis 2020 08;20(8):25

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, UK.

Selective attention can be directed not only to external sensory inputs, but also to internal sensory representations held within visual working memory (VWM). To date, this phenomenon has been studied predominantly following retrospective cues directing attention to particular items, or their locations in memory. In addition to item-level attentional prioritization, recent studies have shown that selectively attending to feature dimensions in VWM can also improve memory recall performance. However, no study to date has directly compared item-based and dimension-based attention in VWM, nor their neural bases. Here, we compared the benefits of retrospective cues (retro-cues) that were directed either at a multifeature item or at a feature dimension that was shared between two spatially segregated items. Behavioral results revealed qualitatively similar attentional benefits in both recall accuracy and response time, but also showed that cueing benefits were larger after item cues. Concurrent electroencephalogram measurements further revealed a similar attenuation of posterior alpha oscillations following both item and dimension retro-cues when compared with noninformative, neutral retro-cues. We argue that attention can act flexibly to prioritize the most relevant information-at either the item or the dimension level-to optimize ensuing memory-based task performance, and we discuss the implications of the observed commonalities and differences between item-level and dimension-level prioritization in VWM.
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http://dx.doi.org/10.1167/jov.20.8.25DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453048PMC
August 2020

One Thing Leads to Another: Anticipating Visual Object Identity Based on Associative-Memory Templates.

J Neurosci 2020 05 13;40(20):4010-4020. Epub 2020 Apr 13.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford OX3 7JX, United Kingdom.

Probabilistic associations between stimuli afford memory templates that guide perception through proactive anticipatory mechanisms. A great deal of work has examined the behavioral consequences and human electrophysiological substrates of anticipation following probabilistic memory cues that carry spatial or temporal information to guide perception. However, less is understood about the electrophysiological substrates linked to anticipating the sensory content of events based on recurring associations between successive events. Here, we demonstrate behavioral and electrophysiological signatures of using associative-memory templates to guide perception, while equating spatial and temporal anticipation (experiments 1 and 2), as well as target probability and response demands (experiment 2). By recording the electroencephalogram in the two experiments ( = 55; 24 females), we show that two markers in human electrophysiology implicated in spatial and temporal anticipation also contribute to the anticipation of perceptual identity, as follows: attenuation of alpha-band oscillations and the contingent negative variation (CNV). Together, our results show that memory-guided identity templates proactively impact perception and are associated with anticipatory states of attenuated alpha oscillations and the CNV. Furthermore, by isolating object-identity anticipation from spatial and temporal anticipation, our results suggest a role for alpha attenuation and the CNV in specific visual content anticipation beyond general changes in neural excitability or readiness. Probabilistic associations between stimuli afford memory templates that guide perception through proactive anticipatory mechanisms. The current work isolates the behavioral benefits and electrophysiological signatures of memory-guided identity-based anticipation, while equating anticipation of space, time, motor responses, and task relevance. Our results show that anticipation of the specific identity of a forthcoming percept impacts performance and is associated with states of attenuated alpha oscillations and the contingent negative variation, extending previous work implicating these neural substrates in spatial and temporal preparatory attention. Together, this work bridges fields of attention, memory, and perception, providing new insights into the neural mechanisms that support complex attentional templates.
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http://dx.doi.org/10.1523/JNEUROSCI.2751-19.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7219293PMC
May 2020

Dissecting beta-state changes during timed movement preparation in Parkinson's disease.

Prog Neurobiol 2020 01 25;184:101731. Epub 2019 Nov 25.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, United Kingdom; Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom. Electronic address:

An emerging perspective describes beta-band (15-28 Hz) activity as consisting of short-lived high-amplitude events that only appear sustained in conventional measures of trial-average power. This has important implications for characterising abnormalities observed in beta-band activity in disorders like Parkinson's disease. Measuring parameters associated with beta-event dynamics may yield more sensitive measures, provide more selective diagnostic neural markers, and provide greater mechanistic insight into the breakdown of brain dynamics in this disease. Here, we used magnetoencephalography in eighteen Parkinson's disease participants off dopaminergic medication and eighteen healthy control participants to investigate beta-event dynamics during timed movement preparation. We used the Hidden Markov Model to classify event dynamics in a data-driven manner and derived three parameters of beta events: (1) beta-state amplitude, (2) beta-state lifetime, and (3) beta-state interval time. Of these, changes in beta-state interval time explained the overall decreases in beta power during timed movement preparation and uniquely captured the impairment in such preparation in patients with Parkinson's disease. Thus, the increased granularity of the Hidden Markov Model analysis (compared with conventional analysis of power) provides increased sensitivity and suggests a possible reason for impairments of timed movement preparation in Parkinson's disease.
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http://dx.doi.org/10.1016/j.pneurobio.2019.101731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6977086PMC
January 2020

Eyes Wide Shut: Gaze dynamics without vision, Symposium 6 at the 20th European Conference on Eye Movement Research (ECEM) in Alicante, 21.8.2019.

J Eye Mov Res 2019 Nov 25;12(7). Epub 2019 Nov 25.

State University of New York, Downstate Medical Center, USA.

The human ability for visualization extends far beyond the physical items that surround us. We are able to dismiss the constant influx of photons hitting our retinas, and instead picture the layout of our kindergarten classroom, envision the gently swaying palm trees of our dream vacation, or foresee the face of a yet-to-be-born child. As we inspect imaginary objects and people with our mind's eye, our corporeal eyeballs latch onto the fantasy. Research has found that our eyes can move as if seeing, even when there is nothing to look at. Thus, gaze explorations in the absence of actual vision have been reported in many contexts, including in visualization and memory tasks, and perhaps even during REM sleep. This symposium will present the manifold aspects of gaze dynamics in conditions when the visual input is impoverished or altogether absent. Presentations will address the characteristics of large and small eye movements during imagined and remembered scenes, the impact of visual field deficits on oculomotor control, and the role of eye movements in the future development of neural prosthetics for the blind. https://vimeo.com/365522806.
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http://dx.doi.org/10.16910/jemr.12.7.12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7917488PMC
November 2019

Unpacking Transient Event Dynamics in Electrophysiological Power Spectra.

Brain Topogr 2019 11 21;32(6):1020-1034. Epub 2019 Nov 21.

Department of Psychiatry, Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.

Electrophysiological recordings of neuronal activity show spontaneous and task-dependent changes in their frequency-domain power spectra. These changes are conventionally interpreted as modulations in the amplitude of underlying oscillations. However, this overlooks the possibility of underlying transient spectral 'bursts' or events whose dynamics can map to changes in trial-average spectral power in numerous ways. Under this emerging perspective, a key challenge is to perform burst detection, i.e. to characterise single-trial transient spectral events, in a principled manner. Here, we describe how transient spectral events can be operationalised and estimated using Hidden Markov Models (HMMs). The HMM overcomes a number of the limitations of the standard amplitude-thresholding approach to burst detection; in that it is able to concurrently detect different types of bursts, each with distinct spectral content, without the need to predefine frequency bands of interest, and does so with less dependence on a priori threshold specification. We describe how the HMM can be used for burst detection and illustrate its benefits on simulated data. Finally, we apply this method to empirical data to detect multiple burst types in a task-MEG dataset, and illustrate how we can compute burst metrics, such as the task-evoked timecourse of burst duration.
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http://dx.doi.org/10.1007/s10548-019-00745-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6882750PMC
November 2019

Under the Mind's Hood: What We Have Learned by Watching the Brain at Work.

J Neurosci 2020 01 19;40(1):89-100. Epub 2019 Oct 19.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford OX3 7JX, United Kingdom, and.

Imagine you were asked to investigate the workings of an engine, but to do so without ever opening the hood. Now imagine the engine fueled the human mind. This is the challenge faced by cognitive neuroscientists worldwide aiming to understand the neural bases of our psychological functions. Luckily, human ingenuity comes to the rescue. Around the same time as the Society for Neuroscience was being established in the 1960s, the first tools for measuring the human brain at work were becoming available. Noninvasive human brain imaging and neurophysiology have continued developing at a relentless pace ever since. In this 50 year anniversary, we reflect on how these methods have been changing our understanding of how brain supports mind.
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http://dx.doi.org/10.1523/JNEUROSCI.0742-19.2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939481PMC
January 2020

Human gaze tracks attentional focusing in memorized visual space.

Nat Hum Behav 2019 05 4;3(5):462-470. Epub 2019 Mar 4.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Brain areas that control gaze are also recruited for covert shifts of spatial attention. In the external space of perception, there is a natural ecological link between the control of gaze and spatial attention, as information sampled at covertly attended locations can inform where to look next. Attention can also be directed internally to representations held within the spatial layout of visual working memory. In such cases, the incentive for using attention to direct gaze disappears, as there are no external targets to scan. Here we investigate whether the oculomotor system of the brain also participates in attention focusing within the internal space of memory. Paradoxically, we reveal this participation through gaze behaviour itself. We demonstrate that selecting an item from visual working memory biases gaze in the direction of the memorized location of that item, despite there being nothing to look at and location memory never explicitly being probed. This retrospective 'gaze bias' occurs only when an item is not already in the internal focus of attention, and it predicts the performance benefit associated with the focusing of internal attention. We conclude that the oculomotor system also participates in focusing attention within memorized space, leaving traces all the way to the eyes.
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http://dx.doi.org/10.1038/s41562-019-0549-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6546593PMC
May 2019

Theta oscillations in 4-year-olds are sensitive to task engagement and task demands.

Sci Rep 2019 04 15;9(1):6049. Epub 2019 Apr 15.

Donders Institute for Brain Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.

Top-down control processes are essential for guiding attention and working memory towards task-relevant information. Recently, theta oscillations were suggested as critical for these cognitive processes. Infant studies testing a mixture of bottom-up and top-down processes support adult theta findings. Yet, since infants cannot be instructed, it remains unclear to what extent theta oscillations are involved particularly in top-down control in early childhood. That is especially relevant towards school age when children need top-down control to solve the increasingly complex tasks. In this EEG study, we investigated whether theta-power in 4-year-olds is sensitive to task engagement and to different cognitive task demands. In a within-subjects design, children had three different instructions before watching videos including either no demands (No Task), language-related (Color-naming Task), or action-related (Imitation Task) demands. We analyzed children's theta-power (3-6 Hz) in two contrasts: (1) Task vs. No Task and (2) Color-naming vs. Imitation Task. The findings revealed more frontomedial theta-power when children were engaged in a task and their frontomedial theta-power increased during their cognitive engagement. Theta-power was stronger over left fronto-temporal sites for language- compared to action-related demands. These findings support recent theoretical work highlighting theta oscillations in top-down control and extend this neurocognitive framework to preschoolers.
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http://dx.doi.org/10.1038/s41598-019-42615-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465288PMC
April 2019

Time for What? Breaking Down Temporal Anticipation.

Trends Neurosci 2019 06 15;42(6):373-374. Epub 2019 Mar 15.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, UK. Electronic address:

A variety of environmental regularities enable us to anticipate the timing of upcoming sensations and actions. A recent article (Breska and Ivry, Proc. Natl. Acad. Sci. U. S. A. 2018;115:12283-12288) reports a striking neural double dissociation between two distinct varieties of temporal anticipation. Looking forward, we consider further dissociations according to the goals for which temporal anticipation is used.
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http://dx.doi.org/10.1016/j.tins.2019.03.002DOI Listing
June 2019

The Functional Consequences of Social Attention for Memory-guided Attention Orienting and Anticipatory Neural Dynamics.

J Cogn Neurosci 2019 05 6;31(5):686-698. Epub 2019 Feb 6.

University of Oxford.

Social attention when viewing natural social (compared with nonsocial) images has functional consequences on contextual memory in healthy human adults. In addition to attention affecting memory performance, strong evidence suggests that memory, in turn, affects attentional orienting. Here, we ask whether the effects of social processing on memory alter subsequent memory-guided attention orienting and corresponding anticipatory dynamics of 8-12 Hz alpha-band oscillations as measured with EEG. Eighteen young adults searched for targets in scenes that contained either social or nonsocial distracters and their memory precision tested. Subsequently, RT was measured as participants oriented to targets appearing in those scenes at either valid (previously learned) locations or invalid (different) locations. Memory precision was poorer for target locations in social scenes. In addition, distractor type moderated the validity effect during memory-guided attentional orienting, with a larger cost in RT when targets appeared at invalid (different) locations within scenes with social distractors. The poorer memory performance was also marked by reduced anticipatory dynamics of spatially lateralized 8-12 Hz alpha-band oscillations for scenes with social distractors. The functional consequences of a social attention bias therefore extend from memory to memory-guided attention orienting, a bidirectional chain that may further reinforce attentional biases.
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http://dx.doi.org/10.1162/jocn_a_01379DOI Listing
May 2019

Concurrent visual and motor selection during visual working memory guided action.

Nat Neurosci 2019 03 4;22(3):477-483. Epub 2019 Feb 4.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Visual working memory enables us to hold onto past sensations in anticipation that these may become relevant for guiding future actions. Yet laboratory tasks have treated visual working memories in isolation from their prospective actions and have focused on the mechanisms of memory retention rather than utilization. To understand how visual memories become used for action, we linked individual memory items to particular actions and independently tracked the neural dynamics of visual and motor selection when memories became used for action. This revealed concurrent visual-motor selection, engaging appropriate visual and motor brain areas at the same time. Thus we show that items in visual working memory can invoke multiple, item-specific, action plans that can be accessed together with the visual representations that guide them, affording fast and precise memory-guided behavior.
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http://dx.doi.org/10.1038/s41593-018-0335-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6420070PMC
March 2019

Early Behavioural Facilitation by Temporal Expectations in Complex Visual-motor Sequences.

Neuroscience 2018 10 24;389:74-84. Epub 2018 May 24.

Oxford Centre for Human Brain Activity, Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK; Brain and Cognition Lab, Department of Experimental Psychology, Tinbergen Building, 9 South Parks Road, Oxford OX1 3UD, UK. Electronic address:

In daily life, temporal expectations may derive from incidental learning of recurring patterns of intervals. We investigated the incidental acquisition and utilisation of combined temporal-ordinal (spatial/effector) structure in complex visual-motor sequences using a modified version of a serial reaction time (SRT) task. In this task, not only the series of targets/responses, but also the series of intervals between subsequent targets was repeated across multiple presentations of the same sequence. Each participant completed three sessions. In the first session, only the repeating sequence was presented. During the second and third session, occasional probe blocks were presented, where a new (unlearned) spatial-temporal sequence was introduced. We first confirm that participants not only got faster over time, but that they were slower and less accurate during probe blocks, indicating that they incidentally learned the sequence structure. Having established a robust behavioural benefit induced by the repeating spatial-temporal sequence, we next addressed our central hypothesis that implicit temporal orienting (evoked by the learned temporal structure) would have the largest influence on performance for targets following short (as opposed to longer) intervals between temporally structured sequence elements, paralleling classical observations in tasks using explicit temporal cues. We found that indeed, reaction time differences between new and repeated sequences were largest for the short interval, compared to the medium and long intervals, and that this was the case, even when comparing late blocks (where the repeated sequence had been incidentally learned), to early blocks (where this sequence was still unfamiliar). We conclude that incidentally acquired temporal expectations that follow a sequential structure can have a robust facilitatory influence on visually-guided behavioural responses and that, like more explicit forms of temporal orienting, this effect is most pronounced for sequence elements that are expected at short inter-element intervals.
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http://dx.doi.org/10.1016/j.neuroscience.2018.05.014DOI Listing
October 2018

Neural Oscillations: Sustained Rhythms or Transient Burst-Events?

Trends Neurosci 2018 07 5;41(7):415-417. Epub 2018 May 5.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK; Department of Experimental Psychology, University of Oxford, Oxford, UK.

Frequency-specific patterns of neural activity are increasingly interpreted as transient bursts of isolated events rather than as rhythmically sustained oscillations. This has potentially far-reaching implications for theories of how such oscillations originate and how they shape neural computations. As this debate unfolds, we explore alternative interpretations and ask how best to distinguish between them.
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http://dx.doi.org/10.1016/j.tins.2018.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024376PMC
July 2018

Anticipatory neural dynamics of spatial-temporal orienting of attention in younger and older adults.

Neuroimage 2018 09 4;178:46-56. Epub 2018 May 4.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, UK; Brain and Cognition Lab, Department of Experimental Psychology, University of Oxford, UK. Electronic address:

Spatial and temporal expectations act synergistically to facilitate visual perception. In the current study, we sought to investigate the anticipatory oscillatory markers of combined spatial-temporal orienting and to test whether these decline with ageing. We examined anticipatory neural dynamics associated with joint spatial-temporal orienting of attention using magnetoencephalography (MEG) in both younger and older adults. Participants performed a cued covert spatial-temporal orienting task requiring the discrimination of a visual target. Cues indicated both where and when targets would appear. In both age groups, valid spatial-temporal cues significantly enhanced perceptual sensitivity and reduced reaction times. In the MEG data, the main effect of spatial orienting was the lateralised anticipatory modulation of posterior alpha and beta oscillations. In contrast to previous reports, this modulation was not attenuated in older adults; instead it was even more pronounced. The main effect of temporal orienting was a bilateral suppression of posterior alpha and beta oscillations. This effect was restricted to younger adults. Our results also revealed a striking interaction between anticipatory spatial and temporal orienting in the gamma-band (60-75 Hz). When considering both age groups separately, this effect was only clearly evident and only survived statistical evaluation in the older adults. Together, these observations provide several new insights into the neural dynamics supporting separate as well as combined effects of spatial and temporal orienting of attention, and suggest that different neural dynamics associated with attentional orienting appear differentially sensitive to ageing.
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http://dx.doi.org/10.1016/j.neuroimage.2018.05.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057272PMC
September 2018

Impaired corticomuscular and interhemispheric cortical beta oscillation coupling in amyotrophic lateral sclerosis.

Clin Neurophysiol 2018 07 6;129(7):1479-1489. Epub 2018 Apr 6.

Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK. Electronic address:

Objectives: The neural activity of the primary motor cortex is variably synchronised with contralateral peripheral electromyographic signals, which is thought to facilitate long-range communication through the motor system. Such corticomuscular coherence (CMC) is typically observed in the beta-band (15-30 Hz) range during steady force production. We aimed to measure pathological alteration to CMC resulting from ALS.

Methods: CMC was appraised during a forearm grip task in 17 ALS patients contrasted against age-matched healthy controls. An exploratory comparison with a group of asymptomatic ALS gene carriers and neuropathy disease mimics was also undertaken. Neural signals were acquired by whole-head magnetoencephalography and localised via structural MRI to the motor cortices.

Results: During light voluntary muscular contraction, beta-band CMC was significantly reduced in ALS patients compared to healthy controls. Propagation of motoric beta rhythms across the cortical hemispheres was also shown to be impaired in ALS patients. CMC was preserved in the asymptomatic gene carrier and did not distinguish ALS patients from neuropathy mimics.

Conclusion: Functional connectivity metrics reveal an ALS-related decrease in both corticomuscular and interhemispheric communication during bilateral grip force production.

Significance: MEG-derived beta oscillation coupling may be a potential biomarker of motor system dysfunction in ALS, against which to measure future therapeutic efficacy.
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http://dx.doi.org/10.1016/j.clinph.2018.03.019DOI Listing
July 2018

Decoding the influence of anticipatory states on visual perception in the presence of temporal distractors.

Nat Commun 2018 04 13;9(1):1449. Epub 2018 Apr 13.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, OX3 7JX, UK.

Anticipatory states help prioritise relevant perceptual targets over competing distractor stimuli and amplify early brain responses to these targets. Here we combine electroencephalography recordings in humans with multivariate stimulus decoding to address whether anticipation also increases the amount of target identity information contained in these responses, and to ask how targets are prioritised over distractors when these compete in time. We show that anticipatory cues not only boost visual target representations, but also delay the interference on these target representations caused by temporally adjacent distractor stimuli-possibly marking a protective window reserved for high-fidelity target processing. Enhanced target decoding and distractor resistance are further predicted by the attenuation of posterior 8-14 Hz alpha oscillations. These findings thus reveal multiple mechanisms by which anticipatory states help prioritise targets from temporally competing distractors, and they highlight the potential of non-invasive multivariate electrophysiology to track cognitive influences on perception in temporally crowded contexts.
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http://dx.doi.org/10.1038/s41467-018-03960-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899132PMC
April 2018

Anticipated moments: temporal structure in attention.

Nat Rev Neurosci 2018 Jan 7;19(1):34-48. Epub 2017 Dec 7.

Department of Experimental Psychology, Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford OX3 7JX, UK.

We have come to recognize the brain as a predictive organ, anticipating attributes of the incoming sensory stimulation to guide perception and action in the service of adaptive behaviour. In the quest to understand the neural bases of the modulatory prospective signals that prioritize and select relevant events during perception, one fundamental dimension has until recently been largely overlooked: time. In this Review, we introduce the burgeoning field of temporal attention and illustrate how the brain makes use of various forms of temporal regularities in the environment to guide adaptive behaviour and influence neural processing.
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http://dx.doi.org/10.1038/nrn.2017.141DOI Listing
January 2018

Mnemonic and attentional roles for states of attenuated alpha oscillations in perceptual working memory: a review.

Authors:
Freek van Ede

Eur J Neurosci 2018 10 22;48(7):2509-2515. Epub 2017 Nov 22.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Alpha oscillations are often reported to be amplified during working memory (WM) retention, serving to disengage sensory areas to protect internal representations from external interference. At the same time, contemporary views of WM postulate that sensory areas may often also be recruited for retention. I here review recent evidence that during such 'perceptual' WM, alpha oscillations in mnemonically relevant sensory areas are not amplified but attenuated instead. I will argue that such attenuated alpha states serve a mnemonic role and, further, that larger attenuation may support item-specific attentional prioritisation within perceptual WM. In critically evaluating this role, I also consider (and argue against) four alternatives to a strictly mnemonic account of the available data that may also prove useful to consider in future research. Finally, I highlight key implications of these data for the study of WM and for our understanding of the functional roles of states of attenuated alpha oscillations in cognition.
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http://dx.doi.org/10.1111/ejn.13759DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220786PMC
October 2018

Temporal alignment of anticipatory motor cortical beta lateralisation in hidden visual-motor sequences.

Eur J Neurosci 2018 10 6;48(8):2684-2695. Epub 2017 Nov 6.

Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.

Performance improves when participants respond to events that are structured in repeating sequences, suggesting that learning can lead to proactive anticipatory preparation. Whereas most sequence-learning studies have emphasised spatial structure, most sequences also contain a prominent temporal structure. We used MEG to investigate spatial and temporal anticipatory neural dynamics in a modified serial reaction time (SRT) task. Performance and brain activity were compared between blocks with learned spatial-temporal sequences and blocks with new sequences. After confirming a strong behavioural benefit of spatial-temporal predictability, we show lateralisation of beta oscillations in anticipation of the response associated with the upcoming target location and show that this also aligns to the expected timing of these forthcoming events. This effect was found both when comparing between repeated (learned) and new (unlearned) sequences, as well as when comparing targets that were expected after short vs. long intervals within the repeated (learned) sequence. Our findings suggest that learning of spatial-temporal structure leads to proactive and dynamic modulation of motor cortical excitability in anticipation of both the location and timing of events that are relevant to guide action.
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http://dx.doi.org/10.1111/ejn.13700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220967PMC
October 2018

Effect of Field Spread on Resting-State Magneto Encephalography Functional Network Analysis: A Computational Modeling Study.

Brain Connect 2017 11 27;7(9):541-557. Epub 2017 Oct 27.

1 Computational Neuroscience Group, Center for Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain .

A popular way to analyze resting-state electroencephalography (EEG) and magneto encephalography (MEG) data is to treat them as a functional network in which sensors are identified with nodes and the interaction between channel time series and the network connections. Although conceptually appealing, the network-theoretical approach to sensor-level EEG and MEG data is challenged by the fact that EEG and MEG time series are mixtures of source activity. It is, therefore, of interest to assess the relationship between functional networks of source activity and the ensuing sensor-level networks. Since these topological features are of high interest in experimental studies, we address the question of to what extent the network topology can be reconstructed from sensor-level functional connectivity (FC) measures in case of MEG data. Simple simulations that consider only a small number of regions do not allow to assess network properties; therefore, we use a diffusion magnetic resonance imaging-constrained whole-brain computational model of resting-state activity. Our motivation lies behind the fact that still many contributions found in the literature perform network analysis at sensor level, and we aim at showing the discrepancies between source- and sensor-level network topologies by using realistic simulations of resting-state cortical activity. Our main findings are that the effect of field spread on network topology depends on the type of interaction (instantaneous or lagged) and leads to an underestimation of lagged FC at sensor level due to instantaneous mixing of cortical signals, instantaneous interaction is more sensitive to field spread than lagged interaction, and discrepancies are reduced when using planar gradiometers rather than axial gradiometers. We, therefore, recommend using lagged interaction measures on planar gradiometer data when investigating network properties of resting-state sensor-level MEG data.
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http://dx.doi.org/10.1089/brain.2017.0525DOI Listing
November 2017

Supramodal Theta, Gamma, and Sustained Fields Predict Modality-specific Modulations of Alpha and Beta Oscillations during Visual and Tactile Working Memory.

J Cogn Neurosci 2017 Aug 30;29(8):1455-1472. Epub 2017 Mar 30.

Radboud University.

Flexible control over currently relevant sensory representations is an essential feature of primate cognition. We investigated the neurophysiological bases of such flexible control in humans during an intermodal working memory task in which participants retained visual or tactile sequences. Using magnetoencephalography, we first show that working memory retention engages early visual and somatosensory areas, as reflected in the sustained load-dependent suppression of alpha and beta oscillations. Next, we identify three components that are also load dependent but modality independent: medial prefrontal theta synchronization, frontoparietal gamma synchronization, and sustained parietal event-related fields. Critically, these domain-general components predict (across trials and within load conditions) the modality-specific suppression of alpha and beta oscillations, with largely unique contributions per component. Thus, working memory engages multiple complementary frontoparietal components that have discernible neuronal dynamics and that flexibly modulate retention-related activity in sensory areas in a manner that tracks the current contents of working memory.
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http://dx.doi.org/10.1162/jocn_a_01129DOI Listing
August 2017

Driving Human Motor Cortical Oscillations Leads to Behaviorally Relevant Changes in Local GABA Inhibition: A tACS-TMS Study.

J Neurosci 2017 04 27;37(17):4481-4492. Epub 2017 Mar 27.

Oxford Centre for fMRI of the Brain, Nuffield Department of Clinical Neurosciences, and.

Beta and gamma oscillations are the dominant oscillatory activity in the human motor cortex (M1). However, their physiological basis and precise functional significance remain poorly understood. Here, we used transcranial magnetic stimulation (TMS) to examine the physiological basis and behavioral relevance of driving beta and gamma oscillatory activity in the human M1 using transcranial alternating current stimulation (tACS). tACS was applied using a sham-controlled crossover design at individualized intensity for 20 min and TMS was performed at rest (before, during, and after tACS) and during movement preparation (before and after tACS). We demonstrated that driving gamma frequency oscillations using tACS led to a significant, duration-dependent decrease in local resting-state GABA inhibition, as quantified by short interval intracortical inhibition. The magnitude of this effect was positively correlated with the magnitude of GABA decrease during movement preparation, when gamma activity in motor circuitry is known to increase. In addition, gamma tACS-induced change in GABA inhibition was closely related to performance in a motor learning task such that subjects who demonstrated a greater increase in GABA inhibition also showed faster short-term learning. The findings presented here contribute to our understanding of the neurophysiological basis of motor rhythms and suggest that tACS may have similar physiological effects to endogenously driven local oscillatory activity. Moreover, the ability to modulate local interneuronal circuits by tACS in a behaviorally relevant manner provides a basis for tACS as a putative therapeutic intervention. Gamma oscillations have a vital role in motor control. Using a combined tACS-TMS approach, we demonstrate that driving gamma frequency oscillations modulates GABA inhibition in the human motor cortex. Moreover, there is a clear relationship between the change in magnitude of GABA inhibition induced by tACS and the magnitude of GABA inhibition observed during task-related synchronization of oscillations in inhibitory interneuronal circuits, supporting the hypothesis that tACS engages endogenous oscillatory circuits. We also show that an individual's physiological response to tACS is closely related to their ability to learn a motor task. These findings contribute to our understanding of the neurophysiological basis of motor rhythms and their behavioral relevance and offer the possibility of developing tACS as a therapeutic tool.
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http://dx.doi.org/10.1523/JNEUROSCI.0098-17.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5413186PMC
April 2017

Early behavioural facilitation by temporal expectations in complex visual-motor sequences.

J Physiol Paris 2016 11 18;110(4 Pt B):487-496. Epub 2017 Mar 18.

Oxford Centre for Human Brain Activity, Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK; Brain and Cognition Lab, Department of Experimental Psychology, Tinbergen Building, 9 South Parks Road, Oxford OX1 3UD, UK. Electronic address:

In daily life, temporal expectations may derive from incidental learning of recurring patterns of intervals. We investigated the incidental acquisition and utilisation of combined temporal-ordinal (spatial/effector) structure in complex visual-motor sequences using a modified version of a serial reaction time (SRT) task. In this task, not only the series of targets/responses, but also the series of intervals between subsequent targets was repeated across multiple presentations of the same sequence. Each participant completed three sessions. In the first session, only the repeating sequence was presented. During the second and third session, occasional probe blocks were presented, where a new (unlearned) spatial-temporal sequence was introduced. We first confirm that participants not only got faster over time, but that they were slower and less accurate during probe blocks, indicating that they incidentally learned the sequence structure. Having established a robust behavioural benefit induced by the repeating spatial-temporal sequence, we next addressed our central hypothesis that implicit temporal orienting (evoked by the learned temporal structure) would have the largest influence on performance for targets following short (as opposed to longer) intervals between temporally structured sequence elements, paralleling classical observations in tasks using explicit temporal cues. We found that indeed, reaction time differences between new and repeated sequences were largest for the short interval, compared to the medium and long intervals, and that this was the case, even when comparing late blocks (where the repeated sequence had been incidentally learned), to early blocks (where this sequence was still unfamiliar). We conclude that incidentally acquired temporal expectations that follow a sequential structure can have a robust facilitatory influence on visually-guided behavioural responses and that, like more explicit forms of temporal orienting, this effect is most pronounced for sequence elements that are expected at short inter-element intervals.
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http://dx.doi.org/10.1016/j.jphysparis.2017.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742633PMC
November 2016