Olaf Dimigen

University of Gronigen

Visual fixation is an active process with pupil dynamics as well as fixational eye movements and microsaccades that support perception. Measures of both pupil contraction and microsaccades are known to be sensitive to ongoing cognition and emotional processing. Here we present experimental results from a visual fixation task demonstrating that pupi...

Two classic experimental paradigms: masked repetition priming and the boundary paradigm, have played a pivotal role in understanding the process of visual word recognition. Traditionally, these paradigms have often been employed by different communities of researchers, with their own long-standing research traditions. Nevertheless, a review of the...

Under natural viewing conditions, complex stimuli such as human faces are typically looked at several times in succession, implying that their recognition may unfold across multiple eye fixations. Although electrophysiological (EEG) experiments on face recognition typically prohibit eye movements, participants still execute frequent (micro)saccades...

Reading directions vary across writing systems. Through long-term experience readers adjust their visual systems to the dominant reading direction in their writing systems. However, little is known about the neural correlates underlying these adjustments because different writing systems do not just differ in reading direction, but also regarding v...

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Abstract The emotional expression and gaze direction of a face are...

The depth at which parafoveal words are processed during reading is an ongoing topic of debate. Recent studies using the RSVP-with-flanker paradigms have shown that a semantically implausible word in a sentence elicits a more negative N400 component than a plausible one already before the word enters foveal vision. While this finding suggests that...

In this work, we aimed to disentangle different influences of parafoveal words during reading using the RSVP-with-flanker paradigm. Specifically, in some previous studies, the effects of the semantic congruency of the parafoveal word (does it fit into the sentence context?) and the effect of the preview validity of the parafoveal word (is it a corr...

In many situations of everyday life, it is important to quickly understand a spoken message despite distraction by an already ongoing activity. Previous dual-task studies recording the N400 component of the event-related potential (ERP) have shown that auditory language comprehension can be strongly delayed by temporally overlapping additional task...

An influential theory in the field of visual object recognition proposes that it is the fast magnocellular (M) system that facilitates neural processing of spatially more fine-grained information rather the slower parvocellular (P) system. While written words can be considered as a special type of visual objects, it is unknown whether magnocellular...

Fixation-related potentials (FRPs), neural responses aligned to the end of saccades, are a promising tool for studying the dynamics of attention and cognition under natural viewing conditions. In the past, four methodological problems have complicated the analysis of such combined eye-tracking/electroencephalogram experiments: (1) the synchronizati...

An influential theory in the field of visual object recognition proposes that fast magnocellular (M) information facilitates neural processing of spatially more fine-grained but slower parvocellular (P) information. While written words can be considered as a special type of visual objects, it is unknown whether magnocellular facilitation also plays...

In this work, we aimed to disentangle different influences of parafoveal words during reading using the RSVP-with-flanker paradigm. Specifically, in some previous studies, the effects of the semantic congruency of the parafoveal word (does it fit into the sentence context?) and the effect of the preview validity of the parafoveal word (is it a corr...

Fixation-related potentials (FRPs), neural responses aligned to the end of saccades, are a promising tool for studying the dynamics of attention and cognition under natural viewing conditions. In the past, four methodological problems have complicated the analysis of such combined eye-tracking/electroencephalogram experiments: (1) the synchronizati...

Eye contact is a salient social cue, which is assumed to influence already early neural correlates of face perception. Specifically, the N170 component of the event-related potential (ERP) has often been found to be larger for faces with an averted gaze as compared to faces that directly look at the observer. In most existing ERP studies, effects o...

Humans actively sample their environment with saccadic eye movements to bring relevant information into high-acuity foveal vision. Despite being lower in resolution, peripheral information is also available before each saccade. How the pre-saccadic extrafoveal preview of a visual object influences its post-saccadic processing is still an unanswered...

Combining EEG with eye-tracking is a promising approach to study neural correlates of natural vision, but the resulting recordings are also heavily contaminated by activity of the eye balls, eye lids, and extraocular muscles. While Independent Component Analysis (ICA) is commonly used to suppress these ocular artifacts, its performance under free v...

In vision science, a particularly controversial topic is whether and how quickly the semantic information about objects is available outside foveal vision. Here, we aimed at contributing to this debate by coregistering eye movements and EEG while participants viewed photographs of indoor scenes that contained a semantically consistent or inconsiste...

Electrophysiological research with event-related brain potentials (ERPs) is increasingly moving from simple, strictly orthogonal stimulation paradigms towards more complex, quasi-experimental designs and naturalistic situations that involve fast, multisensory stimulation and complex motor behavior. As a result, electrophysiological responses from s...

Eye contact is a salient social cue which is assumed to influence early brain processes involved in face perception. The N170 component in the event-related potential (ERP) has frequently been reported to be larger to faces with an averted rather than direct gaze towards the observer. In most studies, however, this effect has been investigated in c...

Fixation-related potentials (FRPs), neural responses aligned to saccade offsets, are a promising tool to study the dynamics of attention and cognition under natural viewing conditions. In the past, four methodological problems have complicated the analysis of combined eye-tracking and EEG experiments: (i) the synchronization of data streams, (ii) t...

Saccade- or fixation-related potentials in EEG are a promising tool to study the temporaly dynamics of perception, attention, and cognition during natural vision. However, four data-analytic problems have complicated and/or confounded the analyis of multi-saccadic EEG experiments in the past. Problems related to data integration and ocular artifact...

The world appears stable despite saccadic eye-movements. One possible explanation for this phenomenon is that the visual system predicts upcoming input across saccadic eye-movements based on peripheral preview of the saccadic target. We tested this idea using concurrent electroencephalography (EEG) and eye-tracking. Participants made cued saccades...

Humans actively sample their environment with saccadic eye movements to bring relevant information into high-acuity foveal vision. Despite being lower in resolution, peripheral information is also available prior to each saccade. How pre-saccadic extrafoveal preview of a visual object influences its post-saccadic processing is still an unanswered q...

Attentional cueing tasks using gaze direction as spatial cues have sometimes yielded an early directing attention negativity (EDAN) component in the ERP, presumably reflecting the initial orienting toward the cued location. However, other studies have failed to identify an EDAN component for gaze cues, yielding an inconsistent picture. In the prese...

Combining EEG with eye-tracking is a promising approach to study neural correlates of natural vision, but the resulting recordings are also heavily contaminated by activity of the eye balls, eye lids, and extraocular muscles. While Independent Component Analysis (ICA) is commonly used to suppress these ocular artifacts, its performance under free v...

Electrophysiological research with event-related brain potentials (ERPs) is increasingly moving from simple, strictly orthogonal stimulation paradigms towards more complex, quasi-experimental designs and naturalistic situations that involve fast, multisensory stimulation and complex motor behavior. As a result, electrophysiological responses from s...

In vision science, a topic of great interest and considerable controversy is the processing of objects that are (in)consistent with the overall meaning of the scene in which they occur. How quickly can we access the semantic properties of objects and does this happen before the object is directly looked at? Here we brought novel evidences to this d...

Covert shifts of attention that follow the presentation of a cue are associated with lateralized components in the event-related potential (ERP): the " early directing attention negativity " (EDAN) and the " anterior directing attention negativity " (ADAN). Traditionally, these shifts are thought to take place while gaze is fixated and, thus, in th...

Visuospatial attention is an important mechanism in reading that governs the uptake of information from foveal and parafoveal regions of the visual field. However, the spatio-temporal dynamics of how attention is allocated during eye fixations are not completely understood. The current study explored the use of EEG alpha-band oscillations to invest...

During reading, the parafoveal processing of an upcoming word n+1 can influence word recognition in two ways: It can affect fixation behavior during the preceding fixation on word n (parafovea-on-fovea effect, POF), and it can facilitate subsequent foveal processing once word n+1 is fixated (preview benefit). While preview benefits are established,...

The Reading Acceleration Program (RAP), which uses adaptively increasing text erasure rates to enforce reading rate improvements, has been positively evaluated in various languages, reader and age groups. The current study compared the established incremental increase of text erasure rate with a training using fixed erasure rates in two groups of y...

Neural correlates of word recognition are commonly studied with serial visual presentation, a condition that eliminates three fundamental properties of natural reading: parafoveal preprocessing, saccade execution, and the fast changes in attentional processing load occurring from fixation to fixation. We combined eye-tracking and EEG to systematica...

Neural correlates of word recognition are commonly studied with serial visual presentation, a condition that eliminates three fundamental properties of natural reading: Parafoveal preprocessing, saccade execution, and the fast changes in attentional processing load occurring from fixation to fixation. We combined eye-tracking and EEG to systematica...

Natural reading involves the preprocessing of upcoming words, resulting in shorter fixations on words visible in the parafovea during preceding fixations. While this preview benefit is established in behavior, its brain-electric correlates have only recently been investigated. Using fixation-related potentials, an attenuation of the occipitotempora...

Readers differ considerably in their speed of self-paced reading. One factor known to influence fixation durations in reading is the preprocessing of words in parafoveal vision. Here we investigated whether individual differences in reading speed or the amount of information extracted from upcoming words (the preview benefit) can be explained by ba...

Obwohl Blickbewegungen einen elementaren Bestandteil des natürlichen Sehens darstellen, werden hirnelektrische Korrelate der visuellen Verarbeitung im Elektroenzephalogramm (EEG) zumeist während passiver Stimulation des ruhenden Auges erfasst. Ein alternativer methodischer Zugang ist die Kopplung des EEG an Beginn oder Ende natürlich auftretender A...

Cognitive conflict control in flanker tasks has often been described using the zoom-lens metaphor of selective attention. However, whether and how selective attention - in terms of suppression and enhancement - operates in this context has remained unclear. To examine the dynamic interplay of selective attention and cognitive control we used electr...

Covert shifts of visuospatial attention are traditionally assumed to occur in the absence of oculomotor behavior. In contrast, recent behavioral studies have linked attentional cueing effects to the occurrence of microsaccades, small eye movements executed involuntarily during attempted fixation. Here we used a new type of electrophysiological mark...

Reading requires the orchestration of vision, attention, and language processes, usually along with the programming of eye movements. The co-registration of eye movements and electroencephalography (EEG) during natural reading promises to deliver two complementary sets of information. Fixation durations reflect the difficulty of sublexical, lexical...

Microsaccades during fixation have been suggested to counteract visual fading. Recent experiments have also observed microsaccade-related neural responses from cellular record, scalp electroencephalogram (EEG), and functional magnetic resonance imaging (fMRI). The underlying mechanism, however, is not yet understood and highly debated. It has been...

Complex networks provide an excellent framework for studying the function of the human brain activity. Yet estimating functional networks from measured signals is not trivial, especially if the data is non-stationary and noisy as it is often the case with physiological recordings. In this article we propose a method that uses the local rank structu...

Three ERP experiments examined the effect of word presentation rate (i.e., stimulus onset asynchrony, SOA) on the time course of word frequency and predictability effects in sentence reading. In Experiments 1 and 2, sentences were presented word-by-word in the screen center at an SOA of 700 and 490 ms, respectively. While these rates are typical fo...

During natural reading, a parafoveal preview of the upcoming word facilitates its subsequent recognition (e.g., shorter fixation durations compared to masked preview) but nothing is known about the neural correlates of this so-called preview benefit. Furthermore, while the evidence is strong that readers preprocess orthographic features of upcoming...

Microsaccades (MS) are small (< 1°), involuntary eye movements that occur at an average rate of 1-2/sec during visual fixation. MS have received considerable attention by the EEG community after it was shown that muscle spikes from MS contaminate the gamma band (Yuval-Greenberg et al., 2008). At last ICON, we demonstrated that MS also generate size...

The development of theories and computational models of reading requires an understanding of processing constraints, in particular of timelines related to word recognition and oculomotor control. Timelines of word recognition are usually determined with event-related potentials (ERPs) recorded under conditions of serial visual presentation (SVP) of...

Brain-electric correlates of reading have traditionally been studied with word-by-word presentation, a condition that eliminates important aspects of the normal reading process and precludes direct comparisons between neural activity and oculomotor behavior. In the present study, we investigated effects of word predictability on eye movements (EM)...

Electrophysiological correlates of visual word recognition have typically been studied with single-word paradigms, or using word-by-word presentation (RSVP). An alternative approach to study word recognition under more natural conditions is to record fixation-related potentials (FRPs) time-locked to individual fixations during saccadic reading. Whi...

The recent years have seen the emergence of graph theoretical analysis of complex, functional brain networks estimated from neurophysiological measurements. The research has mainly focused on the graph characterization of the resting-state/default network, and its potential for clinical application. Functional resting-state networks usually display...

Microsaccades (MS) are small (< 1°), involuntary eye movements that occur at an average rate of 1-2/sec during visual fixation. MS have received considerable attention by the EEG community after it was shown that muscle spikes from MS contaminate the gamma band (Yuval-Greenberg et al., 2008). At last ICON, we demonstrated that MS also generate size...

It has been suggested that cognitive conflicts require effortful processing and, therefore, are aversive (Botvinick, 2007). In the present study, we compared conflicts emerging from the inhibition of a predominant response tendency in a go/no-go task with those between incompatible response activations in a Simon task in a within-subjects design, u...

Microsaccades are very small, involuntary flicks in eye position that occur on average once or twice per second during attempted visual fixation. Microsaccades give rise to EMG eye muscle spikes that can distort the spectrum of the scalp EEG and mimic increases in gamma band power. Here we demonstrate that microsaccades are also accompanied by genu...

In the recent past, recurrence quantification analysis (RQA) has gained an increasing interest in various research areas. The complexity measures the RQA provides have been useful in describing and analysing a broad range of data. It is known to be rather robust to noise and nonstationarities. Yet, one key question in empirical research concerns th...

It has recently been demonstrated that the presentation of visual oddballs induces a prolonged inhibition of microsaccades. The amplitude of the P300 component in event-related potentials (ERPs) has been shown to be sensitive to the category (target vs. nontarget) of the eliciting stimulus, its overall probability, and the preceding stimulus sequen...

Over the last years recurrence plots (RPs)and recurrence quantification analysis (RQA)have become quite popular in various branches of science. One key problem in applying RPs and RQA is the selection of suitable parameters for the data under investigation. Whereas various well-established methods for the selection of embedding parameters exists, t...

There is mounting evidence that under some conditions the processing of facial identity and facial emotional expressions may not be independent; however, the nature of this interaction remains to be established. By using event-related brain potentials (ERP) we attempted to localize these interactions within the information processing system. During...

About 15% of reading saccades move the eyes backwards in the text. To study the neurophysiological correlates of such regressions, we co-registered gaze position and ERPs of 54 subjects during natural, left-to-right reading. Sentences were grammatically diverse but contained no syntactic violations or local ambiguities. Accompanying the onset of lo...