The Simon effect towards memorized locations: EEG support for the involvement of attention

About a decade ago it was shown that the Simon effect, the tendency to react towards the side of a stimulus when its location is irrelevant, also occurs when stimuli have to be retrieved from memory. Recently, it was proposed that spatial attention may be responsible for this effect as it might select the relevant object in spatial working memory. An experiment employing the electroencephalogram (EEG) was carried out in which a colored frame (blue, yellow, green, or red) indicated what colored stimulus, one out of four presented in separate quadrants, was the target. The frame occurred either before, simultaneously with, or after the stimuli. In the latter case, the stimuli were first masked and were no longer visible, implying that they had to be retrieved from memory. Simon effects were observed in all conditions, implying that responses were also faster when the side of the to-be-memorized stimulus and the required response side corresponded. Importantly, determination of a newly derived EEG measure, the lateralized power spectra (LPS) in this condition revealed increased ipsilateral occipitoparietal power at around 500 ms after frame onset in the alpha band, supporting the view that attention was directed towards the location of the to-be-memorized item

Motor imagery, motor preparation, and motor execution of response sequences: Discrete response sequences being prepared, imagined, and executed

In this experiment, originally 24 participants took part. Due to either too many trials with EMG activity during motor imagery and too many EEG artefacts, only 14 participants are uploaded. The employed paradigm was already described in “The influence of motor imagery on the learning of a fine hand motor skill” authored by Jagna Sobierajewicz, Anna Prekoracka-Krawczyk, Wojciech Jaskowski, Willem B. Verwey, and Rob van der Lubbe, published in Experimental Brain Research (2016): DOI 10.1007/s00221-016-4794-2 The provided data processing steps (see description of the EEG data analyses) relate to another analysis than reported in the aforementioned paper. In the current analysis, the focus is on so-called event-related synchronization and desynchronization (ERS/ERD) in the theta, alpha, and beta bands. One of the questions to be addressed was whether frontal theta activity increases in the case of motor imagery as compared to motor execution and motor preparation

Comparing the effects of sustained and transient spatial attention on the orienting towards and the processing of electrical nociceptive stimuli: Mindfulness training, spatial attention, and EEG

In this research project we examined whether an 8-week Mindfulness training induces measurable changes effects of spatial atention on the orienting towards and the processing of nocicpetive stimuli as measured with EEG and SDT measures. We examined whether sustained vs. transient spatial attention differentially affect the processing of electrical nociceptive stimuli. Cued nociceptive stimuli of a relevant intensity (low or high) on the left or right forearm required a foot pedal press. The cued side varied trial wise in the transient attention condition, while it remained constant during a series of trials in the sustained attention condition. The orienting phase preceding the nociceptive stimuliwas examined by focusing on lateralized EEG activity. ERPswere computed to examine the influence of spatial attention on the processing of the nociceptive stimuli. Results for the orienting phase showed increased ipsilateral alpha and beta power above somatosensory areas in both the transient and the sustained attention conditions, which may reflect inhibition of ipsilateral and/or disinhibition of contralateral somatosensory areas. Cued nociceptive stimuli evoked a largerN130 than uncued stimuli, both in the transient and the sustained attention conditions. Support for increased efficiency of spatial attention in the sustained attention conditionwas obtained for the N180 and the P540 component. We concluded that spatial attention is more efficient in the case of sustained than in the case of transient spatial attentio

The influence of transient shifts of spatial attention on electrocutaneous stimulus evoked potentials

Background and Aims: Previous research revealed that processing of electrocutaneous stimuli is attenuated during sustained distraction tasks as compared to focused attention tasks, which is reflected in reduced N1 and P3a ERP components. Unknown, however, is whether transient shifts of spatial attention have the same attenuating effect. This issue was examined by employing a Posner‐cueing paradigm with electrocutaneous stimuli. Methods: Participants were presented with visual cues indicating the probable location (left or right forearm) of a to‐be‐discriminated electrocutaneous stimulus with a validity of 80%. Stimuli were of low or high intensity (manipulated by varying the number of pulses) and participants were instructed to make speeded responses depending on the perceived intensity by using two foot pedals. EEG was measured to determine the N1 and P3a ERP components. Results: Preliminary results show that knowledge of the probable forthcoming location of a stimulus affected the subsequent processing of this stimulus. Slower RTs were observed for invalidly cued as compared to validly cued stimuli. The N1 and P3a component were both enlarged for a high intensity compared to a low intensity stimulus. The N1 component was enhanced for attended as compared to unattended stimuli. In contrast, the P3a component, which is thought to reflect an orienting response, was enhanced for unattended as compared to attended stimuli. Conclusions: A transient manipulation of focused attention increases cortical activity for attended as compared to unattended electrocutaneous stimuli. Furthermore, initially unattended stimuli appear to induce an enhanced orienting effect

Failure of the extended contingent attentional capture account in multimodal settings

Sudden changes in our environment like sound bursts or light flashes are thought to automatically attract our attention thereby affecting responses to subsequent targets, although an alternative view (the contingent attentional capture account) holds that stimuli only capture our attention when they match target features. In the current study, we examined whether an extended version of the latter view can explain exogenous cuing effects on speed and accuracy of performance to targets (uncued-cued) in multimodal settings, in which auditory and visual stimuli co-occur. To this end, we determined whether observed effects of visual and auditory cues, which were always intermixed, depend on top-down settings in “pure” blocks, in which only one target modality occurred, as compared to “mixed” blocks, in which targets were either visual or auditory. Results revealed that unimodal and crossmodal cuing effects depend on top-down settings. However, our findingswerenot in accordance with predictions derived from the extended contingent attentional capture account. Specifically, visualcues showed comparable effects for visual targets in pure and mixed blocks, but also a comparable effect for auditory targets in pure blocks, and most surprisingly, an opposite effect in mixed blocks. The latter result suggests that visual stimuli may distract attention from the auditory modality in case when the modality of the forthcoming target is unknown. The results additionally revealed that the Simon effect, the influence of correspondence or not between stimulus and response side, is modulated by exogenous cues in unimodal settings, but not in crossmodal settings. These findingsaccord with the view that attention plays an important role for the Simon effect, and additionally questions the directness of links between maps of visual and auditory space