Cross-modal Attention Effects Research Articles

Cross-modal attention effects in vestibular cortex during attentive tracking of moving objects

Cross-modal attention effects in vestibular cortex during attentive tracking of moving objects

Examining the role of a medial olivocochlear reflex elicitor on the attentional modulation of cochlear function

Selective attention has been shown to modulate cortical and subcortical neural representations of sound in the auditory systems of humans and research animals. Neuroanatomy of the auditory system suggests that cortical activity is capable of modulating cochlear responses to sound via corticofugal projections to the medial olivocochlear (MOC) efferent system. Several human studies using otoacoustic emissions (OAEs) suggest that selective attention can modulate cochlear responses to sound, but results across studies typically show small and inconsistent effects. Recent work in our laboratory has demonstrated much larger effects of cross-modal selective attention on cochlear processing than previously reported, likely due to improved methods for measuring MOC effects. One unanswered question is whether selective attention can modulate cochlear function directly, or whether it only modulates stimulus-elicited MOC activity. Our current study compares OAE magnitudes measured while participants attend to auditor...

Cross-Modal Attention Effects in the Vestibular Cortex during Attentive Tracking of Moving Objects.

In this study we investigate cross-modal attention effects in the human vestibular cortex. We applied the visual multiple-object tracking task because it is known to evoke attentional load effects on neural activity in visual motion-processing and attention-processing areas. Here we demonstrate a load-dependent effect of attention on the activation in the vestibular cortex, despite constant visual motion stimulation. We find that activity in the parietoinsular vestibular cortex is more strongly suppressed the greater the attentional load on the visual tracking task. These findings suggest cross-modal attentional modulation in the vestibular cortex.

Auditory Processing under Cross-Modal Visual Load Investigated with Simultaneous EEG-fMRI

Cognitive task demands in one sensory modality (T1) can have beneficial effects on a secondary task (T2) in a different modality, due to reduced top-down control needed to inhibit the secondary task, as well as crossmodal spread of attention. This contrasts findings of cognitive load compromising a secondary modality’s processing. We manipulated cognitive load within one modality (visual) and studied the consequences of cognitive demands on secondary (auditory) processing. 15 healthy participants underwent a simultaneous EEG-fMRI experiment. Data from 8 participants were obtained outside the scanner for validation purposes. The primary task (T1) was to respond to a visual working memory (WM) task with four conditions, while the secondary task (T2) consisted of an auditory oddball stream, which participants were asked to ignore. The fMRI results revealed fronto-parietal WM network activations in response to T1 task manipulation. This was accompanied by significantly higher reaction times and lower hit rates with increasing task difficulty which confirmed successful manipulation of WM load. Amplitudes of auditory evoked potentials, representing fundamental auditory processing showed a continuous augmentation which demonstrated a systematic relation to cross-modal cognitive load. With increasing WM load, primary auditory cortices were increasingly deactivated while psychophysiological interaction results suggested the emergence of auditory cortices connectivity with visual WM regions. These results suggest differential effects of crossmodal attention on fundamental auditory processing. We suggest a continuous allocation of resources to brain regions processing primary tasks when challenging the central executive under high cognitive load.

Effects of cross-modal selective attention on the sensory periphery: Cochlear sensitivity is altered by selective attention

There is increasing evidence that alterations in the focus of attention result in changes in neural responding at the most peripheral levels of the auditory system. To date, however, those studies have not ruled out differences in task demands or overall arousal in explaining differences in responding across intermodal attentional conditions. The present study sought to compare changes in the response of cochlear outer hair cells, employing distortion product otoacoustic emissions (DPOAEs), under different, balanced conditions of intermodal attention. DPOAEs were measured while the participants counted infrequent, brief exemplars of the DPOAE primary tones (auditory attending), and while counting visual targets, which were instances of Gabor gradient phase shifts (visual attending). Corroborating an earlier study from our laboratory, the results show that DPOAEs recorded in the auditory-ignoring condition were significantly higher in overall amplitude, compared with DPOAEs recorded while participants attended to the eliciting primaries; a finding in apparent contradiction with more central measures of intermodal attention. Also consistent with our previous findings, DPOAE rapid adaptation, believed to be mediated by the medial olivocochlear efferents (MOC), was unaffected by changes in intermodal attention. The present findings indicate that manipulations in the conditions of attention, through the corticofugal pathway, and its last relay to cochlear outer hair cells (OHCs), the MOC, alter cochlear sensitivity to sound. These data also suggest that the MOC influence on OHC sensitivity is composed of two independent processes, one of which is under attentional control.

Crossmodal attention alters auditory contrast sensitivity

We examined the influence of covert, endogenous, crossmodal attention on auditory contrast sensitivity in a two-interval forced-choice dual-task paradigm. Attending to a visual stimulus has been found to alter the visual contrast response function via a mechanism of contrast gain for sustained visual attention, or a combination of response gain and contrast gain for transient visual attention (Ling and Carrasco, 2006). We examined if and how auditory contrast sensitivity varied as a function of attentional load, the difficulty of a competing visual task, and how such effects compared to those found for the influences of attention on visual processing. In our paradigm, subjects listened to two sequential white noise stimuli, one of which was amplitude modulated. Subjects reported which interval contained the amplitude modulated auditory stimulus. At the same time a sequence of 5 letters was presented, in an rsvp stream at central fixation, for each interval. Subjects judged which interval contained the visual target. For a given block of trials, subjects judged which interval contained white letters (easy visual task) or, in a separate block of trials, which interval had more target letters ‘A’ (difficult visual task). We found that auditory thresholds were lower for the easy compared to the difficult visual task and that the shift in the auditory contrast response function was reminiscent of a contrast gain mechanism for visual contrast. Importantly, we found that the effects of crossmodal attention on the auditory contrast response function diminished with practice.

Cross-modal selective attention effects on steady-state visual evoked potentials (SSVEPs)

Cross-modal selective attention effects on steady-state visual evoked potentials (SSVEPs)

What Happens in Between? Human Oscillatory Brain Activity Related to Crossmodal Spatial Cueing

Previous studies investigated the effects of crossmodal spatial attention by comparing the responses to validly versus invalidly cued target stimuli. Dynamics of cortical rhythms in the time interval between cue and target might contribute to cue effects on performance. Here, we studied the influence of spatial attention on ongoing oscillatory brain activity in the interval between cue and target onset. In a first experiment, subjects underwent periods of tactile stimulation (cue) followed by visual stimulation (target) in a spatial cueing task as well as tactile stimulation as a control. In a second experiment, cue validity was modified to be 50%, 75%, or else 25%, to separate effects of exogenous shifts of attention caused by tactile stimuli from that of endogenous shifts. Tactile stimuli produced: 1) a stronger lateralization of the sensorimotor beta-rhythm rebound (15–22 Hz) after tactile stimuli serving as cues versus not serving as cues; 2) a suppression of the occipital alpha-rhythm (7–13 Hz) appearing only in the cueing task (this suppression was stronger contralateral to the endogenously attended side and was predictive of behavioral success); 3) an increase of prefrontal gamma-activity (25–35 Hz) specifically in the cueing task. We measured cue-related modulations of cortical rhythms which may accompany crossmodal spatial attention, expectation or decision, and therefore contribute to cue validity effects. The clearly lateralized alpha suppression after tactile cues in our data indicates its dependence on endogenous rather than exogenous shifts of visuo-spatial attention following a cue independent of its modality.

Crossmodal effect with rubber hand illusion and gamma‐band activity

The integration of multimodal stimuli has been regarded as important for the promotion of adaptive behavior. Although recent work has identified brain areas that respond to multimodal stimuli, the temporal features are not clear yet. Earlier event-related potential studies revealed crossmodal attention effects, but did not focus on mechanisms underlying crossmodal integration. Here, electroencephalography (EEG) activity in the gamma band was considered as a correlate of multimodal integration. Participants localized a tactile stimulus on their fingers while seeing visual stimuli on rubber hands with the same posture as their hands. EEG analyses using wavelet transform suggested that interelectrode phase synchrony in the gamma-band range (40-50 Hz) was related to behavioral indices of the intermodal illusion under consideration. The findings suggest a role of high-frequency oscillations in the integrative processing of stimuli across modalities.

Crossmodal attention effects on brain responses to different stimulus classes

BackgroundAttending to a point in space in one modality may facilitate processing to information from the same region in another modality. The involvement of sensory-specific cortical areas in intramodal and crossmodal selective spatial attention can be assessed with event-related brain potentials (ERPs).ERPs were recorded in two groups of young participants (each n = 11). Stimulus sequences comprised visual standard stimuli (p = 0.4, a white square), visual deviant stimuli (p = 0.05, a white square with small black rectangle) and visual novel stimuli (p = 0.05, different multicolored checkerboards) as well as auditory standard (p = 0.4, 800 Hz tone), deviant (p = 0.05, 900 Hz tone), and novel (p = 0.05, random combination of three sine-wave tones) stimuli, occurring in random order at locations 30 degrees left and right of a fixation point. The "auditory group" of participants attended either to the left or to the right speaker in order to respond to the infrequent auditory deviants at that location by a speeded button press. Visual stimuli were irrelevant for this group. The "visual group" had the analogue task for the visual modality. For these participants auditory stimuli were irrelevant throughout the experiment.ResultsERPs showed a typical enhancement of early sensory specific components by intramodal spatial attention (visual group: visual P1 and N1; auditory group: auditory Nd). Crossmodal spatial attention effects included a modulation of the Nd to auditory standards in the visual group and a modulation of the P1 to visual novels and N1 for visual standards for the auditory group. Similar to previous studies crossmodal spatial attention effects on visual standard and novel stimuli also included a frontocentral positivity in the 200–400 ms range that was not seen for intramodal spatial visual attention suggesting involvement of later supramodal areas.ConclusionThese findings are consistent with an action of crossmodal spatial attention on early, sensory specific processing stages.

An event‐related potential study of supramodal attentional control and crossmodal attention effects

We conducted two audiovisual experiments to determine whether event-related potential (ERP) components elicited by attention-directing cues reflect supramodal attentional control. Symbolic visual cues were used to direct attention prior to auditory targets in Experiment 1, and symbolic auditory cues were used to direct attention prior to visual targets in Experiment 2. Different patterns of cue ERPs were found in the two experiments. A frontal negativity called the ADAN was absent in Experiment 2, which indicates that this component does not reflect supramodal attentional control. A posterior positivity called the LDAP was observed in both experiments but was focused more posteriorly over the occipital scalp in Experiment 2. This component appears to reflect multiple processes, including visual processes involved in location marking and target preparation as well as supramodal processes involved in attentional control.

Attending to visual or auditory motion affects perception within and across modalities: An event-related potential study

The present event-related potential (ERP) study examined the role of dynamic features in multisensory binding. It was tested whether endogenous attention to the direction of motion affects processing of visual and auditory stimuli within and across modalities. Human participants perceived horizontally moving dot patterns and sounds that were presented either continuously (standards) or briefly interrupted (infrequent deviants). Their task was to detect deviants moving in a particular direction within a primary modality, but to detect all deviants irrespective of their motion direction within the secondary modality. Attending to the direction of visual motion resulted in a broad selection negativity (SN) starting at about 200 ms post-stimulus onset, and attending to the direction of auditory motion resulted in a positive difference wave at 150 ms that was followed by a broad negativity starting at about 200 ms (unimodal effects). Moreover, dot patterns moving in a direction that was attended within audition were detected faster and more accurately than oppositely moving stimuli and elicited a cross-modal SN wave. Corresponding cross-modal behavioural and ERP results were obtained for sounds moving in a direction that was attended within vision. Unimodal and cross-modal ERP attention effects partially differed in their scalp topography. The present study shows that dynamic features (direction of motion) may be used to link input across modalities and demonstrates for the first time that these multisensory interactions take place as early as about 200 ms after stimulus onset.

Attending to visual or auditory motion affects perception within and across modalities: an event‐related potential study

The present event-related potential (ERP) study examined the role of dynamic features in multisensory binding. It was tested whether endogenous attention to the direction of motion affects processing of visual and auditory stimuli within and across modalities. Human participants perceived horizontally moving dot patterns and sounds that were presented either continuously (standards) or briefly interrupted (infrequent deviants). Their task was to detect deviants moving in a particular direction within a primary modality, but to detect all deviants irrespective of their motion direction within the secondary modality. Attending to the direction of visual motion resulted in a broad selection negativity (SN) starting at about 200 ms post-stimulus onset, and attending to the direction of auditory motion resulted in a positive difference wave at 150 ms that was followed by a broad negativity starting at about 200 ms (unimodal effects). Moreover, dot patterns moving in a direction that was attended within audition were detected faster and more accurately than oppositely moving stimuli and elicited a cross-modal SN wave. Corresponding cross-modal behavioural and ERP results were obtained for sounds moving in a direction that was attended within vision. Unimodal and cross-modal ERP attention effects partially differed in their scalp topography. The present study shows that dynamic features (direction of motion) may be used to link input across modalities and demonstrates for the first time that these multisensory interactions take place as early as about 200 ms after stimulus onset.

Cross-modal attention effects vary across human visual cortex

Cross-modal attention effects vary across human visual cortex

Crossmodal attention between vision and touch in temporal order judgment task

Four experiments investigated the effects of cross-modal attention between vision and touch in temporal order judgment tasks combined with spatial cueing paradigm. In Experiment 1, two vibrotactile stimuli with simultaneous or successive onsets were presented bimanually to the left and right index fingers and participants were asked to judge the temporal order of the two stimuli. The tactile stimuli were preceded by a spatially uninformative visual cue. Results indicated that shift of spatial attention yielded by visual cueing resulted in the modulation of accuracy of the subsequent tactile temporal order judgment. However, this cueing effect disappeared when participants judged simultaneity of the two stimuli, instead of their temporal order (Experiment 2) or when the cue lead time between the visual cue and the stimuli was relatively long (Experiment 3). Experiment 4 replicated an effect of crossmodal attention on the direction of visual illusory line motion induced by a somatosensory cue (Shimojo, Miyauchi, & Hikosaka, 1997). These results demonstrate that substantial crossmodal links exist between vision and touch for covert exogenous orienting of attention.

Crossmodal links in endogenous and exogenous spatial attention: evidence from event-related brain potential studies

The adaptive control of behaviour in response to relevant external objects and events often requires the selection of information delivered by different sensory systems, but from the same region in external space. This can be facilitated by crossmodal links in the attentional processing of information across sensory modalities. Results from recent event-related potential (ERP) studies are reviewed that investigated mechanisms underlying such crossmodal links in spatial attention between vision, audition and touch. Crossmodal attention effects were observed for early modality-specific visual, auditory, and somatosensory ERP components, indicating that crossmodal links in spatial attention affect sensory-perceptual processes within modality-specific cortical regions. ERP modulations prior to target events but sensitive to the direction of an attentional shift were remarkably similar during anticipatory covert shifts of visual, auditory, or tactile attention. These results suggest that such attentional shifts are mediated by supramodal frontoparietal control mechanisms. Finally, ERP evidence is reviewed suggesting that effects of crossmodal links in endogenous (voluntary) as well as exogenous (involuntary) spatial attention are mediated by a representations of external space which are updated across postural changes.

Cross-modal exogenous attention and distance effects in vision and hearing

In the present study we investigated cross-modal orienting in vision and hearing by using a cueing task with four different horizontal locations. Our main interest concerned cue–target distance effects, which might further our insight in the characteristics of cross-modal spatial attention mechanisms. A very consistent pattern was observed for both the unimodal (cue and target were both visual or auditory) and the cross-modal conditions (cue and target from different modalities). RTs to valid trials were faster than for invalid trials, and, most interestingly, there was a distance effect: RTs increased with greater cue–target distance. This applied to detection of visual targets and to localisation of both visual and auditory targets. The time interval between cue and target was also varied. Surprisingly, there was no indication of inhibition of return even with the longest cue–target intervals. In order to assess the role of endogenous (strategic) factors in exogenous spatial attention we increased in two additional experiments the cue validity from 25% to 80%. This appeared to have no large influence on the cueing pattern in both the detection and localisation tasks. Currently, it is assumed that spatial attention is organised in multiple strongly linked modality-specific systems. The foregoing results are discussed with respect to this supposed organisation.

Cross-modal exogenous attention and distance effects in vision and hearing

Cross-modal exogenous attention and distance effects in vision and hearing

Multisensory integration and crossmodal attention effects in the human brain.

Macaluso et al. ([1][1]) provided functional magnetic resonance imaging (fMRI) evidence for multisensory processing in the human brain. In their study, a light presented in the right visual field produced a larger neural response in the left fusiform gyrus, a modality-specific area of visual cortex

Involuntary listening aids seeing: evidence from human electrophysiology.

It is well known that sensory events of one modality can influence judgments of sensory events in other modalities. For example, people respond more quickly to a target appearing at the location of a previous cue than to a target appearing at another location, even when the two stimuli are from different modalities. Such cross-modal interactions suggest that involuntary spatial attention mechanisms are not entirely modality-specific. In the present study, event-related brain potentials (ERPs) were recorded to elucidate the neural basis and timing of involuntary, cross-modal spatial attention effects. We found that orienting spatial attention to an irrelevant sound modulates the ERP to a subsequent visual target over modality-specific, extrastriate visual cortex, but only after the initial stages of sensory processing are completed. These findings are consistent with the proposal that involuntary spatial attention orienting to auditory and visual stimuli involves shared, or at least linked, brain mechanisms.