Multisensory Integration and Exogenous Spatial Attention: A Time-window-of-integration Analysis

2019 ◽  
Vol 31 (5) ◽  
pp. 699-710
Author(s):  
Adele Diederich ◽  
Hans Colonius

Although it is well documented that occurrence of an irrelevant and nonpredictive sound facilitates motor responses to a subsequent target light appearing nearby, the cause of this “exogenous spatial cuing effect” has been under discussion. On the one hand, it has been postulated to be the result of a shift of visual spatial attention possibly triggered by parietal and/or cortical supramodal “attention” structures. On the other hand, the effect has been considered to be due to multisensory integration based on the activation of multisensory convergence structures in the brain. Recent RT experiments have suggested that multisensory integration and exogenous spatial cuing differ in their temporal profiles of facilitation: When the nontarget occurs 100–200 msec before the target, facilitation is likely driven by crossmodal exogenous spatial attention, whereas multisensory integration effects are still seen when target and nontarget are presented nearly simultaneously. Here, we develop an extension of the time-window-of-integration model that combines both mechanisms within the same formal framework. The model is illustrated by fitting it to data from a focused attention task with a visual target and an auditory nontarget presented at horizontally or vertically varying positions. Results show that both spatial cuing and multisensory integration may coexist in a single trial in bringing about the crossmodal facilitation of RT effects. Moreover, the formal analysis via time window of integration allows to predict and quantify the contribution of either mechanism as they occur across different spatiotemporal conditions.

2004 ◽  
Vol 16 (6) ◽  
pp. 1000-1009 ◽  
Author(s):  
Hans Colonius ◽  
Adele Diederich

Saccadic reaction time to visual targets tends to be faster when stimuli from another modality (in particular, audition and touch) are presented in close temporal or spatial proximity even when subjects are instructed to ignore the accessory input (focused attention task). Multisensory interaction effects measured in neural structures involved in saccade generation (in particular, the superior colliculus) have demonstrated a similar spatio-temporal dependence. Neural network models of multisensory spatial integration have been shown to generate convergence of the visual, auditory, and tactile reference frames and the sensorimotor coordinate transformations necessary for coordinated head and eye movements. However, because these models do not capture the temporal coincidences critical for multisensory integration to occur, they cannot easily predict multisensory effects observed in behavioral data such as saccadic reaction times. This article proposes a quantitative stochastic framework, the time-window-of-integration model, to account for the temporal rules of multisensory integration. Saccadic responses collected from a visual–tactile focused attention task are shown to be consistent with the time-window-of-integration model predictions.


2001 ◽  
Vol 15 (1) ◽  
pp. 22-34 ◽  
Author(s):  
D.H. de Koning ◽  
J.C. Woestenburg ◽  
M. Elton

Migraineurs with and without aura (MWAs and MWOAs) as well as controls were measured twice with an interval of 7 days. The first session of recordings and tests for migraineurs was held about 7 hours after a migraine attack. We hypothesized that electrophysiological changes in the posterior cerebral cortex related to visual spatial attention are influenced by the level of arousal in migraineurs with aura, and that this varies over the course of time. ERPs related to the active visual attention task manifested significant differences between controls and both types of migraine sufferers for the N200, suggesting a common pathophysiological mechanism for migraineurs. Furthermore, migraineurs without aura (MWOAs) showed a significant enhancement for the N200 at the second session, indicating the relevance of time of measurement within migraine studies. Finally, migraineurs with aura (MWAs) showed significantly enhanced P240 and P300 components at central and parietal cortical sites compared to MWOAs and controls, which seemed to be maintained over both sessions and could be indicative of increased noradrenergic activity in MWAs.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Tao Yao ◽  
Madhura Ketkar ◽  
Stefan Treue ◽  
B Suresh Krishna

Maintaining attention at a task-relevant spatial location while making eye-movements necessitates a rapid, saccade-synchronized shift of attentional modulation from the neuronal population representing the task-relevant location before the saccade to the one representing it after the saccade. Currently, the precise time at which spatial attention becomes fully allocated to the task-relevant location after the saccade remains unclear. Using a fine-grained temporal analysis of human peri-saccadic detection performance in an attention task, we show that spatial attention is fully available at the task-relevant location within 30 milliseconds after the saccade. Subjects tracked the attentional target veridically throughout our task: i.e. they almost never responded to non-target stimuli. Spatial attention and saccadic processing therefore co-ordinate well to ensure that relevant locations are attentionally enhanced soon after the beginning of each eye fixation.


Perception ◽  
2016 ◽  
Vol 46 (1) ◽  
pp. 6-17 ◽  
Author(s):  
N. Van der Stoep ◽  
S. Van der Stigchel ◽  
T. C. W. Nijboer ◽  
C. Spence

Multisensory integration (MSI) and exogenous spatial attention can both speedup responses to perceptual events. Recently, it has been shown that audiovisual integration at exogenously attended locations is reduced relative to unattended locations. This effect was observed at short cue-target intervals (200–250 ms). At longer intervals, however, the initial benefits of exogenous shifts of spatial attention at the cued location are often replaced by response time (RT) costs (also known as Inhibition of Return, IOR). Given these opposing cueing effects at shorter versus longer intervals, we decided to investigate whether MSI would also be affected by IOR. Uninformative exogenous visual spatial cues were presented between 350 and 450 ms prior to the onset of auditory, visual, and audiovisual targets. As expected, IOR was observed for visual targets (invalid cue RT < valid cue RT). For auditory and audiovisual targets, neither IOR nor any spatial cueing effects were observed. The amount of relative multisensory response enhancement and race model inequality violation was larger for uncued as compared with cued locations indicating that IOR reduces MSI. The results are discussed in the context of changes in unisensory signal strength at cued as compared with uncued locations.


2005 ◽  
Vol 68 (2) ◽  
pp. 121-134 ◽  
Author(s):  
Joel Ramirez ◽  
Marie Bomba ◽  
Anthony Singhal ◽  
Barry Fowler

1999 ◽  
Vol 354 (1387) ◽  
pp. 1135-1144 ◽  
Author(s):  
Scott Makeig ◽  
Marissa Westerfield ◽  
Jeanne Townsend ◽  
Tzyy-Ping Jung ◽  
Eric Courchesne ◽  
...  

Spatial visual attention modulates the first negative–going deflection in the human averaged event–related potential (ERP) in response to visual target and non–target stimuli (the N1 complex). Here we demonstrate a decomposition of N1 into functionally independent subcomponents with functionally distinct relations to task and stimulus conditions. ERPs were collected from 20 subjects in response to visual target and non–target stimuli presented at five attended and non–attended screen locations. Independent component analysis, a new method for blind source separation, was trained simultaneously on 500 ms grand average responses from all 25 stimulus–attention conditions and decomposed the non–target N1 complexes into five spatially fixed, temporally independent and physiologically plausible components. Activity of an early, laterally symmetrical component pair (N1a R and N1a L ) was evoked by the left and right visual field stimuli, respectively. Component N1a R peaked ca. 9 ms earlier than N1a L . Central stimuli evoked both components with the same peak latency difference, producing a bilateral scalp distribution. The amplitudes of these components were not reliably augmented by spatial attention. Stimuli in the right visual field evoked activity in a spatio–temporally overlapping bilateral component (N1b) that peaked at ca. 180 ms and was strongly enhanced by attention. Stimuli presented at unattended locations evoked a fourth component (P2a) peaking near 240 ms. A fifth component (P3f) was evoked only by targets presented in either visual field. The distinct response patterns of these components across the array of stimulus and attention conditions suggest that they reflect activity in functionally independent brain systems involved in processing attended and unattended visuospatial events.


2018 ◽  
Author(s):  
Marjolein van der Waal ◽  
Inez Wijnands ◽  
Jason Farquhar

Behavioural effects of prism adaptation in healthy subjects and neglect patients suggest a link between prism adaptation and spatial attention. A recent study found an effect of prism adaptation on several EEG correlates of spatial attention, but for two other correlates (the P3 component of the oddball ERP and alpha lateralization), the relationship remained unclear. In the current experiment, 10 healthy subjects performed a visual spatial attention task which was optimized for eliciting these two brain signals. This task was performed before and after adaptation to prism glasses with a leftward optical deviation. While prism adaptation induced a rightward bias on a pointing task, there was no effect of adaptation on behavioural performance on the spatial attention task. Moreover, the P3 component of the ERP and alpha lateralization were not influenced by prism adaptation. Together, these results show that some EEG correlates of visual spatial attention remain unchanged after prism adaptation, a finding which has its implications for current models of the neurocognitive mechanisms behind prism adaptation.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Zongya Zhao ◽  
Chang Wang

Previous studies have shown that the neural mechanisms underlying visual spatial attention rely on top-down control information from the frontal and parietal cortexes, which ultimately amplifies sensory processing of stimulus occurred at the attended location relative to those at unattended location. However, the modulations of effective brain networks in response to stimulus at attended and unattended location are not yet clear. In present study, we collected event-related potentials (ERPs) from 15 subjects during a visual spatial attention task, and a partial directed coherence (PDC) method was used to construct alpha-band effective brain networks of two conditions (targets at attended and nontargets at unattended location). Flow gain mapping, effective connectivity pattern, and graph measures including clustering coefficient (C), characteristic path length (L), global efficiency (Eglobal), and local efficiency (Elocal) were compared between two conditions. Flow gain mapping showed that the frontal region seemed to serve as the main source of information transmission in response to targets at attended location while the parietal region served as the main source in nontarget condition. Effective connectivity pattern indicated that in response to targets, there existed obvious top-down connections from the frontal, temporal, and parietal cortexes to the visual cortex compared with in response to nontargets. Graph theory analysis was used to quantify the topographical properties of the brain networks, and results revealed that in response to targets, the brain networks were characterized by significantly smaller characteristic path length and larger global efficiency than in response to nontargets. Our findings suggested that smaller characteristic path length and larger global efficiency could facilitate global integration of information and provide a substrate for more efficient perceptual processing of targets at attended location compared with processing of nontargets at ignored location, which revealed the neural mechanisms underlying visual spatial attention from the perspective of effective brain networks and graph theory for the first time and opened new vistas to interpret a cognitive process.


Author(s):  
Shuo Zhao ◽  
Chunlin Li ◽  
Jinglong Wu ◽  
Hongbin Han ◽  
Dehua Chui

Visual orienting attention is best studied using visual cues. Spatial and temporal attention have been compared using brain-imaging data. This chapter’s authors developed a visual orienting attention tool to compare auditory when a visual target was presented. They also designed a control task in which subjects had to click on the response key consistent with a simultaneous spatial task. The effect of clicking the response key was removed by subtracting the brain activations elicited by clicking the response key from the results of the visual voluntary attention task. The authors then measured brain activity in sixteen healthy volunteers using functional magnetic resonance imaging (Coull, Frith, Büchel & Nobre, 2000). In the task, visual spatial attention was manipulated by a visual cue, and participants were told to ignore the auditory stimulus. A neutral task was also performed, in which a neutral cue was used. Symbolic central cues oriented subjects to spatial location only (Coull & Nobre, 1998) or gave no information about spatial location. Subjects were also scanned during a resting baseline condition in which they clicked the reaction key ten times. The reaction time for spatial location attention was faster than that without an auditory stimulus. Brain-imaging data showed that the inferior parietal lobe (IPL) and anterior cingulated cortex (ACC) were activated in the visual-spatial attention task and that the activation was enhanced during the task with the auditory stimulus.


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