Exogenous Attention Tasks Research Articles

Attentional development is altered in toddlers with congenital heart disease.

Congenital Heart Disease (CHD) is the most common congenital abnormality. Survival rates are over 90%, however infants with CHD remain at high risk of attention and executive function impairments. These abilities are difficult to assess in toddlers because clinical assessments rely on language abilities which are commonly delayed in CHD. Our aim was to characterise visual attention in toddlers with CHD compared to controls and identify associations with parent-rated effortful control. Thirty toddlers with CHD (19 male, median (IQR) age at assessment 22.2 (22-23.1) months) and 66 controls from the developing human connectome project (36 male, age at assessment 22 (21.5-23.8) months) using eye-tracking tasks designed to assess multiple components of visual attention. Analyses of co-variance and regressions were used to identify differences between groups and relationships between gaze behaviours and parent-rated effortful control. Toddlers with CHD were less accurate when switching behaviours (set-shifting) [median (IQR) 79%, (28-100)] compared to controls [100% (86-100), pFDR=0.032], with worse accuracy associated with lower parent-rated effortful control in CHD but not controls (interaction pFDR=0.028). Reaction times were slower during selective [CHD 1243ms (986-1786), controls 1065ms (0851-1397), pFDR<0.001] and exogenous attention tasks [CHD 312ms (279-358), control 289 (249-331), (pFDR=0.032) and endogenous attention was less mature (prolonged looks at facial stimuli CHD 670ms (518-885), control 500ms (250-625), (pFDR=0.006). These results were unrelated to differences in cognition or socioeconomic status. In contrast, the allocation of attentional resources was preserved in CHD. We identified a profile of altered attention and early executive functioning development in CHD. Eye-tracking may provide clinically feasible, early objective measures of attention and executive function development in CHD.

Intracortical recordings reveal vision-to-action cortical gradients driving human exogenous attention

Exogenous attention, the process that makes external salient stimuli pop-out of a visual scene, is essential for survival. How attention-capturing events modulate human brain processing remains unclear. Here we show how the psychological construct of exogenous attention gradually emerges over large-scale gradients in the human cortex, by analyzing activity from 1,403 intracortical contacts implanted in 28 individuals, while they performed an exogenous attention task. The timing, location and task-relevance of attentional events defined a spatiotemporal gradient of three neural clusters, which mapped onto cortical gradients and presented a hierarchy of timescales. Visual attributes modulated neural activity at one end of the gradient, while at the other end it reflected the upcoming response timing, with attentional effects occurring at the intersection of visual and response signals. These findings challenge multi-step models of attention, and suggest that frontoparietal networks, which process sequential stimuli as separate events sharing the same location, drive exogenous attention phenomena such as inhibition of return.

Tinnitus Affects Endogenous But Not Exogenous Auditory Attention Orienting.

Previous studies have demonstrated that people with tinnitus show attention dysfunctions. In this study, we investigated the influence of tinnitus on attention orienting, especially whether the ability of attention orienting could be modulated by the degree of tinnitus. Fifty-nine and 54 unilateral tinnitus participants were included in Experiment 1 and Experiment 2, respectively. All participants reported subjective tinnitus for at least 3 months and were divided into a mild tinnitus group (Tinnitus Handicap Inventory [THI] < 37) or a moderate to severe tinnitus group (THI ≥ 37) according to the THI score. An auditory exogenous attention task and an auditory endogenous attention task were adopted. In the exogenous task, a target sound following a cue sound was presented on either the left or right side. Participants were required to discriminate whether the target was pure tone or white noise. In the endogenous task, participants were required to pay attention to the stimuli on one side and judge the pitch of a target sound. Mixed-design analyses of variance were conducted for the mean reaction times and accuracy across the experimental conditions. Our results showed that in the endogenous attention task, compared with the mild tinnitus group, moderate to severe tinnitus participants had better performance for stimuli presented on the tinnitus side but not on the nontinnitus side. In contrast, in the exogenous attention task, no differences were found between mild and moderate to severe tinnitus groups. The results suggest that the degree of tinnitus influences the performance of auditory endogenous attention but not auditory exogenous attention orienting.

Parietal but not temporoparietal alpha-tACS modulates endogenous visuospatial attention

Visuospatial attention can either be voluntarily directed (endogenous/top-down attention) or automatically triggered (exogenous/bottom-up attention). Recent research showed that dorsal parietal transcranial alternating current stimulation (tACS) at alpha frequency modulates the spatial attentional bias in an endogenous but not in an exogenous visuospatial attention task. Yet, the reason for this task-specificity remains unexplored. Here, we tested whether this dissociation relates to the proposed differential role of the dorsal attention network (DAN) and ventral attention network (VAN) in endogenous and exogenous attention processes respectively. To that aim, we targeted the left and right dorsal parietal node of the DAN, as well as the left and right ventral temporoparietal node of the VAN using tACS at the individual alpha frequency. Every participant completed all four stimulation conditions and a sham condition in five separate sessions. During tACS, we assessed the behavioral visuospatial attention bias via an endogenous and exogenous visuospatial attention task. Additionally, we measured offline alpha power immediately before and after tACS using electroencephalography (EEG). The behavioral data revealed an effect of tACS on the endogenous but not exogenous attention bias, with a greater leftward bias during (sham-corrected) left than right hemispheric stimulation. In line with our hypothesis, this effect was brain area-specific, i.e., present for dorsal parietal but not ventral temporoparietal tACS. However, contrary to our expectations, there was no effect of ventral temporoparietal tACS on the exogenous visuospatial attention bias. Hence, no double dissociation between the two targeted attention networks. There was no effect of either tACS condition on offline alpha power. Our behavioral data reveal that dorsal parietal but not ventral temporoparietal alpha oscillations steer endogenous visuospatial attention. This brain-area specific tACS effect matches the previously proposed dissociation between the DAN and VAN and, by showing that the spatial attention bias effect does not generalize to any lateral posterior tACS montage, renders lateral cutaneous and retinal effects for the spatial attention bias in the dorsal parietal condition unlikely. Yet the absence of tACS effects on the exogenous attention task suggests that ventral temporoparietal alpha oscillations are not functionally relevant for exogenous visuospatial attention. We discuss the potential implications of this finding in the context of an emerging theory on the role of the ventral temporoparietal node.

Exploration of Exogenous Attention to Disgust and Fear Pictures with Different Spatial Frequencies Through Event-related Potentials

The study of the effects of fear and disgust on the capture of automatic attention is gaining interest. Most findings reveal a more efficient capture of exogenous attention by disgust than by fear stimuli, although the underlying mechanisms are not completely understood. The manipulation of their spatial frequency may provide new insight that may contribute to clarify this issue. The present study aimed to explore differential processing of disgust and fear scenes containing only low spatial frequencies (LSF) or all spatial frequencies (intact) presented as distractors in an exogenous attention task. Event-related potentials (ERPs) and behavioral responses were recorded as dependent variables from forty participants (29 women). The results showed that disgust and fear distractors captured exogenous attention equally early, as indicated by the augmented amplitude of the N2p, and later disgust distractors are the ones eliciting the highest amplitude of the LPP component. While in an initial stage, both stimuli seem to have similar preferential access to further processing allowing fast responding in both cases, disgust is more deeply processed at a later stage probably facilitating its examination. These findings suggest that exploring the temporal course of processing is relevant for the understanding of the differential capture of exogenous attention by disgust and fear distractors.

Lateralized alpha activity and slow potential shifts over visual cortex track the time course of both endogenous and exogenous orienting of attention

Spatial attention can be oriented endogenously, based on current task goals, or exogenously, triggered by salient events in the environment. Based upon literature demonstrating differences in the time course and neural substrates of each type of orienting, these two attention systems are often treated as fundamentally distinct. However, recent studies suggest that rhythmic neural activity in the alpha band (8–13 Hz) and slow waves in the event-related potential (ERP) may emerge over parietal-occipital cortex following both endogenous and exogenous attention cues. To assess whether these neural changes index common processes of spatial attention, we conducted two within-subject experiments varying the two main dimensions over which endogenous and exogenous attention tasks typically differ: cue informativity (spatially predictive vs. non-predictive) and cue format (centrally vs. peripherally presented). This task design allowed us to tease apart neural changes related to top-down goals and those driven by the reflexive orienting of spatial attention, and examine their interactions in a novel hybrid cross-modal attention task. Our data demonstrate that both central and peripheral cues elicit lateralized ERPs over parietal-occipital cortex, though at different points in time, consistent with these ERPs reflecting the orienting of spatial attention. Lateralized alpha activity was also present across all tasks, emerging rapidly for peripheral cues and sustaining longer for spatially informative cues. Overall, these data indicate that distinct slow-wave ERPs index the spatial orienting of endogenous and exogenous attention, while lateralized alpha activity represents a common signature of visual-cortical biasing in anticipation of potential targets across both types of attention.

Quasi-Randomized Trial of Contact With Nature and Effects on Attention in Children.

Children today spend less time in nature than previous generations and there is concern that this shift negatively impacts children’s cognitive abilities, particularly their ability to direct their attention. Theories, such as the Attention Restoration Theory (ART), suggest that contact with nature may replenish endogenous attention (e.g., directed, voluntary attention). There is a lack of rigorous research on how contact with nature is associated with attentional performance in children. This study employed a quasi-experimental design and included a sample of typically developing children to investigate performance on computerized endogenous and exogenous attention tasks before and after exposure to one of two interventions – a 30-min walk in either an urban (n = 30) or natural (forested, n = 30) environment. The two experimental groups were equivalent with regard to sex ratio, age, IQ, and connectedness to nature. Attention was assessed using the Combined Attention Systems Test (CAST), a state-of-the-art assessment tool designed to evaluate exogenous and endogenous attention characteristics. Bayesian hierarchical modeling of both response time (RT) and error rate (ER) was employed to evaluate the fixed effect of attentional measures and interactions with session and group. Consistent with predictions of ART, results support credible effects of the nature intervention on two measures of endogenous attention: Alerting RT: d = 0.85 (95% CI: 0.21–1.8), Orienting ER: d = 1.45 (95% CI: 0.17–7.18), but not on any of the measures of exogenous attention.Clinical Trial Registration: https://www.isrctn.com/, identifier ISRCTN17762011.

Does oculomotor readiness mediate exogenous capture of visual attention?

The oculomotor readiness hypothesis makes 2 predictions: Shifts in covert attention are accompanied by preparedness to move one's eyes to the attended region, and preparedness to move one's eyes to a region in space is accompanied by a shift in covert attention to the prepared location. Both predictions have been disconfirmed using an endogenous attention task. In the 2 experiments presented here, the same 2 predictions were tested using an exogenous attention task. It was found that participants experienced covert capture without accompanying oculomotor activation and experienced oculomotor activation without accompanying covert capture. While under everyday conditions the overt and covert orienting systems may be strongly linked, apparently they can nonetheless operate with a high degree of independence from one another. (PsycINFO Database Record

Differential Frontal Activation during Exogenous and Endogenous Orientation of Visuospatial Attention

Aims: The aim was to measure the prefrontal cortical activity involved in shifting spatial attention to visual stimuli in the left or right visual field using near-infrared spectroscopy. Methods: Eleven participants performed a simple vigilance task, an endogenous attention task and an exogenous attention task. In the endogenous task, the left or the right side of the center diamond brightened, indicating the side for subsequent target appearance (controlled shift of attention). In the exogenous task, the peripheral squares brightened, indicating the appearance of target in those squares (reflexive shift of attention). Results: Stimuli at validly cued locations were responded to faster than stimuli at invalidly cued locations. Increases in oxyhemoglobin (oxy-Hb) were observed in the right prefrontal cortex throughout the 3 tasks, and in the left prefrontal cortex during the vigilance and the exogenous tasks. In the exogenous task, marked decreases in oxy-Hb were observed in the bilateral ventrolateral prefrontal cortex. Conclusions: These results suggest that the left and the right prefrontal cortices mediate distinct cognitive processes during the performance of visuospatial attentional tasks.

Discussion

Schizophrenic, affective disorder, and normal subjects performed tasks involving exogenous (automatic) and endogenous (voluntary) attention. In the exogenous attention task, schizophrenic subjects demonstrated a greater benefit in response time than did normal subjects. In the endogenous attention task, however, schizophrenic subjects showed a smaller benefit in response time than did normal subjects. These results are consistent with a model of schizophrenia that predicts a deficit in voluntary (endogenous) control, and a disinhibition and therefore enhancement of the automatic (exogenous) processes of spatial selective attention. Affective disorder subjects did not demonstrate a greater benefit in response time than normal subjects in the exogenous attention task, but did show a smaller benefit in response time than normal subjects in the endogenous attention task. The somewhat similar pattern of behavior of schizophrenic and affective disorder subjects suggests that abnormal spatial selective attentional processes may not be specific to schizophrenia.

Spatial selective attention in schizophrenic, affective disorder, and normal subjects

Schizophrenic, affective disorder, and normal subjects performed tasks involving exogenous (automatic) and endogenous (voluntary) attention. In the exogenous attention task, schizophrenic subjects demonstrated a greater benefit in response time than did normal subjects. In the endogenous attention task, however, schizophrenic subjects showed a smaller benefit in response time than did normal subjects. These results are consistent with a model of schizophrenia that predicts a deficit in voluntary (endogenous) control, and a disinhibition and therefore enhancement of the automatic (exogenous) processes of spatial selective attention. Affective disorder subjects did not demonstrate a greater benefit in response time than normal subjects in the exogenous attention task, but did show a smaller benefit in response time than normal subjects in the endogenous attention task. The somewhat similar pattern of behavior of schizophrenic and affective disorder subjects suggests that abnormal spatial selective attentional processes may not be specific to schizophrenia.