Similar to its temporal counterpart visual temporal attention, these attention modules have been widely implemented in video analytics in computer vision to provide enhanced performance and human interpretable explanation[1][2][3] of deep learning models.
According to the V1 Saliency Hypothesis, the human primary visual cortex plays a critical role for such an exogenous attentional guidance.
In Posner's cueing paradigm,[4] the task was to detect a target that could be presented in one of two locations and respond as quickly as possible.
To investigate covert attention, it is necessary to ensure that observer's eyes remain fixated at one location throughout the task.
This ensures that covert spatial attention is being measured and the effects are not due to overt eye movements.
This was demonstrated by valid cues improving the identification of targets relative to the invalid and neutral conditions.
[13][14] For example, it was found that when attention was allocated to detecting a flickering dot (spatial probe), this increased the likelihood of identifying nearby letters.
This supports findings that show attention can be distributed both over a large area of the visual field and also function in a focused mode.
[18] In support of this analogy, research has shown that there is an inverse relationship between the size of the attentional focus and the efficiency of processing within the boundaries of a zoom-lens.
For example, Hughes and Zimba [21] conducted a similar experiment, using a highly distributed visual array and did not use boxes to mark the potential locations of the target.
A broader gradient may be adopted when there is an empty display, as attention can spread and is only restricted by hemifield borders.
[15] In addition, it has been demonstrated that observers are unable to ignore stimuli presented in areas situated between two cued locations.
Hemineglect refers to the inability of patients with unilateral brain damage to detect objects in the side of space contralateral to the lesion (contralesional); i.e. damage to the right cerebral hemisphere resulting in neglect of objects on the left side of space,[27] and is characterized by hemispheric asymmetry.
[27] It has been proposed that the right parietal lobes are comparatively more responsible for the allocation of spatial attention, therefore damage to this hemisphere often produces more severe effects.
Patients with neglect will perform similarly when reproducing mental images of familiar places and objects.
During this task, patients are required to cancel out (cross out) all of the objects in a cluttered display (e.g. lines, geometric shapes, letters, etc.).
In addition, those patients who may be severely affected tend to fail in detecting their errors on visual inspection.
[10] Analogous to neglect, extinction affects the contralesional visuospatial field in majority of patients with unilateral damage.
[10] Computed tomography (CT) studies have demonstrated that the inferior parietal lobule in the right hemisphere is the most frequently damaged in patients with severe neglect.
Disruption to spatial orienting, as seen in hemineglect, suggests that patients with damage to the parietal region may experience an increased difficulty in decision-making regarding targets located in the contralesional field.
Although it would typically require special circumstances for a non-impaired person to produce an illusory conjunction, it appears that some patients with damage to the parietal cortex may demonstrate a vulnerability to such visuospatial impairments.
Specifically, frontal lobe damage has been associated with a deficit in the control of over attention (the production of eye movements).
The right lateral frontal lobe region was also found to be associated with left-sided visual neglect in an investigation carried out by Husain & Kennard.
[29] A region of overlap was found in the location of lesions in four of five patients with left-sided visual neglect, specifically the dorsal aspect of the inferior frontal gyrus and the underlying white matter.
[31] Specifically, the pulvinar nucleus appears to be implicated in the subcortical control of spatial attention, and lesions in this area can cause neglect.
[10] Evidence[31] suggests that the pulvinar nucleus of the thalamus might be responsible for engaging in spatial attention at a previously cued location.
A study by Rafal and Posner[31] found that patients who had acute pulvinar lesions were slower to detect a target which appeared in the contralesional visuospatial field compared to the appearance of a target in the ipsilesional field during a spatial cuing task.
This suggests a deficit in the ability to use attention to improve performance in detection and processing of visual targets in the contralesional region.