Control Of Visual Spatial Attention Research Articles

Dissociating the Contributions of Frontal Eye Field Activity to Spatial Working Memory and Motor Preparation.

Neurons within dorsolateral prefrontal cortex (PFC) of primates are characterized by robust persistent spiking activity exhibited during the delay period of working memory tasks. This includes the frontal eye field (FEF) where nearly half of the neurons are active when spatial locations are held in working memory. Past evidence has established the FEF's contribution to the planning and triggering of saccadic eye movements as well as to the control of visual spatial attention. However, it remains unclear whether persistent delay activity reflects a similar dual role in movement planning and visuospatial working memory. We trained male monkeys to alternate between different forms of a spatial working memory task which could dissociate remembered stimulus locations from planned eye movements. We tested the effects of inactivation of FEF sites on behavioral performance in the different tasks. Consistent with previous studies, FEF inactivation impaired the execution of memory-guided saccades (MGSs), and impaired performance when remembered locations matched the planned eye movement. In contrast, memory performance was largely unaffected when the remembered location was dissociated from the correct eye movement response. Overall, the inactivation effects demonstrated clear deficits in eye movements, regardless of task type, but little or no evidence of a deficit in spatial working memory. Thus, our results indicate that persistent delay activity in the FEF contributes primarily to the preparation of eye movements and not to spatial working memory.SIGNIFICANCE STATEMENT Many frontal eye field (FEF) neurons exhibit spatially tuned persistent spiking activity during the delay period of working memory tasks. However, the role of the FEF in spatial working memory remains unresolved. We tested the effects of inactivation of FEF sites on behavioral performance in different forms of a spatial working memory task, one of which dissociated the remembered stimulus locations from planned eye movements. We found that FEF inactivation produced clear deficits in eye movements, regardless of task type, but no deficit in spatial working memory when dissociated from those movements.

Information Connectivity (IC) Reveals Signaling Pathways in Visual Spatial Attention Control and Selection

Information Connectivity (IC) Reveals Signaling Pathways in Visual Spatial Attention Control and Selection

Decoding Visual Feature Versus Visual Spatial Attention Control with Deep Neural Networks

Decoding Visual Feature Versus Visual Spatial Attention Control with Deep Neural Networks

Top-down control of the left visual field bias in cued visual spatial attention.

A left visual field (LVF) bias in perceptual judgments, response speed, and discrimination accuracy has been reported in humans. Cognitive factors, such as visual spatial attention, are known to modulate or even eliminate this bias. We investigated this problem by recording pupillometry together with functional magnetic resonance imaging (fMRI) in a cued visual spatial attention task. We observed that (i) the pupil was significantly more dilated following attend-right than attend-left cues, (ii) the task performance (e.g. reaction time [RT]) did not differ between attend-left and attend-right trials, and (iii) the difference in cue-related pupil dilation between attend-left and attend-right trials was inversely related to the corresponding difference in RT. Neuroscientically, correlating the difference in cue-related pupil dilation with the corresponding cue-related fMRI difference yielded activations primarily in the right hemisphere, including the right intraparietal sulcus and the right ventrolateral prefrontal cortex. These results suggest that (i) there is an asymmetry in visual spatial attention control, with the rightward attention control being more effortful than the leftward attention control, (ii) this asymmetry underlies the reduction or the elimination of the LVF bias, and (iii) the components of the attentional control networks in the right hemisphere are likely part of the neural substrate of the observed asymmetry in attentional control.

Differential Expression of Dopamine D5 Receptors across Neuronal Subtypes in Macaque Frontal Eye Field.

Dopamine signaling in the prefrontal cortex (PFC) is important for cognitive functions, yet very little is known about the expression of the D5 class of dopamine receptors (D5Rs) in this region. To address this, we co-stained for D5Rs, pyramidal neurons (neurogranin+), putative long-range projection pyramidal neurons (SMI-32+), and several classes of inhibitory interneuron (parvalbumin+, calbindin+, calretinin+, somatostatin+) within the frontal eye field (FEF): an area within the PFC involved in the control of visual spatial attention. We then quantified the co-expression of D5Rs with markers of different cell types across different layers of the FEF. We show that: (1) D5Rs are more prevalent on pyramidal neurons than on inhibitory interneurons. (2) D5Rs are disproportionately expressed on putative long-range projecting pyramidal neurons. The disproportionately high expression of D5Rs on long-range projecting pyramidals, compared to interneurons, was particularly pronounced in layers II–III. Together these results indicate that the engagement of D5R-dependent mechanisms in the FEF varies depending on cell type and cortical layer, and suggests that non-locally projecting neurons contribute disproportionately to functions involving the D5R subtype.

The Gaze-Cueing Effect in the United States and Japan: Influence of Cultural Differences in Cognitive Strategies on Control of Attention.

The direction of gaze automatically and exogenously guides visual spatial attention, a phenomenon termed as the gaze-cueing effect. Although this effect arises when the duration of stimulus onset asynchrony (SOA) between a non-predictive gaze cue and the target is relatively long, no empirical research has examined the factors underlying this extended cueing effect. Two experiments compared the gaze-cueing effect at longer SOAs (700 ms) in Japanese and American participants. Cross-cultural studies on cognition suggest that Westerners tend to use a context-independent analytical strategy to process visual environments, whereas Asians use a context-dependent holistic approach. We hypothesized that Japanese participants would not demonstrate the gaze-cueing effect at longer SOAs because they are more sensitive to contextual information, such as the knowledge that the direction of a gaze is not predictive. Furthermore, we hypothesized that American participants would demonstrate the gaze-cueing effect at the long SOAs because they tend to follow gaze direction whether it is predictive or not. In Experiment 1, American participants demonstrated the gaze-cueing effect at the long SOA, indicating that their attention was driven by the central non-predictive gaze direction regardless of the SOAs. In Experiment 2, Japanese participants demonstrated no gaze-cueing effect at the long SOA, suggesting that the Japanese participants exercised voluntary control of their attention, which inhibited the gaze-cueing effect with the long SOA. Our findings suggest that the control of visual spatial attention elicited by social stimuli systematically differs between American and Japanese individuals.

Supplemental Material for Functional Consequences of Compositional Spatial Representations Elicited During Conceptual Control of Visual Spatial Attention

Supplemental Material for Functional Consequences of Compositional Spatial Representations Elicited During Conceptual Control of Visual Spatial Attention

Functional consequences of compositional spatial representations elicited during conceptual control of visual spatial attention.

Reference frames are ubiquitous in spatial cognition, and they have been especially important in the visual attention literature. Researchers typically invoke these constructs to explain how the same physical location can be defined in different ways depending on changes in the reference point. However, when researchers invoke reference frames for this purpose, they also tend to invoke a construct-the Cartesian coordinate system-that has a specific compositional structure. This conclusion may not be warranted though because reference frames can be used to define a location without being compositional in nature. The present study used an attention cuing paradigm to examine the potential consequences of encoding spatial locations within compositional (coordinate) spatial representations. Experiment 1 used 75% valid, compositional cues that conveyed separate information about the likely direction and distance of the target. The main results were consistent with the notion that a Cartesian coordinate reference system was used to interpret these cues which in turn elicited a compositional gradient that reflected the combined activation arising from the separate spatial dimensions. Experiment 2 ruled out an alternative account and Experiment's 3 and 4 examined the dynamic nature of these gradients over time. These findings were interpreted within a theory of conceptual control that distinguished between conceptual and perceptual representations of space. Conceptual representations are compositional and can be used to guide attention from one object to another. But conceptual representations depend on noncompositional, perceptual representations to bind the activations arising from their separate spatial dimensions, much like nonspatial feature dimensions do. (PsycINFO Database Record

Effects of walking on bilateral differences in spatial attention control: a cross-over design

BackgroundWalking requires a high attentional cost for balance control and interferes with the control of attention. However, it is unclear whether the performance of visual spatial attention control, which is one of the functions of attention control, is also decreased during walking. In addition, although previous studies have shown right-hemispheric dominance and lower ability of left side visual spatial attention control during sitting, it remains unknown whether walking accentuates bilateral differences in visual spatial attention control. We tested the hypothesis that walking interferes with visual spatial attention control on both sides and accentuates its bilateral differences.MethodsTwenty healthy right-handed subjects (24.3 ± 2.0 years) participated in this study. Subjects performed a random stimulus–response compatibility (SRC) task during both sitting and walking situations. To evaluate the effects of walking, reaction time was measured on both sides for the two situations. In comparison to the both situations (sitting and walking), the amount of change of the SRC effect on both sides was used. In the comparing the bilateral difference (left and right), the difference of the SRC effect was evaluated in each situation. The paired t-test was applied to both comparisons for statistical analysis.ResultsThe SRC effect on both sides during walking was significantly larger than during sitting (P < 0.05). In addition, walking significantly accentuated the bilateral differences in visual spatial attention control (P < 0.05).ConclusionsThese results suggest that walking affects the performance of visual spatial attention control on both sides and accentuates its bilateral differences. These results have implications for development of practice methods of gait disorder with higher brain dysfunction.

Effects of Sustained Spatial Attention in the Human Lateral Geniculate Nucleus and Superior Colliculus

The role of subcortical visual structures such as the lateral geniculate nucleus (LGN) and the superior colliculus (SC) in the control of visual spatial attention remains poorly understood. Here, we used high-resolution functional magnetic resonance imaging to measure responses in the human LGN and SC during sustained spatial attention. Subjects covertly and continuously tracked one of two segments that rotated through the visual field, composed of either moving dots or transient colored shapes. Activity in both nuclei was generally enhanced by attention, independent of the stimulus type, with the voxels responding more sensitively to stimulus contrast (those dominated by magnocellular input) exhibiting greater attentional enhancement. The LGN contained clusters of voxels exhibiting attentional enhancement or weak suppression, whereas the SC exhibited predominantly attentional enhancement, which was significantly stronger than in the LGN. The spatial distribution of the attentional effects was unrelated to the retinotopic organization in either structure. The results demonstrate that each of the major subcortical visual pathways participates in attentional selection, and their differential magnitudes of modulation suggest distinct roles.

The neural circuitry underlying the executive control of auditory spatial attention

Although a fronto-parietal network has consistently been implicated in the control of visual spatial attention, the network that guides spatial attention in the auditory domain is not yet clearly understood. To investigate this issue, we measured brain activity using functional magnetic resonance imaging while participants performed a cued auditory spatial attention task. We found that cued orienting of auditory spatial attention activated a medial–superior distributed fronto-parietal network. In addition, we found cue-triggered increases of activity in the auditory sensory cortex prior to the occurrence of an auditory target, suggesting that auditory attentional control operates in part by biasing processing in sensory cortex in favor of expected target stimuli. Finally, an exploratory cross-study comparison further indicated several common frontal and parietal regions as being involved in the control of both visual and auditory spatial attention. Thus, the present findings not only reveal the network of brain areas underlying endogenous spatial orienting in the auditory modality, but also suggest that the control of spatial attention in different sensory modalities is enabled in part by some common, supramodal neural mechanisms.

Top-down gain control of the auditory space map by gaze control circuitry in the barn owl

High-level circuits in the brain that control the direction of gaze are intimately linked with the control of visual spatial attention. Immediately before an animal directs its gaze towards a stimulus, both psychophysical sensitivity to that visual stimulus and the responsiveness of high-order neurons in the cerebral cortex that represent the stimulus increase dramatically. Equivalent effects on behavioural sensitivity and neuronal responsiveness to visual stimuli result from focal electrical microstimulation of gaze control centres in monkeys. Whether the gaze control system modulates neuronal responsiveness in sensory modalities other than vision is unknown. Here we show that electrical microstimulation applied to gaze control circuitry in the forebrain of barn owls regulates the gain of midbrain auditory responses in an attention-like manner. When the forebrain circuit was activated, midbrain responses to auditory stimuli at the location encoded by the forebrain site were enhanced and spatial selectivity was sharpened. The same stimulation suppressed responses to auditory stimuli represented at other locations in the midbrain map. Such space-specific, top-down regulation of auditory responses by gaze control circuitry in the barn owl suggests that the central nervous system uses a common strategy for dynamically regulating sensory gain that applies across modalities, brain areas and classes of vertebrate species. This approach provides a path for discovering mechanisms that underlie top-down gain control in the central nervous system.

On the control of visual spatial attention: evidence from human electrophysiology

We used electrophysiological methods to track the deployment of visual spatial attention while observers were engaged in concurrent central attentional processing, using a variant of the attentional blink paradigm. Two visual targets (T1, T2) were presented at a stimulus onset asynchrony of either 200 ms or 800 ms. T1 was a white digit among white letters presented on a dark background using rapid serial visual presentation at fixation. T2 was another digit that was presented to the left or right of fixation simultaneously with a distractor digit in the opposite visual field, each followed by a pattern mask. In each T2 display, one digit was red and one was green. Half of the subjects reported the red digit and ignored the green one, whereas the other half reported the green digit and ignored the red one. T1 and T2 were reported in one block of trials, and only T2 in another block (order counterbalanced across subjects). Accuracy of report of T2 was lower at short SOA than at long SOA when both T1 and T2 were reported, but was similar across SOA when only T2 was reported. The electrophysiological results focused on the N2pc component, which was used as an index of the locus of spatial attention. N2pc was reduced in amplitude when subjects reported T1, and particularly so at the short SOA. The results suggest that attention to T1 interfered with the deployment of visual spatial attention to T2.

Visual Spatial Attention Control in an Independent Brain-Computer Interface

This paper presents a novel brain computer interface (BCI) design employing visual evoked potential (VEP) modulations in a paradigm involving no dependency on peripheral muscles or nerves. The system utilizes electrophysiological correlates of visual spatial attention mechanisms, the self-regulation of which is naturally developed through continuous application in everyday life. An interface involving real-time biofeedback is described, demonstrating reduced training time in comparison to existing BCIs based on self-regulation paradigms. Subjects were cued to covertly attend to a sequence of letters superimposed on a flicker stimulus in one visual field while ignoring a similar stimulus of a different flicker frequency in the opposite visual field. Classification of left/right spatial attention is achieved by extracting steady-state visual evoked potentials (SSVEPs) elicited by the stimuli. Six out of eleven physically and neurologically healthy subjects demonstrate reliable control in binary decision-making, achieving at least 75% correct selections in at least one of only five sessions, each of approximately 12-min duration. The highest-performing subject achieved over 90% correct selections in each of four sessions. This independent BCI may provide a new method of real-time interaction for those with little or no peripheral control, with the added advantage of requiring only brief training.

The attentive homunculus: Now you see it, now you don't

The nature of the neural system that directs our attention toward selective items in the extrapersonal world is a longstanding and interesting puzzle. The ability to image the human brain at work non-invasively using positron-emission tomography or functional magnetic resonance has provided the means to investigate this issue. In this article, I review the contributions of brain imaging toward the characterization of attentional control in the human brain. The majority of experiments to date have investigated visual spatial orienting. A consistent pattern of brain areas has been revealed, comprising most notably the posterior parietal cortex around the intraparietal sulcus and frontal regions including the frontal eye fields. The brain areas implicated in the control of visual spatial attention were noted to resemble those involved in the control of eye movements, and direct experimental comparisons supported a tight link between the two systems. The findings suggested a sensible view of the attentional ‘homunculus’ as a distributed neural system related to the control of eye movements. Eye movements form perhaps the most basic orienting response, and can be shifted rapidly and efficiently based on multiple frames of reference. Some attention experiments using objects and features instead of spatial locations as the target of selection also obtained similar patterns of parietal–frontal activations, rendering further support to this view of the attentional control system. Some recent experiments, however, have cautioned against a premature conclusion regarding the ubiquity of the attentional control system revealed by studies of visual spatial attention. Different parietal and frontal regions become engaged when attention is shifted along non-spatial dimensions, such as when attention is directed toward a particular motor act or toward a specific point in time. In these cases, the neural system resembles those involved in the control of limb movements. The attentional homunculus thus begins to dissolve. The alternative view suggested is that attentional control may be a property of specialized parietal–frontal systems that transform perception into action. Future studies will be needed to validate this view of attention, or to provide a more mature understanding of its true nature.

Orienting of visual attention in dyslexia: evidence for asymmetric hemispheric control of attention

The control of attentional orienting was studied in children with specific reading disorder (SRD) or dyslexia, and it was compared with that of normal readers. We used the covert orienting paradigm to measure subjects' reaction times for target detection both in valid and invalid cue conditions, either in the left or in the right visual fields. In experiment 1, we investigated exogenous orienting. The cue consisted of a peripheral abrupt onset and the cue-target delay was 350 ms. As compared with normal readers, in dyslexics the cue effect was absent in the right visual field, whereas in the left visual field a greater cue effect was observed. No visual field asymmetry was found in normal readers. In experiment 2, we investigated endogenous orienting. The cue was shown centrally and the cue-target delay was 750 ms. In dyslexics and normal readers, orienting of attention was present in both visual fields. However, in the invalid condition, dyslexic children showed significantly slower reaction times in the left visual field than in the right visual field. These results were interpreted as being due to an asymmetric control of visual spatial attention, possibly related with a posterior attention mechanism deficit in the right parietal cortex and/or an interhemispheric dysfunction and/or an impairment of cerebellar functions.

Asymmetrical hemispheric control of visual-spatial attention in adults with attention deficit hyperactivity disorder.

Asymmetrical hemispheric control of visual-spatial attention in adults with attention deficit hyperactivity disorder.

Linguistic and Conceptual Control of Visual Spatial Attention

A theory of voluntary, top-down control of visual spatial attention is presented that explains how linguistic cues like "above," "below," "left," and "right" are used to direct attention from one object to another. The theory distinguishes between perceptual and conceptual representations of space and views attention as a set of mechanisms that establish correspondences between the representations. Spatial reference frames play an important part in this analysis. The theory interprets reference frames as mechanisms of attention, similar to spatial indices but with more computational power. The theory was tested in 11 experiments that assessed the importance of linguistic distinctions between classes of spatial relations ( basic, deictic, and intrinsic) and examined the flexibility with which subjects manipulated spatial reference frames.