Spatial Attention Deficits in Patients with Acquired or Developmental Cerebellar Abnormality

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.

Electrophysiological and behavioral responses were recorded in healthy young (19-23 years) and older (56-66 years) subjects during the execution of a visuospatial attention task. The objective was to test whether covert orienting of visuospatial attention (COVAT) is sensitive to the early stages of aging. All subjects responded faster to targets following valid than invalid cues. The amplitude of the P1 component of visual event-related potentials (ERP) was larger to targets following central valid cues at all SOAs. Subtle age-related changes were observed in P1 amplitude under peripheral cueing. Furthermore, older subjects presented longer reaction times (RTs) and lower P1 amplitudes regardless of the attention condition.

Although migraine is classified as a headache disorder, a key part of migraine pathophysiology is a heightened excitability of visual cortices in between headache events. The goal of our study was to examine the behavioral impact of this visuocortical hyperexcitability, in terms of its effect on reflexive visual attentional orienting. In Experiment 1, using a non-predictive spatial cuing task that relied on sensory-evoked responses in the visual cortex for triggering attentional orienting, we found that migraineurs had greater attentional enhancement of manual target responses, relative to non-migraine controls. In two control experiments we confirmed that this heightened attention effect in migraineurs is not due to exaggerated reflexive orienting responses in general, but rather, it appears to be specifically associated with sensory-evoked attentional triggers. Taken together, this confirms that the functional consequences of hyperexcitable visual cortex in migraineurs are not just purely sensory in nature, but directly impact at least some forms of reflexive attention. This provides evidence of at least one cognitive implication of hyperexcitable visual cortical responses in migraineurs, namely heightened reflexive visual-spatial orienting specific to sudden-onset peripheral events.

Masked stimuli modulate endogenous shifts of spatial attention

It is still unclear whether impairments in visuospatial processing in children with developmental coordination disorder (DCD) are a consequence of their motor deficits or are independent of them. In two experiments, 20 children with DCD and 20 matched controls were tested on the covert orienting of a visuospatial attention task (COVAT). Experiment 1 used a COVAT with peripheral cues and an 80% probability that targets would appear at the cued location. While the results suggested a deficit in the disengage operation of orienting covert attention for the DCD group, they were difficult to reconcile with models of covert orienting and the results of past research. Experiment 2 tested subjects on two new versions of the COVAT: the first used peripheral cues and no probability information (exogenous mode), and the second used central cues and an 80% probability that targets would appear at the cued location (endogenous mode). The DCD group displayed attentional orienting deficits only for the endogenous mode. These results suggest that impairments in the endogenous control of visuospatial attention are independent of motor deficits in DCD.

The purpose of this study was to determine if the ability to set attention is different between athletes and nonathletes. University volleyball players were compared with nonathletes on a spatial cuing task similar to that of C. L. Folk, R. W. Remington, and J. C. Johnston (1992). As expected, both groups showed evidence of entering into a specific attentional set because attentional cuing effects were found only when cues and targets shared a task-relevant feature (onset or color). In addition, the cuing effects when the cues matched the targets were greater for the athletes than for the nonathletes. The results are discussed in terms of the orienting of attention and athletic performance.

We investigated whether words relevant to a person’s current goal and words related to that goal influence the orienting of attention even when an intention to attend to the goal-relevant and goal-related stimuli is not present. Participants performed a modified spatial cueing paradigm combined with a second task that induced a goal. The results showed that the induced goal led to the orienting of attention to goal-relevant words in the spatial cueing task. This effect was not found for goal-related words. The results provide evidence for accounts of automatic goal pursuit, which state that goals automatically guide attention to goal-relevant events.

Studies have explored how human spatial attention appears allocated in three-dimensional (3D) space. It has been demonstrated that target distance from the viewer can modulate performance in target detection and localization tasks: reaction times are shorter when targets appear nearer to the observer compared to farther distances (i.e., near advantage). Times have reached to quantitatively analyze this literature. In the current meta-analysis, 29 studies (n = 1260 participants) examined target detection and localization across 3-D space. Moderator analyses included: detection vs localization tasks, spatial cueing vs uncued tasks, control of retinal size across depth, central vs peripheral targets, real-space vs stereoscopic vs monocular depth environments, and inclusion of in-trial motion. The analyses revealed a near advantage for spatial attention that was affected by the moderating variables of controlling for retinal size across depth, the use of spatial cueing tasks, and the inclusion of in-trial motion. Overall, these results provide an up-to-date quantification of the effect of depth and provide insight into methodological differences in evaluating spatial attention.

The effects of aging on alerting, orienting, and executive function were examined with the use of the Attention Network Task, which combines the Posner spatial cuing task and the Eriksen flanker task into a single procedure. We found that older adults showed significantly less alerting than young adults in response to a warning cue, although there were no age differences in orienting or executive function once processing speed was taken into account. We suggest that age differences in alerting may depend in part upon the presentation duration or persistence of the warning cue.

Multivariate pattern analysis of the neural correlates of smoking cue attentional bias

C-03 遮蔽された物体上での視覚的注意の広がり : 空間的手がかり課題による検討

In addition to its role in shifting the line of sight, the oculomotor system is also involved in the covert orienting of visuospatial attention. Causal evidence supporting this premotor theory of attention, or oculomotor readiness hypothesis, comes from the effect of subsaccadic threshold stimulation of the oculomotor system on behavior and neural activity in the absence of evoked saccades, which parallels the effects of covert attention. Here, by recording neck-muscle activity from monkeys and systematically titrating the level of stimulation current delivered to the frontal eye fields (FEF), we show that such subsaccadic stimulation is not divorced from immediate motor output but instead evokes neck-muscle responses at latencies that approach the minimal conduction time to the motor periphery. On average, neck-muscle thresholds were approximately 25% lower than saccade thresholds, and this difference is larger for FEF sites associated with progressively larger saccades. Importantly, we commonly observed lower neck-muscle thresholds even at sites evoking saccades <or=5 degrees in magnitude, although such small saccades are not associated with head motion. Neck-muscle thresholds compare well with the current levels used in previous studies to influence behavior or neural activity through activation of FEF neurons feeding back to extrastriate cortex. Our results complement this previous work by suggesting that the neurobiologic substrate that covertly orients visuospatial attention shares this command with head premotor circuits in the brainstem, culminating with recruitment in the motor periphery.

Pupil responses and optokinetic nystagmus (OKN) are known to vary with the brightness and direction of motion of attended stimuli, as well as gaze position. However, whether these processes are controlled by a common mechanism remains unclear. In this study, we investigated how OKN latency relates to pupil response latency under two conditions: gaze shifts (eye movement) and attention shifts (covert attention without eye movement). As a result, while OKN showed consistent temporal changes across both gaze and attention conditions, pupillary responses exhibited distinct patterns. Moreover, the results revealed no significant correlation between pupil latency and OKN latency in either condition. These findings suggest that, although OKN and pupillary responses are influenced by similar attentional processes, their underlying mechanisms may differ.

The ups and downs (and lefts and rights) of synaesthetic number forms: Validation from spatial cueing and SNARC-type tasks

More recent findings suggest a possible role of the cerebellum in nonmotor functions. Disability of individuals with cerebellar damage in rapidly shifting attention is one frequently used example to support cerebellar involvement in mental skills. The original proposal was based on findings in five children with chronic surgical lesions of the cerebellum and a young adult with a degenerative disorder. The aim of the present study was to repeat Akshoomoff and Courchesne's initial findings in a larger group of children with focal cerebellar lesions. Ten children with cerebellar lesions and 10 age- and sex-matched controls were tested. Neocerebellar areas were affected in all children with cerebellar damage except one based on detailed analysis of MRI scans. Subjects had to perform a focus and a shift attention task. Two visual and two auditory stimuli were presented in a pseudorandom order. An ellipse and a high-pitched tone were presented less frequently than a circle and a low-pitched tone. Rare stimuli were presented at five different time intervals. In the focus tasks, subjects had to react to the same rare stimulus of one of the two modalities. In the shift task, subjects had to switch between the two rare stimuli. Motor deficits based on reaction times were small in cerebellar children compared with controls. The ability of target detection did not significantly differ in the children with cerebellar lesions compared with the control children in both the focus and the shift attention task. In particular, children with cerebellar damage showed no significant impairment in rapid (<2 s) shifts of attention. The present findings indicate that the cerebellum may be less critical in attention related processes than suggested previously.