scholarly journals Microsaccades and attention in a high-acuity visual alignment task

2019 ◽  
Author(s):  
Rakesh Nanjappa ◽  
Robert M. McPeek
Keyword(s):  
Spatial Attention ◽  
Cognitive Processes ◽  
Small Region ◽  
Covert Attention ◽  
Letter Detection ◽  
Fixed Target ◽  
Viewing Condition ◽  
Alignment Task ◽  
High Acuity ◽  
Subsequent Effect

ABSTRACTWhile aiming and shooting, we make tiny eye movements called microsaccades that shift gaze between task-relevant objects within a small region. However, in the brief period before pressing trigger, microsaccades are suppressed. This might be due to the lack of the requirement to shift gaze as the retinal images of the two objects start overlapping on fovea. Or we might be actively suppressing microsaccades to prevent any disturbances in visual perception caused by microsaccades around the time of their occurrence and their subsequent effect on shooting performance.In this study we looked at microsaccade rate while participants performed a simulated shooting task under two conditions: normal viewing in which they moved their eyes freely and eccentric condition in which they maintained gaze on a fixed target while performing shooting task at 5° eccentricity. As expected, microsaccade rate dropped at the end of the task in the normal viewing condition. However, we found the same for the eccentric condition in which microsaccade did not shift gaze between the task objects.Microsaccades are also produced in response to shifts in covert attention. To test whether disengagement of covert attention from eccentric shooting location caused the drop in microsaccade rate, we monitored participant’s spatial attention location by employing a RSVP task simultaneously at a location opposite to the shooting task. Target letter detection at RSVP location did not improve during the drop in microsaccade rate, suggesting that covert attention was maintained at the shooting task location.We conclude that in addition to their usual gaze-shifting function, microsaccades during fine acuity tasks might be modulated by cognitive processes other than spatial attention.

What a Simple Letter-Detection Task Can Tell Us About Cognitive Processes in Reading

2016 ◽  
Vol 25 (6) ◽  
pp. 417-424 ◽  
Author(s):  
Raymond M. Klein ◽  
Jean Saint-Aubin
Keyword(s):  
Cognitive Processes ◽  
Visual Presentation ◽  
Detection Task ◽  
Societal Implications ◽  
Large Set ◽  
Letter Detection ◽  
Attentional Disengagement ◽  
The Past ◽  
Lexical Activation ◽  
Current Article

Understanding reading is a central issue for psychology, with major societal implications. Over the past five decades, a simple letter-detection task has been used as a window on the psycholinguistic processes involved in reading. When readers are asked to read a text for comprehension while marking with a pencil all instances of a target letter, they miss some of the letters in a systematic way known as the missing-letter effect. In the current article, we review evidence from studies that have emphasized neuroimaging, eye movement, rapid serial visual presentation, and auditory passages. As we review, the missing-letter effect captures a wide variety of cognitive processes, including lexical activation, attention, and extraction of phrase structure. To account for the large set of findings generated by studies of the missing-letter effect, we advanced an attentional-disengagement model that is rooted in how attention is allocated to and disengaged from lexical items during reading, which we have recently shown applies equally to listening.

scholarly journals Sustained spatial attention accounts for the direction bias of human microsaccades

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cheng Xue ◽  
Antonino Calapai ◽  
Julius Krumbiegel ◽  
Stefan Treue
Keyword(s):  
Spatial Attention ◽  
Human Subjects ◽  
Covert Attention ◽  
Saccade Target ◽  
Peripheral Stimulus ◽  
Visual Spatial Attention ◽  
Specific Effects ◽  
Visual Spatial ◽  
Attention Tasks ◽  
Direction Effect

AbstractSmall ballistic eye movements, so called microsaccades, occur even while foveating an object. Previous studies using covert attention tasks have shown that shortly after a symbolic spatial cue, specifying a behaviorally relevant location, microsaccades tend to be directed toward the cued location. This suggests that microsaccades can serve as an index for the covert orientation of spatial attention. However, this hypothesis faces two major challenges: First, effects associated with visual spatial attention are hard to distinguish from those that associated with the contemplation of foveating a peripheral stimulus. Second, it is less clear whether endogenously sustained attention alone can bias microsaccade directions without a spatial cue on each trial. To address the first issue, we investigated the direction of microsaccades in human subjects while they attended to a behaviorally relevant location and prepared a response eye movement either toward or away from this location. We find that directions of microsaccades are biased toward the attended location rather than towards the saccade target. To tackle the second issue, we verbally indicated the location to attend before the start of each block of trials, to exclude potential visual cue-specific effects on microsaccades. Our results indicate that sustained spatial attention alone reliably produces the microsaccade direction effect. Overall, our findings demonstrate that sustained spatial attention alone, even in the absence of saccade planning or a spatial cue, is sufficient to explain the direction bias observed in microsaccades.

Sensory and cognitive processes of shifts of spatial attention induced by numbers: An ERP study

Cortex ◽  
2008 ◽  
Vol 44 (4) ◽  
pp. 406-413 ◽  
Author(s):  
E SALILLAS ◽  
R ELYAGOUBI ◽  
C SEMENZA
Keyword(s):  
Spatial Attention ◽  
Cognitive Processes

scholarly journals Trunk Orientation Induces Neglect-Like Lateral Biases in Covert Attention

2002 ◽  
Vol 13 (6) ◽  
pp. 553-556 ◽  
Author(s):  
Jefferson D. Grubb ◽  
Catherine L. Reed
Keyword(s):  
Spatial Attention ◽  
Response Times ◽  
Covert Attention ◽  
Trunk Rotation ◽  
Attention Task ◽  
Unilateral Neglect ◽  
New Locations ◽  
The Right ◽  
Trunk Orientation ◽  
Neurologically Intact

The purpose of this study was to resolve a paradox in the literature on the effects of body orientation on spatial attention. Neuropsychological studies have found that real or simulated trunk rotation relieves contralesional inattention in patients with unilateral neglect, suggesting that trunk orientation affects how attention is allocated to space. However, in two previous studies, trunk orientation did not affect spatial attention in other populations. In this study, we investigated the effects of trunk orientation on the performance of a covert attention task by neurologically intact adults. The covert attention task allowed the evaluation of the effects of trunk orientation on both the allocation of attention to space and the ability to shift that attention to new locations. As in previous research, trunk orientation did not affect participants' response times (RTs) to validly cued targets. However, rotating participants' trunks to the left increased their RTs to invalidly cued targets on the right and decreased their RTs to invalidly cued targets on the left. These results indicate that trunk orientation induces directional biases in the ability to shift attention. Thus, for intact participants, trunk rotation created lateral biases in the covert attention task similar to those seen in neglect patients.

scholarly journals Associations and Dissociations between Oculomotor Readiness and Covert Attention

Vision ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 17 ◽  
Author(s):  
Soazig Casteau ◽  
Daniel T. Smith
Keyword(s):  
Spatial Attention ◽  
Theoretical Models ◽  
Covert Attention ◽  
Exogenous Attention ◽  
Exogenous Orienting ◽  
Mental Processes ◽  
Endogenous Orienting ◽  
Covert Orienting ◽  
Profound Influence ◽  
Premotor Theory

The idea that covert mental processes such as spatial attention are fundamentally dependent on systems that control overt movements of the eyes has had a profound influence on theoretical models of spatial attention. However, theories such as Klein’s Oculomotor Readiness Hypothesis (OMRH) and Rizzolatti’s Premotor Theory have not gone unchallenged. We previously argued that although OMRH/Premotor theory is inadequate to explain pre-saccadic attention and endogenous covert orienting, it may still be tenable as a theory of exogenous covert orienting. In this article we briefly reiterate the key lines of argument for and against OMRH/Premotor theory, then evaluate the Oculomotor Readiness account of Exogenous Orienting (OREO) with respect to more recent empirical data. These studies broadly confirm the importance of oculomotor preparation for covert, exogenous attention. We explain this relationship in terms of reciprocal links between parietal ‘priority maps’ and the midbrain oculomotor centres that translate priority-related activation into potential saccade endpoints. We conclude that the OMRH/Premotor theory hypothesis is false for covert, endogenous orienting but remains tenable as an explanation for covert, exogenous orienting.

scholarly journals Decoding and Reconstructing the Focus of Spatial Attention from the Topography of Alpha-band Oscillations

2016 ◽  
Vol 28 (8) ◽  
pp. 1090-1097 ◽  
Author(s):  
Jason Samaha ◽  
Thomas C. Sprague ◽  
Bradley R. Postle
Keyword(s):  
Spatial Attention ◽  
Sustained Attention ◽  
Spatial Location ◽  
Covert Attention ◽  
Alpha Power ◽  
Alpha Band ◽  
Temporal Precision ◽  
Neural Populations ◽  
Stimulus Features ◽  
Spatial Locations

Many aspects of perception and cognition are supported by activity in neural populations that are tuned to different stimulus features (e.g., orientation, spatial location, color). Goal-directed behavior, such as sustained attention, requires a mechanism for the selective prioritization of contextually appropriate representations. A candidate mechanism of sustained spatial attention is neural activity in the alpha band (8–13 Hz), whose power in the human EEG covaries with the focus of covert attention. Here, we applied an inverted encoding model to assess whether spatially selective neural responses could be recovered from the topography of alpha-band oscillations during spatial attention. Participants were cued to covertly attend to one of six spatial locations arranged concentrically around fixation while EEG was recorded. A linear classifier applied to EEG data during sustained attention demonstrated successful classification of the attended location from the topography of alpha power, although not from other frequency bands. We next sought to reconstruct the focus of spatial attention over time by applying inverted encoding models to the topography of alpha power and phase. Alpha power, but not phase, allowed for robust reconstructions of the specific attended location beginning around 450 msec postcue, an onset earlier than previous reports. These results demonstrate that posterior alpha-band oscillations can be used to track activity in feature-selective neural populations with high temporal precision during the deployment of covert spatial attention.

Supramodal Effects of Covert Spatial Orienting Triggered by Visual or Tactile Events

2002 ◽  
Vol 14 (3) ◽  
pp. 389-401 ◽  
Author(s):  
E. Macaluso ◽  
C. D. Frith ◽  
J. Driver
Keyword(s):  
Frontal Cortex ◽  
Spatial Attention ◽  
Covert Attention ◽  
Spatial Coding ◽  
Brain Areas ◽  
Target Modality ◽  
Spatial Orienting ◽  
Inferior Frontal Cortex ◽  
Trial Basis ◽  
Subsequent Target

Event-related functional magnetic resonance imaging was used to identify brain areas involved in spatial attention and determine whether these operate unimodally or supramodally for vision and touch. On a trial-by-trial basis, a symbolic auditory cue indicated the most likely side for the subsequent target, thus directing covert attention to one side. A subsequent target appeared in vision or touch on the cued or uncued side. Invalidly cued trials (as compared with valid trials) activated the temporo-parietal junction and regions of inferior frontal cortex, regardless of target modality. These brain areas have been associated with multimodal spatial coding in physiological studies of the monkey brain and were linked to a change in the location that must be attended to in the present study. The intraparietal sulcus and superior frontal cortex were also activated in our task, again, regardless of target modality, but did not show any specificity for invalidly cued trials. These results identify a supramodal network for spatial attention and reveal differential activity for inferior circuits involving the temporo-parietal junction and inferior frontal cortex (specific to invalid trials) versus more superior intraparietal-frontal circuits (common to valid and invalid trials).

scholarly journals Microsaccades and attention in a high-acuity visual alignment task

2021 ◽  
Vol 21 (2) ◽  
pp. 6
Author(s):  
Rakesh Nanjappa ◽  
Robert M. McPeek
Keyword(s):  
Alignment Task ◽  
High Acuity

Neuronal Mechanisms of Attentional Control

2014 ◽  
Author(s):  
Kelsey L. Clark ◽  
Behrad Noudoost ◽  
Robert J. Schafer ◽  
Tirin Moore
Keyword(s):  
Spatial Attention ◽  
Covert Attention ◽  
Extrastriate Cortex ◽  
Frontal Eye Field ◽  
Neural Signals ◽  
Electrical Microstimulation ◽  
Visual Spatial ◽  
Neuronal Mechanisms ◽  
Eye Field ◽  
Visual Cortical

Covert spatial attention prioritizes the processing of stimuli at a given peripheral location, away from the direction of gaze, and selectively enhances visual discrimination, speed of processing, contrast sensitivity, and spatial resolution at the attended location. While correlates of this type of attention, which are believed to underlie perceptual benefits, have been found in a variety of visual cortical areas, more recent observations suggest that these effects may originate from frontal and parietal areas. Evidence for a causal role in attention is especially robust for the Frontal Eye Field, an oculomotor area within the prefrontal cortex. FEF firing rates have been shown to reflect the location of voluntarily deployed covert attention in a variety of tasks, and these changes in firing rate precede those observed in extrastriate cortex. In addition, manipulation of FEF activity—whether via electrical microstimulation, pharmacologically, or operant conditioning—can produce attention-like effects on behaviour and can modulate neural signals within posterior visual areas. We review this evidence and discuss the role of the FEF in visual spatial attention.

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