scholarly journals Brain regions modulated during covert visual attention in the macaque

2018 ◽  
Author(s):  
Amarender R. Bogadhi ◽  
Anil Bollimunta ◽  
David A. Leopold ◽  
Richard J. Krauzlis
Keyword(s):  
Visual Attention ◽  
Caudate Nucleus ◽  
Visual Motion ◽  
Brain Structures ◽  
Brain Regions ◽  
Covert Attention ◽  
Subcortical Structures ◽  
Covert Visual Attention ◽  
Sensory Neural ◽  
Orientation Stimulus

AbstractNeurophysiology studies of covert visual attention in monkeys have emphasized the modulation of sensory neural responses in the visual cortex. At the same time, electrophysiological correlates of attention have been reported in other cortical and subcortical structures, and recent fMRI studies have identified regions across the brain modulated by attention. Here we used fMRI in two monkeys performing covert attention tasks to reproduce and extend these findings in order to help establish a more complete list of brain structures involved in the control of attention. As expected from previous studies, we found attention-related modulation in frontal, parietal and visual cortical areas as well as the superior colliculus and pulvinar. We also found significant attention-related modulation in cortical regions not traditionally linked to attention – mid-STS areas (anterior FST and parts of IPa, PGa, TPO), as well as the caudate nucleus. A control experiment using a second-order orientation stimulus showed that the observed modulation in a subset of these mid-STS areas did not depend on visual motion. These results identify the mid-STS areas (anterior FST and parts of IPa, PGa, TPO) and caudate nucleus as potentially important brain regions in the control of covert visual attention in monkeys.

scholarly journals Neuronal modulation in the mouse superior colliculus during covert visual selective attention

2021 ◽  
Author(s):  
Lupeng Wang ◽  
James P. Herman ◽  
Richard J. Krauzlis
Keyword(s):  
Visual Attention ◽  
Selective Attention ◽  
Superior Colliculus ◽  
Firing Rate ◽  
Spatial Location ◽  
Relevant Information ◽  
Brain Regions ◽  
Uncued Location ◽  
Visual Selective Attention ◽  
Covert Visual Attention

AbstractCovert visual attention is accomplished by a cascade of mechanisms distributed across multiple brain regions. Recent studies in primates suggest a parcellation in which visual cortex is associated with enhanced representations of relevant stimuli, whereas subcortical circuits are associated with selection of visual targets and suppression of distractors. Here we identified how neuronal activity in the superior colliculus (SC) of head-fixed mice is modulated during covert visual attention. We found that spatial cues modulated both firing rate and spike-count correlations, and that the cue-related modulation in firing rate was due to enhancement of activity at the cued spatial location rather than suppression at the uncued location. This modulation improved the neuronal discriminability of visual-change-evoked activity between contralateral and ipsilateral SC neurons. Together, our findings indicate that neurons in the mouse SC contribute to covert visual selective attention by biasing processing in favor of locations expected to contain relevant information.

scholarly journals Covert Visual Attention Modulates Face-Specific Activity in the Human Fusiform Gyrus: fMRI Study

1998 ◽  
Vol 79 (3) ◽  
pp. 1574-1578 ◽  
Author(s):  
Ewa Wojciulik ◽  
Nancy Kanwisher ◽  
Jon Driver
Keyword(s):  
Visual Attention ◽  
Specific Activity ◽  
Region Of Interest ◽  
Fusiform Gyrus ◽  
Covert Attention ◽  
Matching Task ◽  
Voluntary Attention ◽  
Retinal Stimulation ◽  
Covert Visual Attention ◽  
Fmri Study

Wojciulik, Ewa, Nancy Kanwisher, and Jon Driver. Covert visual attention modulates face-specific activity in the human fusiform gyrus: an fMRI study. J. Neurophysiol. 79: 1574–1578, 1998. Several lines of evidence demonstrate that faces undergo specialized processing within the primate visual system. It has been claimed that dedicated modules for such biologically significant stimuli operate in a mandatory fashion whenever their triggering input is presented. However, the possible role of covert attention to the activating stimulus has never been examined for such cases. We used functional magnetic resonance imaging to test whether face-specific activity in the human fusiform face area (FFA) is modulated by covert attention. The FFA was first identified individually in each subject as the ventral occipitotemporal region that responded more strongly to visually presented faces than to other visual objects under passive central viewing. This then served as the region of interest within which attentional modulation was tested independently, using active tasks and a very different stimulus set. Subjects viewed brief displays each comprising two peripheral faces and two peripheral houses (all presented simultaneously). They performed a matching task on either the two faces or the two houses, while maintaining central fixation to equate retinal stimulation across tasks. Signal intensity was reliably stronger during face-matching than house matching in both right- and left-hemisphere predefined FFAs. These results show that face-specific fusiform activity is reduced when stimuli appear outside (vs. inside) the focus of attention. Despite the modular nature of the FFA (i.e., its functional specificity and anatomic localization), face processing in this region nonetheless depends on voluntary attention.

Neural Mechanisms of Visual Attention: Object-Based Selection of a Region in Space

2000 ◽  
Vol 12 (supplement 2) ◽  
pp. 106-117 ◽  
Author(s):  
Catherine M. Arrington ◽  
Thomas H. Carr ◽  
Andrew R. Mayer ◽  
Stephen M. Rao
Keyword(s):  
Visual Attention ◽  
Spatial Attention ◽  
Brain Activity ◽  
Temporal Cortex ◽  
Brain Structures ◽  
Brain Regions ◽  
Brain Areas ◽  
Unbounded Region ◽  
Object Based ◽  
Selection Of

Objects play an important role in guiding spatial attention through a cluttered visual environment. We used event-related functional magnetic resonance imaging (ER-fMRI) to measure brain activity during cued discrimination tasks requiring subjects to orient attention either to a region bounded by an object (object-based spatial attention) or to an unbounded region of space (location-based spatial attention) in anticipation of an upcoming target. Comparison between the two tasks revealed greater activation when attention selected a region bounded by an object. This activation was strongly lateralized to the left hemisphere and formed a widely distributed network including (a) attentional structures in parietal and temporal cortex and thalamus, (b) ventral-stream object processing structures in occipital, inferior-temporal, and parahippocampal cortex, and (c) control structures in medial-and dorsolateral-prefrontal cortex. These results suggest that object-based spatial selection is achieved by imposing additional constraints over and above those processes already operating to achieve selection of an unbounded region. In addition, ER-fMRI methodology allowed a comparison of validly versus invalidly cued trials, thereby delineating brain structures involved in the reorientation of attention after its initial deployment proved incorrect. All areas of activation that differentiated between these two trial types resulted from greater activity during the invalid trials. This outcome suggests that all brain areas involved in attentional orienting and task performance in response to valid cues are also involved on invalid trials. During invalid trials, additional brain regions are recruited when a perceiver recovers from invalid cueing and reorients attention to a target appearing at an uncued location. Activated brain areas specific to attentional reorientation were strongly right-lateralized and included posterior temporal and inferior parietal regions previously implicated in visual attention processes, as well as prefrontal regions that likely subserve control processes, particularly related to inhibition of inappropriate responding.

scholarly journals Semantic Influences on Overt and Covert Visual Attention

2021 ◽  
Author(s):  
◽  
Matthew David Weaver
Keyword(s):  
Visual Attention ◽  
Visual Information ◽  
Semantic Information ◽  
Past Research ◽  
Covert Attention ◽  
Attentional Orienting ◽  
Covert Visual Attention ◽  
Visual Orienting ◽  
Attentional System ◽  
Series Of Experiments

<p>People are constantly confronted by a barrage of visual information. Visual attention is the crucial mechanism which selects for further processing, subsets of information which are most behaviourally relevant, allowing us to function effectively within our everyday environment. This thesis explored how semantic information (i.e., information which has meaning) encountered within the environment influences the selective orienting of visual attention. Past research has shown semantic information does affect the orienting of attention, but the processes by which it does so remain unclear. The extent of semantic influence on the visual attention system was determined by parsing visual orienting into the tractable components of covert and overt orienting, and capture and hold process stages therein. This thesis consisted of a series of experiments which were designed, utilising well- established paradigms and semantic manipulations in concert with eye-tracking techniques, to test whether the capture and hold of either overt or covert forms of visual attention were influenced by semantic information. Taking together the main findings across all experiments, the following conclusions were drawn. 1) Semantic information differentially influences covert and overt attentional orienting processes. 2) The capture and hold of covert attention is generally uninfluenced by semantic information. 3) Semantic information briefly encountered in the environment can facilitate or prime action independent of covert attentional orienting.4) Overt attention can be both preferentially captured and held by semantically salient information encountered in visual environments. The visual attentional system thus appears to have a complex relationship with semantic information encountered in the visual environment. Semantic information has a differential influence on selective orienting processes that depends on the form of orienting employed and a range of circumstances under which attentional selection takes place.</p>

scholarly journals Semantic Influences on Overt and Covert Visual Attention

2021 ◽  
Author(s):  
◽  
Matthew David Weaver
Keyword(s):  
Visual Attention ◽  
Visual Information ◽  
Semantic Information ◽  
Past Research ◽  
Covert Attention ◽  
Attentional Orienting ◽  
Covert Visual Attention ◽  
Visual Orienting ◽  
Attentional System ◽  
Series Of Experiments

<p>People are constantly confronted by a barrage of visual information. Visual attention is the crucial mechanism which selects for further processing, subsets of information which are most behaviourally relevant, allowing us to function effectively within our everyday environment. This thesis explored how semantic information (i.e., information which has meaning) encountered within the environment influences the selective orienting of visual attention. Past research has shown semantic information does affect the orienting of attention, but the processes by which it does so remain unclear. The extent of semantic influence on the visual attention system was determined by parsing visual orienting into the tractable components of covert and overt orienting, and capture and hold process stages therein. This thesis consisted of a series of experiments which were designed, utilising well- established paradigms and semantic manipulations in concert with eye-tracking techniques, to test whether the capture and hold of either overt or covert forms of visual attention were influenced by semantic information. Taking together the main findings across all experiments, the following conclusions were drawn. 1) Semantic information differentially influences covert and overt attentional orienting processes. 2) The capture and hold of covert attention is generally uninfluenced by semantic information. 3) Semantic information briefly encountered in the environment can facilitate or prime action independent of covert attentional orienting.4) Overt attention can be both preferentially captured and held by semantically salient information encountered in visual environments. The visual attentional system thus appears to have a complex relationship with semantic information encountered in the visual environment. Semantic information has a differential influence on selective orienting processes that depends on the form of orienting employed and a range of circumstances under which attentional selection takes place.</p>

Covert visual attention in children with attention deficit hyperactivity disorder: Evidence for developmental immaturity?

1995 ◽  
Vol 7 (2) ◽  
pp. 351-367 ◽  
Author(s):  
Deborah A. Pearson ◽  
Laura S. Yaffee ◽  
Katherine A. Loveland ◽  
Amy M. Norton
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Visual Attention ◽  
Attention Deficit ◽  
Covert Attention ◽  
Adhd Group ◽  
Time Intervals ◽  
Children With Adhd ◽  
Hyperactivity Disorder ◽  
Attention Skills ◽  
Covert Visual Attention

AbstractShifts in covert visual attention were compared in children with and without Attention Deficit Hyperactivity Disorder (ADHD) to determine if children with ADHD have developmental immaturities in covert attention, relative to their non-ADHD peers. Children were told to orient attention to a central fixation point and were then cued, by both central and peripheral cues, to direct their attention to either the left or right peripheral fields. Following variable time intervals, the target appeared and reaction times and errors were recorded. Although performance of all subjects showed faciliation when attention was directed by valid cues and inhibition when attention was directed by invalid cues, the performance of children with ADHD was far more disrupted when their attention was misled by invalid cues, especially at longer intervals. This inconsistency was reflected in significantly higher error rates in the ADHD group. They also showed a pattern of attentional “waxing and waning” in performance over longer time intervals that has been previously found in auditory attention switching over time within trials in children with ADHD. Overall, results are inconsistent with developmentally immature covert attention skills in ADHD. Findings are discussed in terms of the concept of global “developmental immaturity” in the attention skills of children with ADHD.

scholarly journals Brain regions modulated during covert visual attention in the macaque

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Amarender R. Bogadhi ◽  
Anil Bollimunta ◽  
David A. Leopold ◽  
Richard J. Krauzlis
Keyword(s):  
Visual Attention ◽  
Brain Regions ◽  
Covert Visual Attention

scholarly journals Photochemically Induced Cortical Infarction in the Rat. 1. Time Course of Hemodynamic Consequences

1986 ◽  
Vol 6 (2) ◽  
pp. 184-194 ◽  
Author(s):  
W. Dalton Dietrich ◽  
Myron D. Ginsberg ◽  
Raul Busto ◽  
Brant D. Watson
Keyword(s):  
Time Course ◽  
Green Light ◽  
Brain Structures ◽  
Brain Regions ◽  
Repeated Measurements ◽  
Consistent Pattern ◽  
Subcortical Structures ◽  
Systemic Injection ◽  
Cortical Infarction ◽  
Cortical Regions

Alterations in local CBF (LCBF) were assessed autoradiographically in the rat at several time points following photochemically induced cortical infarction. Cortical infarction of consistent size and location was produced by irradiating the brain with green light through the intact skull for 20 min following the systemic injection of rose bengal. A consistent pattern of altered LCBF was recorded in both ipsilateral and contralateral brain regions over the course of the study. At 30 min, a severely ischemic zone surrounded by regions of cortical hyperemia was apparent. LCBF was also depressed relative to control values in ipsilateral cortical regions remote from the irradiated area, while contralateral cortical structures were mildly hyperemic. By 4 h, the zone of severe ischemia had enlarged and its margins were no longer hyperemic. Ipsilateral cortical and some subcortical structures demonstrated significantly depressed levels of LCBF. At 5 days, LCBF throughout both ipsilateral and contralateral cortices was depressed compared with control values. By 15 days, LCBF had returned to control levels in most brain structures shown histopathologically not to be irreversibly damaged. The temporal sequence and magnitude of these hemodynamic alterations are consistent with findings in clinical studies in which repeated measurements of CBF have been carried out in patients with acute stroke. The ability to produce a cortical infarct that results in a consistent pattern of altered CBF should facilitate the investigation of stroke mechanisms responsible for these hemodynamic abnormalities.

Topography of Covert Visual Attention in Human Superior Colliculus

2010 ◽  
Vol 104 (6) ◽  
pp. 3074-3083 ◽  
Author(s):  
Sucharit Katyal ◽  
Samir Zughni ◽  
Clint Greene ◽  
David Ress
Keyword(s):  
High Resolution ◽  
Visual Attention ◽  
Superior Colliculus ◽  
Discrimination Task ◽  
Visual Stimulation ◽  
Depth Map ◽  
Covert Attention ◽  
Full Field ◽  
Covert Visual Attention ◽  
Speed Discrimination

Experiments were performed to examine the topography of covert visual attention signals in human superior colliculus (SC), both across its surface and in its depth. We measured the retinotopic organization of SC to direct visual stimulation using a 90° wedge of moving dots that slowly rotated around fixation. Subjects ( n = 5) were cued to perform a difficult speed-discrimination task in the rotating region. To measure the retinotopy of covert attention, we used a full-field array of similarly moving dots. Subjects were cued to perform the same speed-discrimination task within a 90° wedge-shaped region, and only the cue rotated around fixation. High-resolution functional magnetic resonance imaging (fMRI, 1.2 mm voxels) data were acquired throughout SC. These data were then aligned to a high-resolution T1-weighted reference volume. The SC was segmented in this volume so that the surface of the SC could be computationally modeled and to permit calculation of a depth map for laminar analysis. Retinotopic maps were obtained for both direct visual stimulation and covert attention. These maps showed a similar spatial distribution to visual stimulation maps observed in rhesus macaque and were in registration with each other. Within the depth of SC, both visual attention and stimulation produced activity primarily in the superficial and intermediate layers, but stimulation activity extended significantly more deeply than attention.

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