scholarly journals Inhibition of Return Impairs Phosphene Detection

2012 ◽  
Vol 24 (11) ◽  
pp. 2262-2267 ◽  
Author(s):  
Daniel T. Smith ◽  
Keira Ball ◽  
Amanda Ellison
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Inhibition Of Return ◽  
Visual Exploration ◽  
Extrastriate Cortex ◽  
Neural Signals ◽  
Extrastriate Visual Cortex ◽  
Visual Areas ◽  
Target Locations ◽  
Site Of Stimulation

Efficient visual exploration requires the ability to select possible target locations via spatial attention and to deselect previously inspected locations via inhibition of return (IOR). Although a great deal is known about the effects of spatial attention on processing in visual cortex, much less is known about the effects of IOR on early visual areas. One possibility is that IOR acts in an opposite way to spatial attention, such that, whereas spatial attention enhances target related neural signals in visual cortex, IOR suppress target-related signals. Using a novel dual-coil TMS protocol, we found that IOR reduced the probability of detecting a TMS-induced phosphene in extrastriate cortex (V5). Specifically, a nonpredictive spatial precue presented 500 or 800 msec before stimulation significantly reduced the probability of detecting a phosphene when the precue appeared contralaterally to the site of stimulation (i.e., ipsilaterally to the potential location of the phosphene), compared with ipsilaterally or centrally presented cues. This result demonstrates that IOR facilitates visual exploration by directly affecting the strength of target-related signals in extrastriate visual cortex. This result is consistent with neurophysiological models of attention, which postulate that IOR modulates perception by biasing competition between sensory representations.

scholarly journals Dissociated mean and functional connectivity BOLD signals in visual cortex during eyes closed and fixation

2012 ◽  
Vol 108 (9) ◽  
pp. 2363-2372 ◽  
Author(s):  
Mark McAvoy ◽  
Linda Larson-Prior ◽  
Marek Ludwikow ◽  
Dongyang Zhang ◽  
Abraham Z. Snyder ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Functional Connectivity ◽  
Primary Visual Cortex ◽  
Blood Oxygen Level Dependent ◽  
Extrastriate Cortex ◽  
Connected Components ◽  
Bold Signal ◽  
Thalamic Nuclei ◽  
Eyes Closed ◽  
Visual Areas

We investigated the effects of resting state type on blood oxygen level-dependent (BOLD) signal and functional connectivity in two paradigms: participants either alternated between fixation and eyes closed or maintained fixation or eyes closed throughout each scan. The BOLD signal and functional connectivity of lower and higher tiers of the visual cortical hierarchy were found to be differentially modulated during eyes closed versus fixation. Fixation was associated with greater mean BOLD signals in primary visual cortex and lower mean BOLD signals in extrastriate visual areas than periods of eyes closed. In addition, analysis of thalamocortical functional connectivity during scans in which participants maintained fixation showed synchronized BOLD fluctuations between those thalamic nuclei whose mean BOLD signal was systematically modulated during alternating epochs of eyes closed and fixation, primary visual cortex and the attention network, while during eyes closed negatively correlated fluctuations were seen between the same thalamic nuclei and extrastriate visual areas. Finally, in all visual areas the amplitude of spontaneous BOLD fluctuations was greater during eyes closed than during fixation. The dissociation between early and late tiers of visual cortex, which characterizes both mean and functionally connected components of the BOLD signal, may depend on the reorganization of thalamocortical networks. Since dissociated changes in local blood flow also characterize transitions between different stages of sleep and wakefulness (Braun AR, Balkin TJ, Wesenten NJ, Gwadry F, Carson RE, Varga M, Baldwin P, Belenky G, Herscovitch P. Science 279: 91–95, 1998), our results suggest that dissociated endogenous neural activity in primary and extrastriate cortex may represent a general aspect of brain function.

Reward- and Attention-related Biasing of Sensory Selection in Visual Cortex

2014 ◽  
Vol 26 (5) ◽  
pp. 1049-1065 ◽  
Author(s):  
Antje Buschschulte ◽  
Carsten N. Boehler ◽  
Hendrik Strumpf ◽  
Christian Stoppel ◽  
Hans-Jochen Heinze ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Target Object ◽  
Extrastriate Cortex ◽  
Brain Response ◽  
Top Down ◽  
Extrastriate Visual Cortex ◽  
Response Enhancement ◽  
Irrelevant Color ◽  
Task Irrelevant ◽  
Attention To Task

Attention to task-relevant features leads to a biasing of sensory selection in extrastriate cortex. Features signaling reward seem to produce a similar bias, but how modulatory effects due to reward and attention relate to each other is largely unexplored. To address this issue, it is critical to separate top–down settings defining reward relevance from those defining attention. To this end, we used a visual search paradigm in which the target's definition (attention to color) was dissociated from reward relevance by delivering monetary reward on search frames where a certain task-irrelevant color was combined with the target-defining color to form the target object. We assessed the state of neural biasing for the attended and reward-relevant color by analyzing the neuromagnetic brain response to asynchronously presented irrelevant distractor probes drawn in the target-defining color, the reward-relevant color, and a completely irrelevant color as a reference. We observed that for the prospect of moderate rewards, the target-defining color but not the reward-relevant color produced a selective enhancement of the neuromagnetic response between 180 and 280 msec in ventral extrastriate visual cortex. Increasing reward prospect caused a delayed attenuation (220–250 msec) of the response to reward probes, which followed a prior (160–180 msec) response enhancement in dorsal ACC. Notably, shorter latency responses in dorsal ACC were associated with stronger attenuation in extrastriate visual cortex. Finally, an analysis of the brain response to the search frames revealed that the presence of the reward-relevant color in search distractors elicited an enhanced response that was abolished after increasing reward size. The present data together indicate that when top–down definitions of reward relevance and attention are separated, the behavioral significance of reward-associated features is still rapidly coded in higher-level cortex areas, thereby commanding effective top–down inhibitory control to counter a selection bias for those features in extrastriate visual cortex.

scholarly journals Attending to What and Where: Background Connectivity Integrates Categorical and Spatial Attention

2018 ◽  
Vol 30 (9) ◽  
pp. 1281-1297 ◽  
Author(s):  
Alexa Tompary ◽  
Naseem Al-Aidroos ◽  
Nicholas B. Turk-Browne
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Temporal Cortex ◽  
Relevant Information ◽  
Neural Basis ◽  
Attentional Modulation ◽  
Temporal Correlations ◽  
Visual Areas ◽  
Early Visual Cortex ◽  
Ventral Temporal Cortex

Top–down attention prioritizes the processing of goal-relevant information throughout visual cortex based on where that information is found in space and what it looks like. Whereas attentional goals often have both spatial and featural components, most research on the neural basis of attention has examined these components separately. Here we investigated how these attentional components are integrated by examining the attentional modulation of functional connectivity between visual areas with different selectivity. Specifically, we used fMRI to measure temporal correlations between spatially selective regions of early visual cortex and category-selective regions in ventral temporal cortex while participants performed a task that benefitted from both spatial and categorical attention. We found that categorical attention modulated the connectivity of category-selective areas, but only with retinotopic areas that coded for the spatially attended location. Similarly, spatial attention modulated the connectivity of retinotopic areas only with the areas coding for the attended category. This pattern of results suggests that attentional modulation of connectivity is driven both by spatial selection and featural biases. Combined with exploratory analyses of frontoparietal areas that track these changes in connectivity among visual areas, this study begins to shed light on how different components of attention are integrated in support of more complex behavioral goals.

scholarly journals A twisted visual field map in the primate cortex predicted by topographic continuity

2019 ◽  
Author(s):  
Hsin-Hao Yu ◽  
Declan P. Rowley ◽  
Nicholas S.C. Price ◽  
Marcello G.P. Rosa ◽  
Elizabeth Zavitz
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Receptive Fields ◽  
Electrode Array ◽  
Extrastriate Cortex ◽  
Complex Type ◽  
Retinotopic Maps ◽  
Visual Areas ◽  
Array Recordings ◽  
Retinotopic Map

AbstractAdjacent neurons in visual cortex have overlapping receptive fields within and across area boundaries, an arrangement which is theorized to minimize wiring cost. This constraint is thought to create retinotopic maps of opposing field sign (mirror and non-mirror representations of the visual field) in adjacent visual areas, a concept which has become central in current attempts to subdivide the cortex. We modelled a realistic developmental scenario in which adjacent areas do not mature simultaneously, but need to maintain topographic continuity across their borders. This showed that the same mechanism that is hypothesized to maintain topographic continuity within each area can lead to a more complex type of retinotopic map, consisting of sectors with opposing field sign within a same area. Using fully quantitative electrode array recordings, we then demonstrate that this type of map exists in the primate extrastriate cortex.

scholarly journals Attending to what and where: Background connectivity integrates categorical and spatial attention

2017 ◽  
Author(s):  
Alexa Tompary ◽  
Naseem Al-Aidroos ◽  
Nicholas B. Turk-Browne
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Temporal Cortex ◽  
Relevant Information ◽  
Neural Basis ◽  
Attentional Modulation ◽  
Temporal Correlations ◽  
Visual Areas ◽  
Early Visual Cortex ◽  
Ventral Temporal Cortex

AbstractTop-down attention prioritizes the processing of goal-relevant information throughout visual cortex, based on where that information is found in space and what it looks like. Whereas attentional goals often have both spatial and featural components, most research on the neural basis of attention has examined these components separately. This may reflect the fact that attention is typically studied in individual visual areas that preferentially code for either spatial locations or particular features. Here we investigated how these attentional components are integrated by examining the attentional modulation of functional connectivity between visual areas with different selectivity. Specifically, we used fMRI to measure temporal correlations between spatially-selective regions of early visual cortex and category-selective regions in ventral temporal cortex while participants performed a task that benefitted from both spatial and categorical attention. We found that categorical attention modulated the connectivity of category-selective areas, but only with retinotopic areas that coded for the spatially attended location. The reverse was not true, however, with spatial attention modulating the connectivity of retinotopic areas with category-selective areas coding for both attended and unattended features. This pattern of results suggests that attentional modulation of connectivity is dominated by spatial selection, which in turn gates featural biases. Combined with exploratory analyses of frontoparietal areas that track these changes in connectivity among visual areas, this study begins to shed light on how different components of attention are integrated in support of more complex behavioral goals.

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.

scholarly journals Cholinergic manipulations affect sensory responses but not attentional enhancement in macaque MT

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Vera Katharina Veith ◽  
Cliodhna Quigley ◽  
Stefan Treue
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Rhesus Monkeys ◽  
Cell Activity ◽  
Extrastriate Cortex ◽  
Attentional Modulation ◽  
Cellular Mechanisms ◽  
Attention Task ◽  
Sensory Responses ◽  
Cholinergic Effect

Abstract Background Attentional modulation in the visual cortex of primates is characterized by multiplicative changes of sensory responses with changes in the attentional state of the animal. The cholinergic system has been linked to such gain changes in V1. Here, we aim to determine if a similar link exists in macaque area MT. While rhesus monkeys performed a top-down spatial attention task, we locally injected a cholinergic agonist or antagonist and recorded single-cell activity. Results Although we confirmed cholinergic influences on sensory responses, there was no additional cholinergic effect on the attentional gain changes. Neither a muscarinic blockage nor a local increase in acetylcholine led to a significant change in the magnitude of spatial attention effects on firing rates. Conclusions This suggests that the cellular mechanisms of attentional modulation in the extrastriate cortex cannot be directly inferred from those in the primary visual cortex.

scholarly journals Retinotopic organization of visual cortex in human infants

2020 ◽  
Author(s):  
C. T. Ellis ◽  
T. S. Yates ◽  
L. J. Skalaban ◽  
V. R. Bejjanki ◽  
M. J. Arcaro ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Extrastriate Cortex ◽  
Human Infants ◽  
Early Maturation ◽  
Retinotopic Mapping ◽  
Retinotopic Maps ◽  
Spatial Frequencies ◽  
Visual Areas ◽  
Retinotopic Organization ◽  
Perceptual Abilities

AbstractVision develops rapidly during infancy, yet how visual cortex is organized during this period is unclear. One possibility is that the retinotopic organization of visual cortex emerges gradually as perceptual abilities improve. This may result in a hierarchical maturation of visual areas from striate to extrastriate cortex. Another possibility is that retinotopic organization is present from early infancy. This early maturation of area boundaries and tuning could scaffold further developmental changes. Here we test the functional maturity of infant visual cortex by performing retinotopic mapping with fMRI. Infants aged 5–23 months had retinotopic maps, with alternating preferences for vertical and horizontal meridians indicative of area boundaries from V1 to V4, and an orthogonal gradient of preferences from high to low spatial frequencies indicative of growing receptive field sizes. Although present in the youngest infants, these retinotopic maps showed subtle agerelated changes, suggesting that early maturation undergoes continued refinement.

Face recognition in human extrastriate cortex

1994 ◽  
Vol 71 (2) ◽  
pp. 821-825 ◽  
Author(s):  
T. Allison ◽  
H. Ginter ◽  
G. McCarthy ◽  
A. C. Nobre ◽  
A. Puce ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Face Recognition ◽  
Visual Cortex ◽  
Negative Potential ◽  
The Other ◽  
Extrastriate Cortex ◽  
Extrastriate Visual Cortex ◽  
Left And Right ◽  
Stimulation Of

1. Twenty-four patients with electrodes chronically implanted on the surface of extrastriate visual cortex viewed faces, equiluminant scrambled faces, cars, scrambled cars, and butterflies. 2. A surface-negative potential, N200, was evoked by faces but not by the other categories of stimuli. N200 was recorded only from small regions of the left and right fusiform and inferior temporal gyri. Electrical stimulation of the same region frequently produced a temporary inability to name familiar faces. 3. The results suggest that discrete regions of inferior extrastriate visual cortex, varying in location between individuals, are specialized for the recognition of faces. These "face modules" appear to be intercalated among other functionally specific small regions.

Stimulation of the Human Frontal Eye Fields Modulates Sensitivity of Extrastriate Visual Cortex

2006 ◽  
Vol 96 (2) ◽  
pp. 941-945 ◽  
Author(s):  
Juha Silvanto ◽  
Nilli Lavie ◽  
Vincent Walsh
Keyword(s):  
Visual Cortex ◽  
Spatial Organization ◽  
Extrastriate Cortex ◽  
Frontal Eye Fields ◽  
Top Down ◽  
Extrastriate Visual Cortex ◽  
Phosphene Threshold ◽  
The Right ◽  
Visual Area Mt ◽  
Stimulation Of

The precise role of frontal eye fields (FEF) in vision independent of their role in eye movements remains a matter of debate. One proposal is that the FEF exert top-down influences on the extrastriate visual cortex prior to eye movement preparation. Here we establish, by use of transcranial magnetic stimulation (TMS), that activity in the human FEFs has a direct effect on the sensitivity of extrastriate visual area MT/V5, and that the spatial organization of this top-down effect is lateralized in the human brain. We show that phosphene threshold—the TMS intensity required to elicit a visual perception—for MT/V5 stimulation changes as a function of the delay between the application of TMS over FEF and MT/V5. The effects were specific to the location and time of stimulation. Stimulation of FEF 20–40 ms prior to stimulation of MT/V5 decreased the intensity of MT/V5 stimulation required to elicit phosphenes: TMS of the right FEF changed the sensitivity of left and right MT/V5 whereas TMS of the left FEF changed the sensitivity only of the left MT/V5. Thus, the sensitivity of human extrastriate cortex is modulated by activity in the FEF.

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