Concurrent TMS-fMRI and Psychophysics Reveal Frontal Influences on Human Retinotopic Visual Cortex

Ruff, Christian C.; Blankenburg, Felix; Bjoertomt, Otto; Bestmann, Sven; Freeman, Elliot; Haynes, John­–Dylan; Rees, Geraint; Josephs, Oliver; Deichmann, Ralf; Driver, Jon

doi:10.1016/j.cub.2006.06.057

Cited by 491 publications

(474 citation statements)

References 59 publications

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“…In addition, reversible inactivation of the SC produces deficits in target selection that cannot be attributed to a purely visual or motor impairment (37). Consistent with neurophysiological studies in monkeys, transcranial magnetic stimulation experiments provide causal evidence that the attentional role of the FEF is conserved in humans (38)(39)(40)(41)(42)(43). Finally, studies in the barn owl have found that microstimulation of gaze-control circuits homologous with primate FEF produces space-specific modulation of auditory responses (44).…”

Section: Discussionmentioning

confidence: 57%

Rapid enhancement of visual cortical response discriminability by microstimulation of the frontal eye field

Armstrong

Moore²

2007

Proc. Natl. Acad. Sci. U.S.A.

176

119

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Visual attention provides a means of selecting among the barrage of information reaching the retina and of enhancing the perceptual discriminability of relevant stimuli. Neurophysiological studies in monkeys and functional imaging studies in humans have demonstrated neural correlates of these perceptual improvements in visual cortex during attention. Importantly, voluntary attention improves the discriminability of visual cortical responses to relevant stimuli. Recent work aimed at identifying sources of attentional modulation has implicated the frontal eye field (FEF) in driving spatial attention. Subthreshold microstimulation of the FEF enhances the responses of area V4 neurons to spatially corresponding stimuli. However, it is not known whether these enhancements include improved visual-response discriminability, a hallmark of voluntary attention. We used receiver-operator characteristic analysis to quantify how well V4 responses discriminated visual stimuli and examined how discriminability was affected by FEF microstimulation. Discriminability of responses to stable visual stimuli decayed over time but was transiently restored after microstimulation of the FEF. As observed during voluntary attention, the enhancement resulted only from changes in the magnitude of V4 responses and not in the relationship between response magnitude and variance. Enhanced response discriminability was apparent immediately after microstimulation and was reliable within 40 ms of microstimulation onset, indicating a direct influence of FEF stimulation on visual representations. These results contribute to the mounting evidence that saccade-related signals are a source of spatial attentive selection.cognition ͉ gain control ͉ oculomotor ͉ prefrontal cortex ͉ visual perception C overt visual attention selectively enhances relevant signals from among the flood of information that enters the eye. Perception of attended stimuli is enhanced in a variety of ways (1-3), but in general discrimination of attended stimuli is improved (4). Neurophysiological studies in monkeys and functional imaging studies in humans have demonstrated neural correlates of these perceptual improvements in visual cortex during attention (5-7). Recent work has implicated saccaderelated circuits in driving modulations of visual processing during spatial attention. Specifically, subthreshold microstimulation of the frontal eye field (FEF), an area involved in the control of voluntary saccadic eye movements (8, 9), improves performance on an attention task (10, 11) and transiently enhances visual responses in extrastriate area V4 (12, 13). It is known that voluntary attention improves the discriminability of V4 neuronal responses (14,15) and that the enhanced discriminability results from selective changes in the magnitude of visual responses but not in their reliability (16). Although the effects of FEF microstimulation on V4 responses mirror those of voluntary attention in some respects (12, 13), how FEF microstimulation affects response discriminability and reli...

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Section: Discussionmentioning

confidence: 57%

Rapid enhancement of visual cortical response discriminability by microstimulation of the frontal eye field

Armstrong

Moore²

2007

Proc. Natl. Acad. Sci. U.S.A.

176

119

View full text Add to dashboard Cite

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“…In that sense it is closely related to the concept of densely connected "rich-club" nodes (36). Given these topological properties and its location primarily in frontal cortex, the core appears to be in an ideal position to exert control over the periphery (4,30,40,41). We interpret the increased core closeness of taskrelevant areas to reflect an enhancement in bidirectional information flow.…”

Section: Discussionmentioning

confidence: 75%

Predicting errors from reconfiguration patterns in human brain networks

Ekman

Derrfuß

Tittgemeyer

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

157

143

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Task preparation is a complex cognitive process that implements anticipatory adjustments to facilitate future task performance.Little is known about quantitative network parameters governing this process in humans. Using functional magnetic resonance imaging (fMRI) and functional connectivity measurements, we show that the large-scale topology of the brain network involved in task preparation shows a pattern of dynamic reconfigurations that guides optimal behavior. This network could be decomposed into two distinct topological structures, an error-resilient core acting as a major hub that integrates most of the network's communication and a predominantly sensory periphery showing more flexible network adaptations. During task preparation, core-periphery interactions were dynamically adjusted. Task-relevant visual areas showed a higher topological proximity to the network core and an enhancement in their local centrality and interconnectivity. Failure to reconfigure the network topology was predictive for errors, indicating that anticipatory network reconfigurations are crucial for successful task performance. On the basis of a unique network decoding approach, we also develop a general framework for the identification of characteristic patterns in complex networks, which is applicable to other fields in neuroscience that relate dynamic network properties to behavior. graph theory | attention | cognitive control T he human brain forms a highly complex network that is organized into a large number of specialized regions. During goal-directed behavior, like the preparation of an upcoming task, relevant cortical regions are anticipatorily modulated (1-5), which has been shown to facilitate the detection and analysis of task-relevant stimuli (6-13).However, little is known about how these task-specific adjustments are integrated across distinct brain regions and how preparatory mechanisms are reflected in a large-scale network topology (14-16). It has been shown that attention can modulate interarea correlations between distant cortical regions, independent from changes in regional blood flow (17-19). However, these studies were usually limited to a small selection of cortical regions (2,7,15,(18)(19)(20). With recent developments in functional connectivity analysis, it has become possible to study the role of large-scale networks for cognitive processing and to quantify network properties using global and local graph theoretical measures (21-26).On the one hand, task preparation involves dynamic adjustments in regions that carry out computations that are specific to a given task. On the other hand, it also requires the stable maintenance of task goals (7) and reconfigurations of the network based on these goals. Given these characteristics and the organization of brain networks into modules with distinct functional properties (27, 28), we hypothesized that task-specific processes, whose involvement varies from trial to trial, are reflected in dynamic adjustments of more peripheral components of the brain network. We...

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“…Combining electrophysiological, fMRI, TMS and lesion studies will produce results that are much more reliable than those which can be obtained from any one of these approaches in isolation (e.g. [119][120][121]). …”

Section: Discussionmentioning

confidence: 99%

The neuropsychology of face perception: beyond simple dissociations and functional selectivity

Atkinson

Adolphs

2011

Phil. Trans. R. Soc. B

153

111

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Face processing relies on a distributed, patchy network of cortical regions in the temporal and frontal lobes that respond disproportionately to face stimuli, other cortical regions that are not even primarily visual (such as somatosensory cortex), and subcortical structures such as the amygdala. Higher-level face perception abilities, such as judging identity, emotion and trustworthiness, appear to rely on an intact face-processing network that includes the occipital face area (OFA), whereas lower-level face categorization abilities, such as discriminating faces from objects, can be achieved without OFA, perhaps via the direct connections to the fusiform face area (FFA) from several extrastriate cortical areas. Some lesion, transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) findings argue against a strict feed-forward hierarchical model of face perception, in which the OFA is the principal and common source of input for other visual and non-visual cortical regions involved in face perception, including the FFA, faceselective superior temporal sulcus and somatosensory cortex. Instead, these findings point to a more interactive model in which higher-level face perception abilities depend on the interplay between several functionally and anatomically distinct neural regions. Furthermore, the nature of these interactions may depend on the particular demands of the task. We review the lesion and TMS literature on this topic and highlight the dynamic and distributed nature of face processing.

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Concurrent TMS-fMRI and Psychophysics Reveal Frontal Influences on Human Retinotopic Visual Cortex

Cited by 491 publications

References 59 publications

Rapid enhancement of visual cortical response discriminability by microstimulation of the frontal eye field

Rapid enhancement of visual cortical response discriminability by microstimulation of the frontal eye field

Predicting errors from reconfiguration patterns in human brain networks

The neuropsychology of face perception: beyond simple dissociations and functional selectivity

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