Radial motion bias in macaque frontal eye field

Xiao, Qirong; Barborică, Andrei; Ferrera, Vincent P.

doi:10.1017/s0952523806231055

Cited by 43 publications

(28 citation statements)

References 57 publications

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“…Under this condition, few of the visual neurons were modulated at all and those that were did so well after SSRT. The fact that in this study some of the visual neurons responded to the replacement of the target by a distractor in their receptive field before TSRT is consistent with reports that some FEF neurons can signal stimulus features in the search array (e.g., Bichot et al 1996;Peng et al 2008;Xiao et al 2006).…”

Section: Visual Response To the Target Stepsupporting

confidence: 91%

Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation

Murthy¹,

Ray²,

Shorter³

et al. 2009

Journal of Neurophysiology

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Murthy A, Ray S, Shorter SM, Schall JD, Thompson KG. Neural control of visual search by frontal eye field: effects of unexpected target displacement on visual selection and saccade preparation. J Neurophysiol 101: 2485-2506, 2009. First published March 4, 2009 doi:10.1152/jn.90824.2008. The dynamics of visual selection and saccade preparation by the frontal eye field was investigated in macaque monkeys performing a search-step task combining the classic double-step saccade task with visual search. Reward was earned for producing a saccade to a color singleton. On random trials the target and one distractor swapped locations before the saccade and monkeys were rewarded for shifting gaze to the new singleton location. A race model accounts for the probabilities and latencies of saccades to the initial and final singleton locations and provides a measure of the duration of a covert compensation process-targetstep reaction time. When the target stepped out of a movement field, noncompensated saccades to the original location were produced when movement-related activity grew rapidly to a threshold. Compensated saccades to the final location were produced when the growth of the original movement-related activity was interrupted within target-step reaction time and was replaced by activation of other neurons producing the compensated saccade. When the target stepped into a receptive field, visual neurons selected the new target location regardless of the monkeys' response. When the target stepped out of a receptive field most visual neurons maintained the representation of the original target location, but a minority of visual neurons showed reduced activity. Chronometric analyses of the neural responses to the target step revealed that the modulation of visually responsive neurons and movement-related neurons occurred early enough to shift attention and saccade preparation from the old to the new target location. These findings indicate that visual activity in the frontal eye field signals the location of targets for orienting, whereas movement-related activity instantiates saccade preparation. I N T R O D U C T I O NTo investigate the neural basis of the decision processes of saccade target selection, we have recorded neural activity in the frontal eye field (FEF) of macaque monkeys trained to perform visual search tasks (Bichot and Schall 1999; Bichot et al.

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Section: Visual Response To the Target Stepsupporting

confidence: 91%

Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation

Murthy¹,

Ray²,

Shorter³

et al. 2009

Journal of Neurophysiology

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“…For example, single-unit recordings have shown that the FEF contains both visual and perisaccadic neurons. Visual neurons have activity that is closely linked to the onset of visual stimuli (2,(8)(9)(10), whereas perisaccadic neurons have activity that is restricted to the time immediately around the execution of saccades (2,22,23). Some measurements suggest that these cell types are discrete classes of neurons, rather than ends of a continuum (11).…”

Section: Discussionmentioning

confidence: 99%

“…Single-unit recordings have shown that a substantial fraction of FEF neurons have little or no perisaccadic activity and instead have strong, short-latency visual responses (2). These visually driven neurons can respond selectivity to different stimulus dimensions (8,9) and distinguish the behavioral relevance of stimuli in an array (10). The activity of these neurons, unlike FEF neurons with perisaccadic activity, is strongly correlated with stimulus onset and only weakly correlated with the timing of saccadic responses (11).…”

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confidence: 99%

Electrical microstimulation thresholds for behavioral detection and saccades in monkey frontal eye fields

Murphey

Maunsell

2008

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

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The frontal eye field (FEF) is involved in the transformation of visual signals into saccadic eye movements. Although it is often considered an oculomotor structure, several lines of evidence suggest that the FEF also contributes to visual perception and attention. To better understand the range of behaviors to which the FEF can contribute, we tested whether monkeys could detect activation of their FEF by electrical microstimulation with currents below those that cause eye movements. We found that stimulation of FEF neurons could almost always be detected at levels below those needed to generate saccades and that the electrical current needed for detection was highly correlated with that needed to generate a saccade. This relationship between detection and saccade thresholds can be explained if FEF neurons represent preparation to make particular saccades and subjects can be aware of such preparations without acting on them when the representation is not strong.T he primate frontal eye field (FEF) plays a well established role in the generation of saccades. Single-unit recordings have shown that many neurons in the FEF are active around the time of saccades of specific magnitude and direction and that a topographic representation of saccade vectors exists across the FEF (1). Electrical microstimulation of sites in the FEF can produce saccades of a particular vector (2). Ablating the FEF causes pronounced deficits in generating eye movements to visual targets (3). In humans, functional MRI studies have shown activity in the FEF is correlated with visually guided saccade generation (4), and transcranial magnetic stimulation (TMS) of the FEF has been shown to disrupt saccade generation (5, 6).Although the FEF is important in oculomotor control, several lines of evidence suggest that it plays a role that goes beyond the initiation and control of eye movements (7). The FEF receives visual inputs from the thalamus and shows extensive reciprocal connectivity with visual cortical areas (1). Single-unit recordings have shown that a substantial fraction of FEF neurons have little or no perisaccadic activity and instead have strong, short-latency visual responses (2). These visually driven neurons can respond selectivity to different stimulus dimensions (8, 9) and distinguish the behavioral relevance of stimuli in an array (10). The activity of these neurons, unlike FEF neurons with perisaccadic activity, is strongly correlated with stimulus onset and only weakly correlated with the timing of saccadic responses (11). Additionally, experiments using electrical microstimulation and TMS of the FEF have shown that FEF activation can produce effects that appear similar to spatial attention (7,(12)(13)(14)(15).To further explore the range of behaviors to which FEF activity can contribute, we have examined whether subjects can detect the activity of FEF neurons at levels that are too low to produce eye movements. Studies using electrical microstimulation of local sites in different areas of visual cortex (16) and somatosensory co...

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“…Favoring this hypothesis, it has been reported that FEF neurons are active during attentive tracking (Xiao et al, 2007) and that microstimulation of the FEF produces changes in the RF profile of V4 neurons (Armstrong et al, 2006). The small differences between the magnitude of the effects in outward and inward trials may relate to biases in eye movement planning toward concentrically and eccentrically moving targets (Segraves et al, 1987;Xiao et al, 2006). One issue to be addressed by future studies is whether changes in the RF or movement field profiles of FEF neurons precede the expansion of MT RFs described in our study.…”

Section: Origins Of the Modulatory Signalmentioning

confidence: 99%

Expansion of MT Neurons Excitatory Receptive Fields during Covert Attentive Tracking

Niebergall

Khayat²,

Treue³

et al. 2011

J. Neurosci.

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Primates can attentively track moving objects while keeping gaze stationary. The neural mechanisms underlying this ability are poorly understood. We investigated this issue by recording responses of neurons in area MT of two rhesus monkeys while they performed two different tasks. During the Attend-Fixation task, two moving random dot patterns (RDPs) translated across a screen at the same speed and in the same direction while the animals directed gaze to a fixation spot and detected a change in its luminance. During the Tracking task, the animals kept gaze on the fixation spot and attentively tracked the two RDPs to report a change in the local speed of one of the patterns' dots. In both conditions, neuronal responses progressively increased as the RDPs entered the neurons' receptive field (RF), peaked when they reached its center, and decreased as they translated away. This response profile was well described by a Gaussian function with its center of gravity indicating the RF center and its flanks the RF excitatory borders. During Tracking, responses were increased relative to Attend-Fixation, causing the Gaussian profiles to expand. Such increases were proportionally larger in the RF periphery than at its center, and were accompanied by a decrease in the trial-to-trial response variability (Fano factor) relative to Attend-Fixation. These changes resulted in an increase in the neurons' performance at detecting targets at longer distances from the RF center. Our results show that attentive tracking dynamically changes MT neurons' RF profiles, ultimately improving the neurons' ability to encode the tracked stimulus features.

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Radial motion bias in macaque frontal eye field

Cited by 43 publications

References 57 publications

Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation

Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation

Electrical microstimulation thresholds for behavioral detection and saccades in monkey frontal eye fields

Expansion of MT Neurons Excitatory Receptive Fields during Covert Attentive Tracking

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