scholarly journals Salience by Competitive and Recurrent Interactions: Bridging Neural Spiking and Computation

2021 ◽  
Author(s):  
Gregory Edward Cox ◽  
Thomas Palmeri ◽  
Gordon D. Logan ◽  
Philip L. Smith ◽  
Jeffrey Schall
Keyword(s):  
Decision Making ◽  
Response Times ◽  
Target Selection ◽  
Interaction Model ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Visual Neurons ◽  
Discharge Rates ◽  
Neural Spiking ◽  
Eye Field

Decisions about where to move the eyes depend on neurons in Frontal Eye Field (FEF). Movement neurons in FEF accumulate salience evidence derived from FEF visual neurons to select the location of a saccade target among distractors. How visual neurons achieve this salience representation is unknown. We present a neuro-computational model of target selection called Salience by Competitive and Recurrent Interactions (SCRI), based on the Competitive Interaction model of attentional selection and decision making (Smith & Sewell, 2013). SCRI selects targets by synthesizing localization and identification information to yield a dynamically evolving representation of salience across the visual field. SCRI accounts for neural spiking of individual FEF visual neurons, explaining idiosyncratic differences in neural dynamics with specific parameters. Many visual neurons resolve the competition between search items through feedforward inhibition between signals representing different search items, some also require lateral inhibition, and many act as recurrent gates to modulate the incoming flow of information about stimulus identity. SCRI was tested further by using simulated spiking representations of visual salience as input to the Gated Accumulator Model of FEF movement neurons (Purcell et al., 2010; Purcell, Schall, Logan, & Palmeri, 2012). Predicted saccade response times fit those observed for search arrays of different set size and different target-distractor similarity, and accumulator trajectories replicated movement neuron discharge rates. These findings offer new insights into visual decision making through converging neuro-computational constraints and provide a novel computational account of the diversity of FEF visual neurons.

scholarly journals Shape Selectivity in Primate Frontal Eye Field

2008 ◽  
Vol 100 (2) ◽  
pp. 796-814 ◽  
Author(s):  
Xinmiao Peng ◽  
Margaret E. Sereno ◽  
Amanda K. Silva ◽  
Sidney R. Lehky ◽  
Anne B. Sereno
Keyword(s):  
Functional Organization ◽  
Target Selection ◽  
Visual Stimuli ◽  
Shape Selectivity ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Gaze Shift ◽  
Match To Sample ◽  
Neurophysiological Studies ◽  
Eye Field

Previous neurophysiological studies of the frontal eye field (FEF) in monkeys have focused on its role in saccade target selection and gaze shift control. It has been argued that FEF neurons indicate the locations of behaviorally significant visual stimuli and are not inherently sensitive to specific features of the visual stimuli per se. Here, for the first time, we directly examined single cell responses to simple, two-dimensional shapes and found that shape selectivity exists in a substantial number of FEF cells during a passive fixation task or during the sample, delay (memory), and eye movement periods in a delayed match to sample (DMTS) task. Our data demonstrate that FEF neurons show sensory and mnemonic selectivity for stimulus shape features whether or not they are behaviorally significant for the task at hand. We also investigated the extent and localization of activation in the FEF using a variety of shape stimuli defined by static or dynamic cues employing functional magentic resonance imaging (fMRI) in anesthetized and paralyzed monkeys. Our fMRI results support the electrophysiological findings by showing significant FEF activation for a variety of shape stimuli and cues in the absence of attentional and motor processing. This shape selectivity in FEF is comparable to previous reports in the ventral pathway, inviting a reconsideration of the functional organization of the visual system.

scholarly journals Neurally constrained modeling of speed-accuracy tradeoff during visual search: gated accumulation of modulated evidence

2019 ◽  
Vol 121 (4) ◽  
pp. 1300-1314 ◽  
Author(s):  
Mathieu Servant ◽  
Gabriel Tillman ◽  
Jeffrey D. Schall ◽  
Gordon D. Logan ◽  
Thomas J. Palmeri
Keyword(s):  
Decision Making ◽  
Visual Search ◽  
Response Times ◽  
Frontal Eye Field ◽  
Search Performance ◽  
Model Framework ◽  
Accumulator Model ◽  
Eye Field ◽  
Speed Accuracy ◽  
Accuracy Tradeoff

Stochastic accumulator models account for response times and errors in perceptual decision making by assuming a noisy accumulation of perceptual evidence to a threshold. Previously, we explained saccade visual search decision making by macaque monkeys with a stochastic multiaccumulator model in which accumulation was driven by a gated feed-forward integration to threshold of spike trains from visually responsive neurons in frontal eye field that signal stimulus salience. This neurally constrained model quantitatively accounted for response times and errors in visual search for a target among varying numbers of distractors and replicated the dynamics of presaccadic movement neurons hypothesized to instantiate evidence accumulation. This modeling framework suggested strategic control over gate or over threshold as two potential mechanisms to accomplish speed-accuracy tradeoff (SAT). Here, we show that our gated accumulator model framework can account for visual search performance under SAT instructions observed in a milestone neurophysiological study of frontal eye field. This framework captured key elements of saccade search performance, through observed modulations of neural input, as well as flexible combinations of gate and threshold parameters necessary to explain differences in SAT strategy across monkeys. However, the trajectories of the model accumulators deviated from the dynamics of most presaccadic movement neurons. These findings demonstrate that traditional theoretical accounts of SAT are incomplete descriptions of the underlying neural adjustments that accomplish SAT, offer a novel mechanistic account of decision-making mechanisms during speed-accuracy tradeoff, and highlight questions regarding the identity of model and neural accumulators. NEW & NOTEWORTHY A gated accumulator model is used to elucidate neurocomputational mechanisms of speed-accuracy tradeoff. Whereas canonical stochastic accumulators adjust strategy only through variation of an accumulation threshold, we demonstrate that strategic adjustments are accomplished by flexible combinations of both modulation of the evidence representation and adaptation of accumulator gate and threshold. The results indicate how model-based cognitive neuroscience can translate between abstract cognitive models of performance and neural mechanisms of speed-accuracy tradeoff.

scholarly journals Saccade target selection in frontal eye field of macaque. I. Visual and premovement activation

1995 ◽  
Vol 15 (10) ◽  
pp. 6905-6918 ◽  
Author(s):  
JD Schall ◽  
DP Hanes ◽  
KG Thompson ◽  
DJ King
Keyword(s):  
Target Selection ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Eye Field

scholarly journals Frontal Eye Field Activity Before Visual Search Errors Reveals the Integration of Bottom-Up and Top-Down Salience

2005 ◽  
Vol 93 (1) ◽  
pp. 337-351 ◽  
Author(s):  
Kirk G. Thompson ◽  
Narcisse P. Bichot ◽  
Takashi R. Sato
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Target Selection ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Top Down ◽  
Bottom Up ◽  
Stimulus Response ◽  
Singleton Search ◽  
Eye Field

We investigated the saccade decision process by examining activity recorded in the frontal eye field (FEF) of monkeys performing 2 separate visual search experiments in which there were errors in saccade target choice. In the first experiment, the difficulty of a singleton search task was manipulated by varying the similarity between the target and distractors; errors were made more often when the distractors were similar to the target. On catch trials in which the target was absent the monkeys occasionally made false alarm errors by shifting gaze to one of the distractors. The second experiment was a popout color visual search task in which the target and distractor colors switched unpredictably across trials. Errors occurred most frequently on the first trial after the switch and less often on subsequent trials. In both experiments, FEF neurons selected the saccade goal on error trials, not the singleton target of the search array. Although saccades were made to the same stimulus locations, presaccadic activation and the magnitude of selection differed across trial conditions. The variation in presaccadic selective activity was accounted for by the variation in saccade probability across the stimulus–response conditions, but not by variations in saccade metrics. These results suggest that FEF serves as a saccade probability map derived from the combination of bottom-up and top-down influences. Peaks on this map represent the behavioral relevance of each item in the visual field rather than just reflecting saccade preparation. This map in FEF may correspond to the theoretical salience map of many models of attention and saccade target selection.

Neural basis of saccade target selection in frontal eye field during visual search

Nature ◽  
1993 ◽  
Vol 366 (6454) ◽  
pp. 467-469 ◽  
Author(s):  
Jeffrey D. Schall ◽  
Doug P. Hanes
Keyword(s):  
Visual Search ◽  
Target Selection ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Neural Basis ◽  
Eye Field

Neurocognitive Modeling of Perceptual Decision Making

2015 ◽  
Author(s):  
Thomas J. Palmeri ◽  
Jeffrey D. Schall ◽  
Gordon D. Logan
Keyword(s):  
Decision Making ◽  
Drift Rate ◽  
Response Times ◽  
Perceptual Processing ◽  
Mathematical Psychology ◽  
Frontal Eye Field ◽  
Perceptual Decision Making ◽  
Systems Neuroscience ◽  
Eye Field ◽  
Accumulator Models

Mathematical psychology and systems neuroscience have converged on stochastic accumulator models to explain decision making. We examined saccade decisions in monkeys while neurophysiological recordings were made within their frontal eye field. Accumulator models were tested on how well they fit response probabilities and distributions of response times to make saccades. We connected these models with neurophysiology. To test the hypothesis that visually responsive neurons represented perceptual evidence driving accumulation, we replaced perceptual processing time and drift rate parameters with recorded neurophysiology from those neurons. To test the hypothesis that movement related neurons instantiated the accumulator, we compared measures of neural dynamics with predicted measures of accumulator dynamics. Thus, neurophysiology both provides a constraint on model assumptions and data for model selection. We highlight a gated accumulator model that accounts for saccade behavior during visual search, predicts neurophysiology during search, and provides insights into the locus of cognitive control over decisions.

scholarly journals Sequential Operations Revealed by Serendipitous Feature Selectivity in Frontal Eye Field

2019 ◽  
Author(s):  
Kaleb A. Lowe ◽  
Jeffrey D. Schall
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Target Selection ◽  
Stimulus Orientation ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Eye Field ◽  
Feature Selectivity ◽  
Selection Indexes

ABSTRACTNeurons in macaque frontal eye field contribute to spatial but typically not feature selection during visual search. Using an innovative visual search task, we report a serendipitous discovery that some frontal eye field neurons can develop rapid selectivity for stimulus orientation that is used to guide gaze during a visual search task with pro-saccade and anti-saccade responses. This feature selectivity occurs simultaneously at multiple locations for all objects sharing that feature and coincides with when neurons select the singleton of a search array. This feature selectivity also reveals the distinct, subsequent operation of selecting the endpoint of the saccade in pro-saccade as well as anti-saccade trials. These results demonstrate that target selection preceding saccade preparation is composed of multiple operations. We conjecture that singleton selection indexes the allocation of attention, which can be divided, to conspicuous items. Consequently, endpoint selection indexes the focused allocation of attention to the endpoint of the saccade. These results demonstrate that saccade target selection is not a unitary process.SIGNIFICANCE STATEMENTFrontal eye field is well known to contribute to spatial selection for attention and eye movements. We discovered that some frontal eye field neurons can acquire selectivity for stimulus orientation when it guides visual search. The chronometry of neurons with and without feature selectivity reveal distinct operations accomplishing visual search.

Dynamic Dissociation of Visual Selection From Saccade Programming in Frontal Eye Field

2001 ◽  
Vol 86 (5) ◽  
pp. 2634-2637 ◽  
Author(s):  
Aditya Murthy ◽  
Kirk G. Thompson ◽  
Jeffrey D. Schall
Keyword(s):  
Visual Search ◽  
Selection Process ◽  
Frontal Eye Field ◽  
Frontal Eye Fields ◽  
Search Array ◽  
Visual Neurons ◽  
Current Location ◽  
Eye Field ◽  
Saccade Programming ◽  
Selection Of

Previous studies of visually responsive neurons in the frontal eye fields have identified a selection process preceding saccades during visual search. The goal of this experiment was to determine whether the selection process corresponds to the selection of a conspicuous stimulus or to preparation of the next saccade. This was accomplished with the use of a novel task, called search-step, in which the target of a singleton visual search array switches location with a distracter on random trials. The target step trials created a condition in which the same stimulus yielded saccades either toward or away from the target. Visually responsive neurons in frontal eye field selected the current location of the conspicuous target even when gaze shifted to the location of a distractor. This dissociation demonstrates that the selection process manifest in visual neurons in the frontal eye field may be an explicit interpretation of the image and not an obligatory saccade command.

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