scholarly journals The Influence of Distractors on Saccade-Target Selection: Saccade Trajectory Effects

2008 ◽  
Vol 2 (3) ◽  
Author(s):  
Robin Walker ◽  
Eugene McSorley
Keyword(s):  
Target Selection ◽  
Saccade Target ◽  
Competitive Balance ◽  
Distractor Stimulus ◽  
Natural Tendency ◽  
Saccade Trajectory

It has long been known that the path (trajectory) taken by the eye to land on a target is rarely straight (Yarbus, 1967). Furthermore, the magnitude and direction of this natural tendency for curvature can be modulated by the presence of a competing distractor stimulus presented along with the saccade target. The distractor-related modulation of saccade trajectories provides a subtle measure of the underlying competitive processes involved in saccade target selection. Here we review some of our own studies into the effects distractors have on saccade trajectories, which can be regarded as a way of probing the competitive balance between target and distractor salience.

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.

Coordination of Smooth Pursuit and Saccade Target Selection in Monkeys

2007 ◽  
Vol 98 (4) ◽  
pp. 2206-2214 ◽  
Author(s):  
Gilbert R. Case ◽  
Vincent P. Ferrera
Keyword(s):  
Smooth Pursuit ◽  
Target Selection ◽  
Saccade Target ◽  
Target Color ◽  
Smooth Pursuit Eye Movements ◽  
Moving Targets ◽  
Neural Signals ◽  
Pursuit Eye Movements ◽  
Selection For ◽  
Selection Signal

The coordination of saccadic and smooth pursuit eye movements in macaque monkeys was investigated using a target selection paradigm with two moving targets crossing at a center fixation point. A task in which monkeys selected a target based on its color was used to test the hypothesis that common neural signals underlie target selection for pursuit and saccades, as well as testing whether target selection signals are available to the saccade and pursuit systems simultaneously or sequentially. Several combinations of target color, speed, and direction were used. In all cases, smooth pursuit was highly selective for the rewarded target before any saccade occurred. On >80% of the trials, the saccade was directed toward the same target as both pre- and postsaccadic pursuit. The results favor a model in which a shared target selection signal is simultaneously available to both the saccade and pursuit systems, rather than a sequential model.

Target Selection for Saccadic Eye Movements: Direction-Selective Visual Responses in the Superior Colliculus

2001 ◽  
Vol 86 (5) ◽  
pp. 2527-2542 ◽  
Author(s):  
Gregory D. Horwitz ◽  
William T. Newsome
Keyword(s):  
Superior Colliculus ◽  
Eye Movement ◽  
Discrimination Task ◽  
Visual Motion ◽  
Target Selection ◽  
Small Population ◽  
Saccade Target ◽  
Visual Responses ◽  
Direction Discrimination ◽  
Deep Layers

We investigated the role of the superior colliculus (SC) in saccade target selection in rhesus monkeys who were trained to perform a direction-discrimination task. In this task, the monkey discriminated between opposed directions of visual motion and indicated its judgment by making a saccadic eye movement to one of two visual targets that were spatially aligned with the two possible directions of motion in the display. Thus the neural circuits that implement target selection in this task are likely to receive directionally selective visual inputs and be closely linked to the saccadic system. We therefore studied prelude neurons in the intermediate and deep layers of the SC that can discharge up to several seconds before an impending saccade, indicating a relatively high-level role in saccade planning. We used the direction-discrimination task to identify neurons whose prelude activity “predicted” the impending perceptual report several seconds before the animal actually executed the operant eye movement; these “choice predicting” cells comprised ∼30% of the neurons we encountered in the intermediate and deep layers of the SC. Surprisingly, about half of these prelude cells yielded direction-selective responses to our motion stimulus during a passive fixation task. In general, these neurons responded to motion stimuli in many locations around the visual field including the center of gaze where the visual discriminanda were positioned during the direction-discrimination task. Preferred directions generally pointed toward the location of the movement field of the SC neuron in accordance with the sensorimotor demands of the discrimination task. Control experiments indicate that the directional responses do not simply reflect covertly planned saccades. Our results indicate that a small population of SC prelude neurons exhibits properties appropriate for linking stimulus cues to saccade target selection in the context of a visual discrimination task.

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