scholarly journals Spatial attention during saccade decisions

2017 ◽  
Vol 118 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Donatas Jonikaitis ◽  
Anna Klapetek ◽  
Heiner Deubel

Behavioral measures of decision making are usually limited to observations of decision outcomes. In the present study, we made use of the fact that oculomotor and sensory selection are closely linked to track oculomotor decision making before oculomotor responses are made. We asked participants to make a saccadic eye movement to one of two memorized target locations and observed that visual sensitivity increased at both the chosen and the nonchosen saccade target locations, with a clear bias toward the chosen target. The time course of changes in visual sensitivity was related to saccadic latency, with the competition between the chosen and nonchosen targets resolved faster before short-latency saccades. On error trials, we observed an increased competition between the chosen and nonchosen targets. Moreover, oculomotor selection and visual sensitivity were influenced by top-down and bottom-up factors as well as by selection history and predicted the direction of saccades. Our findings demonstrate that saccade decisions have direct visual consequences and show that decision making can be traced in the human oculomotor system well before choices are made. Our results also indicate a strong association between decision making, saccade target selection, and visual sensitivity. NEW & NOTEWORTHY We show that saccadic decisions can be tracked by measuring spatial attention. Spatial attention is allocated in parallel to the two competing saccade targets, and the time course of spatial attention differs for fast-slow and for correct-erroneous decisions. Saccade decisions take the form of a competition between potential saccade goals, which is associated with spatial attention allocation to those locations.

2021 ◽  
Author(s):  
Gregory Edward Cox ◽  
Thomas Palmeri ◽  
Gordon D. Logan ◽  
Philip L. Smith ◽  
Jeffrey Schall

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.


2018 ◽  
Vol 120 (6) ◽  
pp. 3042-3062 ◽  
Author(s):  
Devin H. Kehoe ◽  
Selvi Aybulut ◽  
Mazyar Fallah

Previous behavioral and physiological research has demonstrated that as the behavioral relevance of potential saccade goals increases, they elicit more competition during target selection processing as evidenced by increased saccade curvature and neural activity. However, these effects have only been demonstrated for lower order feature singletons, and it remains unclear whether more complicated featural differences between higher order objects also elicit vector modulation. Therefore, we measured human saccades curvature elicited by distractors bilaterally flanking a target during a visual search saccade task and systematically varied subsets of features shared between the two distractors and the target, referred to as objective similarity (OS). Our results demonstrate that saccades deviated away from the distractor highest in OS to the target and that there was a linear relationship between the magnitude of saccade deviation and the number of feature differences between the most similar distractor and the target. Furthermore, an analysis of curvature over the time course of the saccade demonstrated that curvature only occurred in the first 20–30 ms of the movement. Given the multifeatural complexity of the novel stimuli, these results suggest that saccadic target selection processing involves dynamically reweighting vector representations for movement planning to several possible targets based on their behavioral relevance. NEW & NOTEWORTHY We demonstrate that small featural differences between unfamiliar, higher order object representations modulate vector weights during saccadic target selection processing. Such effects have previously only been demonstrated for familiar, simple feature singletons (e.g., color) in which features characterize entire objects. The complexity and novelty of our stimuli suggest that the oculomotor system dynamically receives visual/cognitive information processed in the higher order representational networks of the cortical visual processing hierarchy and integrates this information for saccadic movement planning.


Author(s):  
Devin Heinze Kehoe ◽  
Jennifer Lewis ◽  
Mazyar Fallah

Oculomotor target selection often requires discriminating visual features, but it remains unclear how oculomotor substrates encoding saccade vectors functionally contribute to this process. One possibility is that oculomotor vector representations (observed directly as physiological activation or inferred from behavioral interference) of potential targets are continuously re-weighted by task-relevance computed elsewhere in specialized visual modules, while an alternative possibility is that oculomotor modules utilize local featural analyses to actively discriminate potential targets. Strengthening the former account, oculomotor vector representations have longer onset latencies for ventral- (i.e., color) than dorsal-stream features (i.e., luminance), suggesting that oculomotor vector representations originate from featurally-relevant specialized visual modules. Here, we extended this reasoning by behaviorally examining whether the onset latency of saccadic interference elicited by visually complex stimuli is greater than is commonly observed for simple stimuli. We measured human saccade metrics (saccade curvature, endpoint deviations, saccade frequency, error proportion) as a function of time after abrupt distractor onset. Distractors were novel, visually complex, and had to be discriminated from targets to guide saccades. The earliest saccadic interference latency was ~110 ms, considerably longer than previous experiments, suggesting that sensory representations projected into the oculomotor system are gated to allow for sufficient featural processing to satisfy task demands. Surprisingly, initial oculomotor vector representations encoded features, as we manipulated the visual similarity between targets and distractors and observed increased vector modulation response magnitude and duration when the distractor was highly similar to the target. Oculomotor vector modulation was gradually extinguished over the time course of the experiment.


2016 ◽  
Vol 115 (2) ◽  
pp. 1071-1076 ◽  
Author(s):  
Nina M. Hanning ◽  
Donatas Jonikaitis ◽  
Heiner Deubel ◽  
Martin Szinte

Oculomotor selection, spatial task relevance, and visual working memory (WM) are described as three processes highly intertwined and sustained by similar cortical structures. However, because task-relevant locations always constitute potential saccade targets, no study so far has been able to distinguish between oculomotor selection and spatial task relevance. We designed an experiment that allowed us to dissociate in humans the contribution of task relevance, oculomotor selection, and oculomotor execution to the retention of feature representations in WM. We report that task relevance and oculomotor selection lead to dissociable effects on feature WM maintenance. In a first task, in which an object's location was encoded as a saccade target, its feature representations were successfully maintained in WM, whereas they declined at nonsaccade target locations. Likewise, we observed a similar WM benefit at the target of saccades that were prepared but never executed. In a second task, when an object's location was marked as task relevant but constituted a nonsaccade target (a location to avoid), feature representations maintained at that location did not benefit. Combined, our results demonstrate that oculomotor selection is consistently associated with WM, whereas task relevance is not. This provides evidence for an overlapping circuitry serving saccade target selection and feature-based WM that can be dissociated from processes encoding task-relevant locations.


2012 ◽  
Vol 108 (5) ◽  
pp. 1392-1402 ◽  
Author(s):  
Elsie Premereur ◽  
Wim Vanduffel ◽  
Pieter R. Roelfsema ◽  
Peter Janssen

Macaque frontal eye fields (FEF) and the lateral intraparietal area (LIP) are high-level oculomotor control centers that have been implicated in the allocation of spatial attention. Electrical microstimulation of macaque FEF elicits functional magnetic resonance imaging (fMRI) activations in area LIP, but no study has yet investigated the effect of FEF microstimulation on LIP at the single-cell or local field potential (LFP) level. We recorded spiking and LFP activity in area LIP during weak, subthreshold microstimulation of the FEF in a delayed-saccade task. FEF microstimulation caused a highly time- and frequency-specific, task-dependent increase in gamma power in retinotopically corresponding sites in LIP: FEF microstimulation produced a significant increase in LIP gamma power when a saccade target appeared and remained present in the LIP receptive field (RF), whereas less specific increases in alpha power were evoked by FEF microstimulation for saccades directed away from the RF. Stimulating FEF with weak currents had no effect on LIP spike rates or on the gamma power during memory saccades or passive fixation. These results provide the first evidence for task-dependent modulations of LFPs in LIP caused by top-down stimulation of FEF. Since the allocation and disengagement of spatial attention in visual cortex have been associated with increases in gamma and alpha power, respectively, the effects of FEF microstimulation on LIP are consistent with the known effects of spatial attention.


2010 ◽  
Vol 22 (5) ◽  
pp. 1011-1025 ◽  
Author(s):  
Andrea Facoetti ◽  
Anna Noemi Trussardi ◽  
Milena Ruffino ◽  
Maria Luisa Lorusso ◽  
Carmen Cattaneo ◽  
...  

Although the dominant approach posits that developmental dyslexia arises from deficits in systems that are exclusively linguistic in nature (i.e., phonological deficit theory), dyslexics show a variety of lower level deficits in sensory and attentional processing. Although their link to the reading disorder remains contentious, recent empirical and computational studies suggest that spatial attention plays an important role in phonological decoding. The present behavioral study investigated exogenous spatial attention in dyslexic children and matched controls by measuring RTs to visual and auditory stimuli in cued-detection tasks. Dyslexics with poor nonword decoding accuracy showed a slower time course of visual and auditory (multisensory) spatial attention compared with both chronological age and reading level controls as well as compared with dyslexics with slow but accurate nonword decoding. Individual differences in the time course of multisensory spatial attention accounted for 31% of unique variance in the nonword reading performance of the entire dyslexic sample after controlling for age, IQ, and phonological skills. The present study suggests that multisensory “sluggish attention shifting”—related to a temporoparietal dysfunction—selectively impairs the sublexical mechanisms that are critical for reading development. These findings may offer a new approach for early identification and remediation of developmental dyslexia.


Author(s):  
Mai Geisen ◽  
Kyungwan Kim ◽  
Stefanie Klatt ◽  
Otmar Bock

AbstractSeveral studies have evaluated the distribution of visuo-spatial attention in a wayfinding task, using gaze direction as an indicator for the locus of attention. We extended that work by evaluating how visuo-spatial attention is modified by wayfinding practice. Young and older participants followed prescribed routes through a virtual city on six trials. Each trial was followed by a route recall test, where participants saw screenshots of intersections encountered, and had to indicate which way to proceed. Behavioral and gaze data were registered in those tests. Wayfinding accuracy increased from trial to trial, more so in young than in older persons. Total gaze time, mean fixation time, and the vertical scatter of fixations decreased from trial to trial, similarly in young and older persons. The horizontal scatter of fixations did not differ between trials and age groups. The incidence of fixations on the subsequently chosen side also did not differ between trials, but it increased in older age. We interpret these findings as evidence that as wayfinding practice increased, participants gradually narrowed their attentional focus to the most relevant screenshot area, processed information within this focus more efficiently, reduced the total time in which attention dwelled on the rejected side of the screenshot, but maintained the total time on the chosen side. These dynamic changes of visuo-spatial attention were comparable in young and older participants. However, it appears that decision-making differed between age groups: older persons’ attention dwelled longer on the chosen side before they made their choice.


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