scholarly journals Visual encoding and fixation target selection in free viewing: presaccadic brain potentials

2013 ◽  
Vol 7 ◽  
Author(s):  
Andrey R. Nikolaev ◽  
Peter Jurica ◽  
Chie Nakatani ◽  
Gijs Plomp ◽  
Cees van Leeuwen
Keyword(s):  
Target Selection ◽  
Fixation Target ◽  
Brain Potentials ◽  
Free Viewing ◽  
Visual Encoding

scholarly journals Spatially guided distractor suppression during visual search

2020 ◽  
Author(s):  
Tobias Feldmann-Wüstefeld ◽  
Marina Weinberger ◽  
Edward Awh
Keyword(s):  
Multivariate Analyses ◽  
Target Selection ◽  
Basic Question ◽  
Spatial Gradient ◽  
Selection Effects ◽  
Theta Band ◽  
Neural Signals ◽  
Past Work ◽  
Visual Encoding ◽  
Selection Of

AbstractPast work has demonstrated that active suppression of salient distractors is a critical part of visual selection. Evidence for goal-driven suppression includes below-baseline visual encoding at the position of salient distractors (Gaspelin and Luck, 2015) and neural signals such as the Pd that track the position and number of distractors in the visual field (Feldmann-Wustefeld and Vogel, 2019). One basic question regarding distractor suppression is whether it is inherently spatial or nonspatial in character. Indeed, past work has shown that distractors evoke both spatial (Theeuwes, 1992) and nonspatial forms of interference (Folk and Remington, 1998), motivating a direct examination of whether space is integral to goal-driven distractor suppression. Here, we provide clear evidence for a spatial gradient of suppression surrounding salient singleton distractors. Replicating past work, both reaction time and neural indices of target selection improved monotonically as the distance between target and distractor increased. Importantly, these target selection effects were paralleled by a monotonic decline in the amplitude of the Pd, an electrophysiological index of distractor suppression. Moreover, multivariate analyses revealed spatially selective activity in the theta band that tracked the position of the target and – critically – revealed suppressed activity at spatial channels centered on distractor positions. Thus, goal-driven selection of relevant over irrelevant information benefits from a spatial gradient of suppression surrounding salient distractors.

scholarly journals Enhanced representation of space by prefrontal neuronal ensembles and its dependence on cognitive states

2016 ◽  
Author(s):  
Mohammad-Reza A. Dehaqani ◽  
Abdol-Hossein Vahabie ◽  
Mohammadbagher Parsa ◽  
Behard Noudoost ◽  
Alireza Soltani
Keyword(s):  
Cognitive Flexibility ◽  
Target Selection ◽  
Visual Space ◽  
Neural Representation ◽  
Noise Correlation ◽  
Neuronal Ensembles ◽  
Cognitive States ◽  
Visual Encoding ◽  
Representation Of Space ◽  
Spatial Locations

AbstractAlthough individual neurons can be highly selective to particular stimuli and certain upcoming actions, they can provide a complex representation of stimuli and actions at the level of population. The ability to dynamically allocate neural resources is crucial for cognitive flexibility. However, it is unclear whether cognitive flexibility emerges from changes in activity at the level of individual neurons, population, or both. By applying a combination of decoding and encoding methods to simultaneously recorded neural data, we show that while maintaining their stimulus selectivity, neurons in prefrontal cortex alter their correlated activity during various cognitive states, resulting in an enhanced representation of visual space. During a task with various cognitive states, individual prefrontal neurons maintained their limited spatial sensitivity between visual encoding and saccadic target selection whereas the population selectively improved its encoding of spatial locations far from the neurons' preferred locations. This 'encoding expansion' relied on high-dimensional neural representations and was accompanied by selective reductions in noise correlation for non-preferred locations. Our results demonstrate that through recruitment of less-informative neurons and reductions of noise correlation in their activity, the representation of space by neuronal ensembles can be dynamically enhanced, and suggest that cognitive flexibility is mainly achieved by changes in neural representation at the level of population of prefrontal neurons rather than individual neurons.

scholarly journals Evidence for a Structural Analysis of Target Selection in Picture Viewing

2011 ◽  
Vol 4 (1) ◽  
Author(s):  
Christoph Rasche ◽  
Benjamin W. Tatler
Keyword(s):  
Structural Analysis ◽  
Real World ◽  
Target Selection ◽  
Fixation Location ◽  
Free Viewing ◽  
Fixation Locations ◽  
Two Measures ◽  
Picture Viewing ◽  
Saccadic Target

Spontaneous fixations onto shapes are driven by a structural analysis. But is such analysis also carried out during free viewing of real-world scenes? Here, we analyze how fixation locations in such scenes are related to their region using the region's symmetric axes as a reference. Each fixation location is compared with respect to its nearest symmetric-axis segment by a latitude and a longitude measure. Analyzing the distributions for the two measures we find that there exist fixation biases for L features and parallel contours, suggesting that structural analysis may play a role in saccadic target selection during free viewing.

scholarly journals Saccadic target selection and temporal properties of visual encoding

2010 ◽  
Vol 10 (7) ◽  
pp. 499-499
Author(s):  
J. P. de Vries ◽  
I. T. C. Hooge ◽  
M. A. Wiering ◽  
F. A. J. Verstraten
Keyword(s):  
Target Selection ◽  
Temporal Properties ◽  
Visual Encoding ◽  
Saccadic Target

Skipping Breakfast Affects the Early Steps of Cognitive Processing

2019 ◽  
Vol 33 (2) ◽  
pp. 109-118
Author(s):  
Andrés Antonio González-Garrido ◽  
Jacobo José Brofman-Epelbaum ◽  
Fabiola Reveca Gómez-Velázquez ◽  
Sebastián Agustín Balart-Sánchez ◽  
Julieta Ramos-Loyo
Keyword(s):  
Working Memory ◽  
Cognitive Processing ◽  
Task Difficulty ◽  
Brain Activity ◽  
Reaction Times ◽  
Brain Potentials ◽  
Brain Functioning ◽  
Attentional Processes ◽  
Electrical Brain Activity ◽  
Skipping Breakfast

Abstract. It has been generally accepted that skipping breakfast adversely affects cognition, mainly disturbing the attentional processes. However, the effects of short-term fasting upon brain functioning are still unclear. We aimed to evaluate the effect of skipping breakfast on cognitive processing by studying the electrical brain activity of young healthy individuals while performing several working memory tasks. Accordingly, the behavioral results and event-related brain potentials (ERPs) of 20 healthy university students (10 males) were obtained and compared through analysis of variances (ANOVAs), during the performance of three n-back working memory (WM) tasks in two morning sessions on both normal (after breakfast) and 12-hour fasting conditions. Significantly fewer correct responses were achieved during fasting, mainly affecting the higher WM load task. In addition, there were prolonged reaction times with increased task difficulty, regardless of breakfast intake. ERP showed a significant voltage decrement for N200 and P300 during fasting, while the amplitude of P200 notably increased. The results suggest skipping breakfast disturbs earlier cognitive processing steps, particularly attention allocation, early decoding in working memory, and stimulus evaluation, and this effect increases with task difficulty.

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