Are hemianopic reading and visual exploration impairments visually elicited? New insights from eye movements in simulated hemianopia

2009 ◽  
Vol 47 (3) ◽  
pp. 733-746 ◽  
Author(s):  
Susanne Schuett ◽  
Robert W. Kentridge ◽  
Josef Zihl ◽  
Charles A. Heywood
PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245777
Author(s):  
Fanny Poncet ◽  
Robert Soussignan ◽  
Margaux Jaffiol ◽  
Baptiste Gaudelus ◽  
Arnaud Leleu ◽  
...  

Recognizing facial expressions of emotions is a fundamental ability for adaptation to the social environment. To date, it remains unclear whether the spatial distribution of eye movements predicts accurate recognition or, on the contrary, confusion in the recognition of facial emotions. In the present study, we asked participants to recognize facial emotions while monitoring their gaze behavior using eye-tracking technology. In Experiment 1a, 40 participants (20 women) performed a classic facial emotion recognition task with a 5-choice procedure (anger, disgust, fear, happiness, sadness). In Experiment 1b, a second group of 40 participants (20 women) was exposed to the same materials and procedure except that they were instructed to say whether (i.e., Yes/No response) the face expressed a specific emotion (e.g., anger), with the five emotion categories tested in distinct blocks. In Experiment 2, two groups of 32 participants performed the same task as in Experiment 1a while exposed to partial facial expressions composed of actions units (AUs) present or absent in some parts of the face (top, middle, or bottom). The coding of the AUs produced by the models showed complex facial configurations for most emotional expressions, with several AUs in common. Eye-tracking data indicated that relevant facial actions were actively gazed at by the decoders during both accurate recognition and errors. False recognition was mainly associated with the additional visual exploration of less relevant facial actions in regions containing ambiguous AUs or AUs relevant to other emotional expressions. Finally, the recognition of facial emotions from partial expressions showed that no single facial actions were necessary to effectively communicate an emotional state. In contrast, the recognition of facial emotions relied on the integration of a complex set of facial cues.


2021 ◽  
Author(s):  
Naghmeh Mostofi ◽  
Janis Intoy ◽  
Michele Rucci

AbstractHumans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primate’s social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the peri-saccadic time-course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed new light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades.


2014 ◽  
Vol 7 (4) ◽  
Author(s):  
Sophie Lemonnier ◽  
Roland Brémond ◽  
Thierry Baccino

An experiment was conducted in a driving simulator to test how eye-movements patterns evolve over time according to the decision-making processes involved in a driving task. Participants had to drive up to crossroads and decide to stop or not. The decision-making task was considered as the succession of two phases associated with cognitive processes: Differentiation (leading to a prior decision) and Consolidation (leading to a final decision). Road signs (Stop, Priority and GiveWay) varied across situations, and the stopping behavior (Go and NoGo) was recorded. Saccade amplitudes and fixation durations were analyzed. Specific patterns were found for each condition in accordance with the associated processes: high visual exploration (larger saccade amplitudes and shorter fixation durations) for the Differentiation phase, and lower visual exploration (smaller saccades and longer fixations) for the Consolidation phase. These results support that eye-movements can provide good indexes of underlying processes occurring during a decision-making task in an everyday context.


2020 ◽  
Author(s):  
R. Shayna Rosenbaum ◽  
Julia G. Halilova ◽  
Sabrina Agnihotri ◽  
Maria C. D'Angelo ◽  
Gordon Winocur ◽  
...  

How well do we know our city? It turns out, much more poorly than we might imagine. We used declarative memory and eye-tracking techniques to examine people’s ability to detect modifications of landmarks in Toronto locales with which they have had extensive experience. Participants were poor at identifying which scenes contained altered landmarks, whether the modification was to the landmarks’ relative size, internal features, or surrounding context. To determine whether an indirect measure would prove more sensitive, we tracked eye movements during viewing. Changes in overall visual exploration, but not to specific regions of change, were related to participants’ explicit endorsement of scenes as modified. These results support the contention that very familiar landmarks are strongly integrated within the spatial context in which they were first experienced, so that any changes that are consciously detected are at a global or coarse, but not local or fine-grained, level.


2010 ◽  
Vol 59 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Katerina Lukasova ◽  
Lívia Lemos Zanin ◽  
Marcel Valois Chucre ◽  
Gamaliel Coutinho de Macedo ◽  
Elizeu Coutinho de Macedo

OBJECTIVE: Compare pattern of exploratory eye movements during visual scanning of the Rorschach and TAT test cards in people with schizophrenia and controls. METHOD: 10 participants with schizophrenia and 10 controls matched by age, schooling and intellectual level participated in the study. Severity of symptoms was evaluated with the Positive and Negative Syndrome Scale. Test cards were divided into three groups: TAT cards with scenes content, TAT cards with interaction content (TAT-faces), and Rorschach cards with abstract images. Eye movements were analyzed for: total number, duration and location of fixation; and length of saccadic movements. RESULTS: Different pattern of eye movement was found, with schizophrenia participants showing lower number of fixations but longer fixation duration in Rorschach cards and TAT-faces. The biggest difference was observed in Rorschach, followed by TAT-faces and TAT-scene cards. CONCLUSIONS: Results suggest alteration in visual exploration mechanisms possibly related to integration of abstract visual information.


Author(s):  
Matteo Sozzi ◽  
Michela Balconi ◽  
Luigi Pisani ◽  
Claudio Mariani

Aim of this study is to explore behavioral responses and eye movements of unilateral neglect patients in a virtual bisection task. Space to be bisected was included between two endpoint, segment length together with segment spatial dislocation were varied in order to test the presence of a gradient effect in both bisection behavior and visual exploration. Ten right neglect patients took part to the study, all data were then matched with those obtained from ten healthy participants. Behavioral measures (bisection and RTs) and eye-movements (fixation count and duration; first fixation count) were analyzed. Consistent spatial biases were found for bisection responses, RTs, fixation count and duration, as well as for the first fixation count. We then find a significant rightward bias in patients, i.e. increasing rightside bisection and rightward fixations when the stimuli were in the extreme left-position. Concerning merely segment length, we observed significant differences between-groups only for eye movement behavior, with increased rightward fixation count and duration in response to longer segments. In conclusion, left-to-right and longer-to-shorter continuous-gradient effects were not totally supported by our results, whereas an extreme-left gradient effect was suggested and discussed.


2009 ◽  
Vol 47 (7) ◽  
pp. 1712-1720 ◽  
Author(s):  
Susanne Schuett ◽  
Robert W. Kentridge ◽  
Josef Zihl ◽  
Charles A. Heywood

2019 ◽  
Author(s):  
James E. Kragel ◽  
Stephen VanHaerents ◽  
Jessica W. Templer ◽  
Stephan Schuele ◽  
Joshua M. Rosenow ◽  
...  

SummaryThe hippocampus supports memory encoding and retrieval, with distinct phases of theta oscillations modulating the amplitude of gamma-band activity during each process. Encoding and retrieval operations dynamically interact over rapid timescales, especially when sensory information conflicts with memory. The ability to link hippocampal dynamics to specific memory-guided behaviors has been limited by experiments that lack the temporal resolution to segregate when encoding and retrieval occur. To resolve this issue, we simultaneously tracked eye movements and hippocampal field potentials while neurosurgical patients performed a spatial memory task. Novelty-driven fixations increased phase-locking to the theta rhythm, which predicted successful memory performance. Theta to gamma phase amplitude coupling increased during these viewing behaviors and predicted forgetting of conflicting memories. In contrast, theta phase-locking preceded fixations initiated by memory retrieval, indicating that the hippocampus coordinates memory-guided eye movements. These findings suggest that theta oscillations in the hippocampus support learning through two interleaved processes: strengthening the encoding of novel information and guiding exploration based on prior experience.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
James E Kragel ◽  
Stephen VanHaerents ◽  
Jessica W Templer ◽  
Stephan Schuele ◽  
Joshua M Rosenow ◽  
...  

The hippocampus supports memory encoding and retrieval, which may occur at distinct phases of the theta cycle. These processes dynamically interact over rapid timescales, especially when sensory information conflicts with memory. The ability to link hippocampal dynamics to memory-guided behaviors has been limited by experiments that lack the temporal resolution to segregate encoding and retrieval. Here, we simultaneously tracked eye movements and hippocampal field potentials while neurosurgical patients performed a spatial memory task. Phase-locking at the peak of theta preceded fixations to retrieved locations, indicating that the hippocampus coordinates memory-guided eye movements. In contrast, phase-locking at the trough of theta followed fixations to novel object-locations and predicted intact memory of the original location. Theta-gamma phase amplitude coupling increased during fixations to conflicting visual content, but predicted memory updating. Hippocampal theta thus supports learning through two interleaved processes: strengthening encoding of novel information and guiding exploration based on prior experience.


Author(s):  
Marcin Leszczynski ◽  
Tobias Staudigl ◽  
Leila Chaieb ◽  
Simon Jonas Enkirch ◽  
Juergen Fell ◽  
...  

AbstractHumans and other primates explore visual scenes by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using rare recordings in the human thalamus of three surgical patients, we found saccade-related phase concentration, peaking at 3-4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80-180 Hz). Our results provide evidence for saccade-related modulation of neuronal excitability dynamics in the ANT, consistent with the idea that these nuclei are engaged during visual active sensing. These findings show that during real-world active visual exploration neural dynamics in the human ANT, a part of extended hippocampal–diencephalic system for episodic memory, exhibit modulations that might be underestimated in typical passive viewing.


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