scholarly journals A new motor synergy that serves the needs of oculomotor and eye lid systems while keeping the downtime of vision minimal

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Mohammad Farhan Khazali ◽  
Joern K Pomper ◽  
Aleksandra Smilgin ◽  
Friedemann Bunjes ◽  
Peter Thier
Keyword(s):  
Eye Movement ◽  
Visual Information ◽  
Visual Input ◽  
Visual Environment ◽  
Loss Of Information ◽  
New Type ◽  
The Subject ◽  
Motor Synergy ◽  
Eye Torsion ◽  
Visual Continuity

The purpose of blinks is to keep the eyes hydrated and to protect them. Blinks are rarely noticed by the subject as blink-induced alterations of visual input are blanked out without jeopardizing the perception of visual continuity, features blinks share with saccades. Although not perceived, the blink-induced disconnection from the visual environment leads to a loss of information. Therefore there is critical need to minimize it. Here we demonstrate evidence for a new type of eye movement serving a distinct oculomotor demand, namely the resetting of eye torsion, likewise inevitably causing a loss of visual information. By integrating this eye movement into blinks, the inevitable down times of vision associated with each of the two behaviors are synchronized and the overall downtime minimized.

Control and Sense of Eye Movement behind Closed Eyelids

Perception ◽  
1981 ◽  
Vol 10 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Jüri Allik ◽  
Marika Rauk ◽  
Aavo Luuk
Keyword(s):  
Eye Movement ◽  
Visual Information ◽  
Position Sense ◽  
Poor Control ◽  
Gaze Stabilization ◽  
Eyelid Closure ◽  
The Subject ◽  
Available Information ◽  
And Control ◽  
Human Eyes

To investigate the question of what happens with regard to position sense and control of the human eyes when the eyelids are closed, the contact-wire-free electromagnetic eye movement recording method was developed. It was shown that after the start of blinking or eyelid closure, the eyball moves up as the upper eyelids come down. Experimental data show human inability to maintain a given position of the eyes in the head under the closed eyelids. When the subject was asked to follow a simple geometrical path, a very weak metrical and topological correspondence between desired and actual paths occurred with closed eyes. It is proposed that the poor control of eye movements behind closed eyelids is due to the lack of available information about eye position in the head. The assumption was confirmed by providing artificial auditory feedback about eyeball position to the subject, which can be effectively used for gaze stabilization by the subject. It is suggested that visual information is the only useful basis for eye movement regulation under normal conditions.

The “Orienting Reflex” as an Input Indicator in “Subliminal” Perception

1972 ◽  
Vol 35 (1) ◽  
pp. 103-110
Author(s):  
Phillip Kleespies ◽  
Morton Wiener
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Exposure Duration ◽  
Visual Input ◽  
Orienting Reflex ◽  
Subliminal Perception ◽  
Thematic Content ◽  
Movement Data ◽  
Report Data ◽  
Input Indicator

This study explored (1) for evidence of visual input at so-called “subliminal” exposure durations, and (2) whether the response, if any, was a function of the thematic content of the stimulus. Thematic content (threatening versus non-threatening) and stimulus structure (angular versus curved) were varied independently under “subliminal,” “part-cue,” and “identification” exposure conditions. With Ss' reports and the frequency and latency of first eye movements (“orienting reflex”) as input indicators, there was no evidence of input differences which are a function of thematic content at any exposure duration, and the “report” data were consistent with the eye-movement data.

scholarly journals Visual Information Shapes the Dynamics of Corticobasal Ganglia Pathways during Response Selection and Inhibition

2015 ◽  
Vol 27 (7) ◽  
pp. 1344-1359 ◽  
Author(s):  
Sara Jahfari ◽  
Lourens Waldorp ◽  
K. Richard Ridderinkhof ◽  
H. Steven Scholte
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Response Selection ◽  
Selection Process ◽  
Effective Connectivity ◽  
Action Selection ◽  
Visual Input ◽  
Fmri Data ◽  
Response Strategies ◽  
Fast Flow

Action selection often requires the transformation of visual information into motor plans. Preventing premature responses may entail the suppression of visual input and/or of prepared muscle activity. This study examined how the quality of visual information affects frontobasal ganglia (BG) routes associated with response selection and inhibition. Human fMRI data were collected from a stop task with visually degraded or intact face stimuli. During go trials, degraded spatial frequency information reduced the speed of information accumulation and response cautiousness. Effective connectivity analysis of the fMRI data showed action selection to emerge through the classic direct and indirect BG pathways, with inputs deriving form both prefrontal and visual regions. When stimuli were degraded, visual and prefrontal regions processing the stimulus information increased connectivity strengths toward BG, whereas regions evaluating visual scene content or response strategies reduced connectivity toward BG. Response inhibition during stop trials recruited the indirect and hyperdirect BG pathways, with input from visual and prefrontal regions. Importantly, when stimuli were nondegraded and processed fast, the optimal stop model contained additional connections from prefrontal to visual cortex. Individual differences analysis revealed that stronger prefrontal-to-visual connectivity covaried with faster inhibition times. Therefore, prefrontal-to-visual cortex connections appear to suppress the fast flow of visual input for the go task, such that the inhibition process can finish before the selection process. These results indicate response selection and inhibition within the BG to emerge through the interplay of top–down adjustments from prefrontal and bottom–up input from sensory cortex.

Perceived self-motion in two visual contexts: Dissociable mechanisms underlie perception

2006 ◽  
Vol 16 (1-2) ◽  
pp. 23-28 ◽  
Author(s):  
W. Geoffrey Wright ◽  
Paul DiZio ◽  
James R. Lackner
Keyword(s):  
Motion Perception ◽  
Path Integration ◽  
Visual Input ◽  
Visual Scene ◽  
Spatial Context ◽  
Immersive Virtual Environment ◽  
Physical Context ◽  
The Subject ◽  
Self Motion ◽  
Visual Acceleration

We evaluated the influence of moving visual scenes and knowledge of spatial and physical context on visually induced self-motion perception in an immersive virtual environment. A sinusoidal, vertically oscillating visual stimulus induced perceptions of self-motion that matched changes in visual acceleration. Subjects reported peaks of perceived self-motion in synchrony with peaks of visual acceleration and opposite in direction to visual scene motion. Spatial context was manipulated by testing subjects in the environment that matched the room in the visual scene or by testing them in a separate chamber. Physical context was manipulated by testing the subject while seated in a stable, earth-fixed desk chair or in an apparatus capable of large linear motions, however, in both conditions no actual motion occurred. The compellingness of perceived self-motion was increased significantly when the spatial context matched the visual input and actual body displacement was possible, however, the latency and amplitude of perceived self-motion were unaffected by the spatial or physical context. We propose that two dissociable processes are involved in self-motion perception: one process, primarily driven by visual input, affects vection latency and path integration, the other process, receiving cognitive input, drives the compellingness of perceived self-motion.

The Organization of Life before Death in Two Québec Cultural Configurations

1993 ◽  
Vol 27 (1) ◽  
pp. 35-50
Author(s):  
Luce Des Aulniers
Keyword(s):  
Basic Concept ◽  
Data Gathering ◽  
Doctoral Thesis ◽  
Historical Factors ◽  
Personal Experiences ◽  
Life Threatening ◽  
New Type ◽  
The Subject ◽  
Fatal Illness ◽  
Data Gathering And Analysis

This article is based on data from a doctoral thesis about the “anthropology of life-threatening, death and time.” [1] The interpretation is made from twelve life reviews set at homes of people who suffered a serious, but not necessarily fatal illness. Two-cultural configurations are chosen along the axis of rural-urban polarity. It focuses on three types of solidarity, facing the awareness of death: 1) the ethnographic position, in data gathering and analysis. Specific propositions are given concerning the subject and intersubjectivity, cultural generalization of personal experiences, and scientific criteria; 2) what helps cope with illness. Pre-death practices are structured on the basic concept of resistance to illness and preparation for death practices rely on a coherence “test.” The genealogy of practices emerge in six situational and seven historical factors; 3) the conditions of a new type of rite before death and its functions, beside the institutionalization of illness and death.

scholarly journals Refixation control in free viewing: a specialized mechanism divulged by eye-movement-related brain activity

2018 ◽  
Vol 120 (5) ◽  
pp. 2311-2324 ◽  
Author(s):  
Andrey R. Nikolaev ◽  
Radha Nila Meghanathan ◽  
Cees van Leeuwen
Keyword(s):  
Eye Movement ◽  
Visual Information ◽  
Direct Evidence ◽  
Search Task ◽  
Visual Search Task ◽  
Brain Activity ◽  
Movement Control ◽  
Planning Stage ◽  
Eye Fixations ◽  
Free Viewing

In free viewing, the eyes return to previously visited locations rather frequently, even though the attentional and memory-related processes controlling eye-movement show a strong antirefixation bias. To overcome this bias, a special refixation triggering mechanism may have to be recruited. We probed the neural evidence for such a mechanism by combining eye tracking with EEG recording. A distinctive signal associated with refixation planning was observed in the EEG during the presaccadic interval: the presaccadic potential was reduced in amplitude before a refixation compared with normal fixations. The result offers direct evidence for a special refixation mechanism that operates in the saccade planning stage of eye movement control. Once the eyes have landed on the revisited location, acquisition of visual information proceeds indistinguishably from ordinary fixations. NEW & NOTEWORTHY A substantial proportion of eye fixations in human natural viewing behavior are revisits of recently visited locations, i.e., refixations. Our recently developed methods enabled us to study refixations in a free viewing visual search task, using combined eye movement and EEG recording. We identified in the EEG a distinctive refixation-related signal, signifying a control mechanism specific to refixations as opposed to ordinary eye fixations.

scholarly journals EXPERIMENTAL ONLINE CASE STUDY FOR A BREAKTHROUGH IN STUDENT ENGAGEMENT: FOCUS GROUP RESULTS

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
James Theroux ◽  
Cari Carpenter ◽  
Clare Kilbane
Keyword(s):  
Student Engagement ◽  
Focus Group ◽  
Real Time ◽  
Group Discussion ◽  
Full Time ◽  
The Real ◽  
Building Process ◽  
New Type ◽  
The Subject

A new type of case study, called the real-time case (RTC), was produced in the fall of 2001 and distributed via the Internet to business classes at four universities in the US and Canada. The real-time case presented the story of one company's growth and development throughout a 14-week semester. A case writer stationed full-time at the subject company published case installments weekly on the Web, allowing students to view the company-building process as it happened. The 14-week coverage of RTC enabled students to study the subject company in unprecedented depth and detail. RTC's real-time interactivity allowed students to share their analyses and best thinking with the company leadership during the company’s decision-making process.A major objective in producing the case was to heighten student engagement with the case material. To evaluate whether this objective was achieved, a survey and a focus group discussion were conducted with one of the participating MBA classes. Results from the survey and the focus group showed a high degree of engagement, plus many other benefits from the new type of case study.

scholarly journals Conscious and unconscious memory differentially impact attention: Eye movements, visual search, and recognition processes

2019 ◽  
Author(s):  
Michelle Ramey ◽  
Andrew P. Yonelinas ◽  
John M. Henderson
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
Eye Movement ◽  
Visual Information ◽  
Subjective Memory ◽  
Conscious Recollection ◽  
Memory Awareness ◽  
Efficient Extraction ◽  
Subjective Reports ◽  
Unconscious Memory

A hotly debated question is whether memory influences attention through conscious or unconscious processes. To address this controversy, we measured eye movements while participants searched repeated real-world scenes for embedded targets, and we assessed memory for each scene using confidence-based methods to isolate different states of subjective memory awareness. We found that memory-informed eye movements during visual search were predicted both by conscious recollection, which led to a highly precise first eye movement toward the remembered location, and by unconscious memory, which increased search efficiency by gradually directing the eyes toward the target throughout the search trial. In contrast, these eye movement measures were not influenced by familiarity-based memory (i.e., changes in subjective reports of memory strength). The results indicate that conscious recollection and unconscious memory can each play distinct and complementary roles in guiding attention to facilitate efficient extraction of visual information.

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