Hand-eye coordination during sequential tasks

1992 ◽  
Vol 337 (1281) ◽  
pp. 331-339 ◽  
Keyword(s):  
Target Location ◽  
Terminal Phase ◽  
Cognitive Mechanisms ◽  
The Gaze ◽  
Eye Fixations ◽  
Task Requirements ◽  
Before And After ◽  
Hand Eye Coordination ◽  
Main Observation ◽  
The Subject

The small angle subtended by the hum an fovea places a premium on the ability to quickly and accurately direct the gaze to targets of interest. Thus the resultant saccadic eye fixations are a very instructive behaviour, revealing much about the underlying cognitive mechanisms that guide them. Of particular interest are the eye fixations used in hand-eye coordination. Such coordination has been extensively studied for single movements from a source location to a target location. In contrast, we have studied multiple fixations where the sources and targets are a function of a task and chosen dynamically by the subject according to task requirements. T he task chosen is a copying task: subjects must copy a figure made up of contiguous coloured blocks as fast as possible. The main observation is that although eye fixations are used for the terminal phase of hand movements, they are used for other tasks before and after that phase. The analysis of the spatial and temporal details of these fixations suggests that the underlying decision process that moves the eyes leaves key decisions until just before they are required.

Gaze control during reaching is flexibly modulated to optimize task outcome

2021 ◽  
Author(s):  
Naotoshi Abekawa ◽  
Hiroaki Gomi ◽  
Jörn Diedrichsen
Keyword(s):  
Motor Coordination ◽  
Target Location ◽  
Task Demands ◽  
Gaze Control ◽  
The Gaze ◽  
Task Requirements ◽  
Current Task ◽  
Gaze Anchoring ◽  
Adaptive Solution ◽  
Reward Contingencies

When reaching for an object with the hand, the gaze is usually directed at the target. In a laboratory setting, fixation is strongly maintained at the reach target until the reaching is completed, a phenomenon known as "gaze-anchoring". While conventional accounts of such tight eye-hand coordination have often emphasized the internal synergetic linkage between both motor systems, more recent optimal control theories regard motor coordination as the adaptive solution to task requirements. We here investigated to what degree gaze control during reaching is modulated by task demands. We adopted a gaze-anchoring paradigm in which participants had to reach for a target location. During the reach, they additionally had to make a saccadic eye movement to a salient visual cue presented at locations other than the target. We manipulated the task demands by independently changing reward contingencies for saccade reaction time (RT) and reaching accuracy. On average, both saccade RTs and reach error varied systematically with reward condition, with reach accuracy improving when the saccade was delayed. The distribution of the saccade RTs showed two types of eye movements: fast saccades with short RTs, and voluntary saccade with longer RTs. Increased reward for high reach accuracy reduced the probability of reflexive fast saccades, but left their latency unchanged. The results suggest that gaze-anchoring acts through a suppression of fast saccades, a mechanism that can be adaptively adjusted to the current task demands.

Perisaccadic Mislocalization of Visual Targets by Head-Free Gaze Shifts: Visual or Motor?

2008 ◽  
Vol 100 (4) ◽  
pp. 1848-1867 ◽  
Author(s):  
Sigrid M. C. I. van Wetter ◽  
A. John van Opstal
Keyword(s):  
Target Location ◽  
Saccadic Eye Movements ◽  
Open Loop ◽  
Spatial Updating ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
The Gaze ◽  
Visual Probe ◽  
Saccade Onset ◽  
Saccade Direction

Such perisaccadic mislocalization is maximal in the direction of the saccade and varies systematically with the target-saccade onset delay. We have recently shown that under head-fixed conditions perisaccadic errors do not follow the quantitative predictions of current visuomotor models that explain these mislocalizations in terms of spatial updating. These models all assume sluggish eye-movement feedback and therefore predict that errors should vary systematically with the amplitude and kinematics of the intervening saccade. Instead, we reported that errors depend only weakly on the saccade amplitude. An alternative explanation for the data is that around the saccade the perceived target location undergoes a uniform transient shift in the saccade direction, but that the oculomotor feedback is, on average, accurate. This “ visual shift” hypothesis predicts that errors will also remain insensitive to kinematic variability within much larger head-free gaze shifts. Here we test this prediction by presenting a brief visual probe near the onset of gaze saccades between 40 and 70° amplitude. According to models with inaccurate gaze-motor feedback, the expected perisaccadic errors for such gaze shifts should be as large as 30° and depend heavily on the kinematics of the gaze shift. In contrast, we found that the actual peak errors were similar to those reported for much smaller saccadic eye movements, i.e., on average about 10°, and that neither gaze-shift amplitude nor kinematics plays a systematic role. Our data further corroborate the visual origin of perisaccadic mislocalization under open-loop conditions and strengthen the idea that efferent feedback signals in the gaze-control system are fast and accurate.

Efferent vagal innervation of canine ventricle

1985 ◽  
Vol 248 (1) ◽  
pp. H89-H97 ◽  
Author(s):  
N. Takahashi ◽  
M. J. Barber ◽  
D. P. Zipes
Keyword(s):  
Coronary Artery ◽  
Vagal Stimulation ◽  
Left Ventricular ◽  
Constant Infusion ◽  
Epicardial Surface ◽  
Before And After ◽  
Vagal Innervation ◽  
The Subject ◽  
Infusion Of Norepinephrine ◽  
The Right

The route efferent vagal fibers travel to reach the left ventricle is not clear and was the subject of this investigation. We measured left ventricular and septal effective refractory period (ERP) changes during vagal stimulation and a constant infusion of norepinephrine, before and after phenol was applied at selected sites of the heart to interrupt efferent vagal fibers that may be traveling in that area. Phenol applied to the atrioventricular (AV) groove between the origin of the right coronary artery anteriorly to the posterior descending branch of the circumflex coronary artery completely eliminated vagal-induced prolongation of ERP in the anterior and posterior left ventricular free wall and reduced, but did not eliminate, ERP prolongation in the septum. A large (3-cm radius) epicardial circle of phenol prevented vagal-induced ERP prolongation within the circle in all dogs, while a small (1-cm radius) epicardial circle of phenol failed to prevent vagal-induced ERP changes within the circle in any dog. An intermediate (2-cm radius) circle eliminated vagal effects on ERP in 13 of 18 dogs. Arcs of phenol, to duplicate the upper portion of the circle, applied sequentially from apex to base eliminated efferent vagal effects only when painted near or at the AV groove. We conclude that the majority of efferent vagal fibers enroute to innervate the anterior and posterior left ventricular epicardium cross the AV groove within 0.25-0.5 mm (depth of phenol destruction) of the epicardial surface.(ABSTRACT TRUNCATED AT 250 WORDS)

The Israeli–Lebanese war of 2006: consequences for Lebanon

2008 ◽  
Vol 1 (2) ◽  
pp. 187-210
Author(s):  
Ziad Hafez
Keyword(s):  
Arab Countries ◽  
The Political ◽  
National Unity ◽  
Major Consequence ◽  
Political Narrative ◽  
Defence Policy ◽  
Before And After ◽  
The Usa ◽  
The Subject ◽  
The Impact

This article focuses on the political narrative in Lebanon before and after the Israeli war against Lebanon in 2006. It revolves around the subject of national unity as a sine qua non condition for success for the Lebanese resistance led by Hezbollah. A major consequence of the narrative on national unity is the need to build a modern state and establish a cohesive defence policy. The paper also examines the impact of the war on Lebanon's economy and on its relations with the rest of the world (the USA, France, Syria, Arab countries, and Iran).

Improving Student Creativity Activeness And Implementation Approach In Cbsa On Civics Lesson Grade Ii Sd Negeri 39 Lengayang Gompong.Kec Markets Academic Year 2016/2017

2018 ◽  
Vol 1 (2) ◽  
pp. 89-96
Author(s):  
Darleli Darleli
Keyword(s):  
Civic Education ◽  
Evaluation Study ◽  
Class Action ◽  
Peer Tutors ◽  
Implementation Approach ◽  
Before And After ◽  
Study Population ◽  
Grade Ii ◽  
The Subject ◽  
Academic Year

    The purpose of this study is to prove that the use of the environment around the school can improve students' understanding of the subject Civic Education in Elementary School student 39 Class II Gompong Market. This study uses a class action approach. The study population was taken of all students in grade II , the data collection techniques used artificial teacher learning achievement test. Actions performed a total of two cycles. Data analysis techniques used analysis of the percentage of change in the results of the evaluation study before and after tutoring services with peer tutors. Thus there is an increase in students' mastery of the first cycle and the second cycle. Based on the above, it can be made a conclusion as follows: " Improving Student Creativity activeness And Implementation Approach In CBSA On Civics Lesson Grade II SD Negeri 39 Lengayang Gompong.Kec Markets Academic Year 2016/2017 " .    

scholarly journals Saccades and smooth pursuit eye movements trigger equivalent gaze-cued orienting effects

2018 ◽  
Vol 71 (9) ◽  
pp. 1860-1872 ◽  
Author(s):  
Stephen RH Langton ◽  
Alex H McIntyre ◽  
Peter JB Hancock ◽  
Helmut Leder
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Location ◽  
Eye Gaze ◽  
Saccadic Eye Movements ◽  
Gaze Shift ◽  
The Gaze ◽  
Orienting Effect ◽  
Motion Speed ◽  
Uncued Target

Research has established that a perceived eye gaze produces a concomitant shift in a viewer’s spatial attention in the direction of that gaze. The two experiments reported here investigate the extent to which the nature of the eye movement made by the gazer contributes to this orienting effect. On each trial in these experiments, participants were asked to make a speeded response to a target that could appear in a location toward which a centrally presented face had just gazed (a cued target) or in a location that was not the recipient of a gaze (an uncued target). The gaze cues consisted of either fast saccadic eye movements or slower smooth pursuit movements. Cued targets were responded to faster than uncued targets, and this gaze-cued orienting effect was found to be equivalent for each type of gaze shift both when the gazes were un-predictive of target location (Experiment 1) and counterpredictive of target location (Experiment 2). The results offer no support for the hypothesis that motion speed modulates gaze-cued orienting. However, they do suggest that motion of the eyes per se, regardless of the type of movement, may be sufficient to trigger an orienting effect.

scholarly journals Avaliação Social Construtivista de uma Experiência em EAD: o uso do COLLES enquanto instrumento de coleta de dados

EAD em FOCO ◽  
2016 ◽  
Vol 6 (2) ◽  
Author(s):  
Fernanda Roda Cassundé ◽  
Edson Gomes Silva ◽  
Laís da Silva Santos ◽  
Adler Henrique Santos Souza ◽  
Graça Suely Gomes Souza ◽  
...  
Keyword(s):  
Distance Education ◽  
Learning Environment ◽  
Public Management ◽  
Self Assessment ◽  
Before And After ◽  
Postgraduate Studies ◽  
On Line ◽  
The Subject ◽  
On Line Learning ◽  
Assessment Questionnaire

O presente trabalho tem como objetivo avaliar as expectativas e experiências dos estudantes em relação à disciplina O Estado e os problemas contemporâneos, do Curso de Especialização em Gestão Pública da Universidade Federal do Vale do São Francisco (Univasf). Para isso, foi realizada a aplicação do questionário de autoavaliação Colles (Constructivist Online Learning Environment Survey) verificando-se as possíveis mudanças na percepção e comparando-se os resultados do antes e do depois referente a seis dimensões: relevância, reflexão, interação, apoio dos tutores, apoio dos colegas e compreensão. Participaram da pesquisa 97 alunos, em dois momentos diferentes: no início das aulas, para conhecer as expectativas dos estudantes e no final delas, para se ter uma compreensão da realidade vivenciada. Os resultados revelaram que a análise da experiência sempre foi inferior quando comparada à análise da expectativa em todos os aspectos apresentados, evidenciando que alguns participantes sentenciaram não ter alcançado os objetivos pretendidos.Palavras-chave: Colles, Educação a distância, Avaliação, Pós-graduação, PNAP.  Social Constructivist Evaluation of an Experience in Distance Education: the use of Colles as Data Collection InstrumentAbstract This study aims to evaluate the students expectations and experiences regarding the subject "The State and the contemporary problems", in Public Management post-graduation from the Federal University of São Francisco Valley (UNIVASF). For this, the application carried out the self-assessment questionnaire COLLES (Constructivist On-line Learning Environment Survey) checking for possible changes in perception and comparing the results before and after referring to the six dimensions: relevance, reflection, interaction, support tutors, peer support and understanding. The participants were 97 students in two different times at the beginning of classes, to meet the expectations of students and at the end of these, to have an understanding of experienced reality. The results showed that the students' experience overcame the negative assessment in all aspects presented, showing that some participants sentenced not have achieved the intended objectives.Keywords: COLLES, Distance education, Evaluation, Postgraduate studies, PNAP. 

scholarly journals Jesse Shera, The Wars and The Pietá

2017 ◽  
Vol 11 (2) ◽  
Author(s):  
Rodrigo Porto Bozzetti ◽  
Gustavo Saldanha
Keyword(s):  
World War Ii ◽  
Social Epistemology ◽  
Information Science ◽  
World War ◽  
Social Approach ◽  
Theoretical Formulation ◽  
Social Nature ◽  
The Future ◽  
Before And After ◽  
The Subject

The purpose of this paper, considering the relevance of Shera thoughts and its repercussions, is to reposition, in epistemological-historical terms, Jesse Shera’s approaches and their impacts according to a relation between life and work of the epistemologist. Without the intention of an exhaustive discussion, the purpose is to understand some unequivocal relations between the Shera critique for the context of its theoretical formulation and the consequences of this approach contrary to some tendencies originating from the technical and bureaucratic roots of the field (before and after World War II). It is deduced that Shera, rather than observing the sociopolitical reality and technical partner in which the texture of alibrary-based thought (but visualized by him as documentaryinformational), establishes, in his own praxis, social epistemology as a sort of "critique of the future," that is, as a praxis of the reflexive activity of the subject inserted in this episteme. In our discussion, the epistemological-social approach represents a vanguard for the context of its affirmation, a reassessment for the immediate decades to its presentation(years 1960 and 1970) and a critique for the future of what was consolidated under the notion of information Science, anticipating affirmations of "social nature" of the 1980s and 1990s in the field of information.

scholarly journals Pengembangan bahan ajar berbasis muatan lokal pada mata kuliah Pendidikan Kewarganegaraan

2016 ◽  
Vol 13 (2) ◽  
pp. 113-126
Author(s):  
Emil El Faisal ◽  
Sulkipani Sulkipani
Keyword(s):  
Student Achievement ◽  
Civic Education ◽  
Field Evaluation ◽  
Pilot Project ◽  
Local Content ◽  
Before And After ◽  
The Subject ◽  
The Mean ◽  
Potential Impact ◽  
History Department

This research aimed at (1) developing teaching materials based on local content for Civic Education in University; and (2) describing the potential impact of local content on student consciousness on local culture. It was a developmental research. The subject were student registered in Civic Education Course (Mata Kuliah PKn) at History Department. Pilot project was validated through one to one, small group, and field evaluation. The analyzed result indicates that the developed instrument was valid and has potential impact. Supported data shows that the mean score prior to implementation was 6.86 and after implementation was 7.73. In other words, there was an increasing student achievement before and after its implementation. Accordingly, we suggest that this developed material could be implemented widely.

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