Search results for "Eye Movements"
showing 10 items of 95 documents
Thalamic infarctions cause side-specific suppression of vestibular cortex activations.
2005
H2O15-PET was performed during caloric vestibular stimulation of the right and left external ears in eight right-handed patients with acute unilateral infarctions or haemorrhages of the posterolateral thalamus (four right, four left). The posterolateral thalamus is the relay station for ipsi- and contralateral ascending vestibular input to the multiple multisensory vestibular cortex areas. The aim of this study was to evaluate the differential effects of unilateral vestibular thalamic lesions on thalamo-cortical projections, right hemispheric dominance and reciprocal inhibitory visual-vestibular interaction, as well as perceptual and ocular motor consequences during caloric irrigation. The …
Can colours be used to segment words when reading?
2015
Rayner, Fischer, and Pollatsek (1998, Vision Research) demonstrated that reading unspaced text in Indo-European languages produces a substantial reading cost in word identification (as deduced from an increased word-frequency effect on target words embedded in the unspaced vs. spaced sentences) and in eye movement guidance (as deduced from landing sites closer to the beginning of the words in unspaced sentences). However, the addition of spaces between words comes with a cost: nearby words may fall outside high-acuity central vision, thus reducing the potential benefits of parafoveal processing. In the present experiment, we introduced a salient visual cue intended to facilitate the process…
Eye Movement Involvement in Parry-Romberg Syndrome: A Clinicopathologic Case Report
2008
We report the case of a 38-year-old woman who developed a progressive bilateral disease in which the eye motility disorder-diplopia-is the outstanding feature over a period of 12 years. The muscle biopsy of the medial rectus muscle did not show any trace of striated muscle. To the best of our knowledge, this is the first pathological report in an affected extraocular muscle of a patient with Parry-Romberg syndrome (PRS). Previous rare reports of diplopia in PRS have been attributed to enophthalmos, progressive atrophy of the orbit, ocular motor nerve dysfunction, or mechanical restrictions.
Dissociating spatial and letter-based word length effects observed in readers’ eye movement patterns
2011
In previous eye movement research on word length effects, spatial width has been confounded with the number of letters. McDonald (2006) unconfounded these factors by rendering all words in sentences in constant spatial width. In the present study, the Arial font with proportional letter spacing was used for varying the number of letters while equating for spatial width, while the Courier font with monospaced letter spacing was used to measure the contribution of spatial width to the observed word length effect. Number of letters in words affected single fixation duration on target words, whereas words’ spatial width determined fixation locations in words and the probability of skipping a wo…
Strategic inhibition of distractors with visual working memory contents after involuntary attention capture
2017
AbstractPrevious research has suggested that visual working memory (VWM) contents had a guiding effect on selective attention, and once participants realized that the distractors shared the same information with VWM contents in the search task, they would strategically inhibit the potential distractors with VWM contents. However, previous behavioral studies could not reveal the way how distractors with VWM contents are inhibited strategically. By employing the eye-tracking technique and a dual-task paradigm, we manipulated the probability of memory items occurring as distractors to explore this issue. Consistent with previous behavioral studies, the results showed that the inhibitory effect…
Eyes open and eyes closed as rest conditions: impact on brain activation patterns
2003
The patterns of associated brain activations during eyes-open and eyes-closed states in complete darkness considerably differ in fMRI. An "interoceptive" state with the eyes closed is characterized by visual cortex activation, while an "exteroceptive" state with the eyes open is characterized by ocular motor system activity. The impact of the chosen rest condition (eyes open or eyes closed in complete darkness) on the pattern of brain activations during visual stimulation was evaluated in 14 healthy volunteers. During fixation or dim light room illumination, the activation of the visual cortex was larger with the eyes-open rest condition than with the eyes-closed rest condition; however, ac…
Wertheim’s hypothesis on ‘highway hypnosis’: empirical evidence from a study on motorway and conventional road driving
2003
This paper aims to study the phenomenon known as 'highway hypnosis' or 'driving without attention mode', which has been defined as a state showing sleepiness signs and attention slip resulting from driving a motor vehicle for a long period in a highly predictable environment with low event occurrence, this being the case with motorways and very familiar roads [Highway hypnosis: a theoretical analysis. In: Gale, A.G., Brown, I.D., Haslegrave, C.M., Moorhead, I., Taylor, S. (Eds.), Vision in Vehicles-III. Elsevier, North-Holland, pp. 467-472]. According to Wertheim's hypothesis on 'highway hypnosis', long-term driving on motorways and conventional roads, e.g. main roads, secondary roads--impl…
Attentional capture by emotional scenes across episodes in bipolar disorder: Evidence from a free-viewing task
2015
We examined whether the initial orienting, subsequent engagement, and overall allocation of attention are determined exogenously (i.e. by the affective valence of the stimulus) or endogenously (i.e. by the participant's mood) in the manic, depressive and euthymic episodes of bipolar disorder (BD). Participants were asked to compare the affective valence of two pictures (happy/threatening/neutral [emotional] vs. neutral [control]) while their eye movements were recorded in a free-viewing task. Results revealed that the initial orienting was exogenously captured by emotional images relative to control images. Importantly, engagement and overall allocation were endogenously captured by threate…
Inhibitory Control for Emotional and Neutral Scenes in Competition: An Eye-Tracking Study in Bipolar Disorder
2017
This study examined the inhibitory control of attention to social scenes in manic, depressive, and euthymic episodes of bipolar disorder (BD). Two scenes were simultaneously presented (happy/threatening/neutral [target] versus control). Participants were asked either to look at the emotional pictures (i.e., attend-to-emotional block) or to avoid looking at the emotional pictures (i.e., attend-to-neutral block) while their eye movements were recorded. The initial orienting (latency and percentage of first fixation) and subsequent attentional engagement (gaze duration) were computed. Manic patients showed a higher percentage of initial fixations on happy scenes than on the other scenes, regar…
Performing allocentric visuospatial judgments with induced distortion of the egocentric reference frame: an fMRI study with clinical implications
2003
The temporary improvement of visuospatial neglect during galvanic vestibular stimulation (Scand. J. Rehabil. Med. 31 (1999)117) may result from correction of the spatial reference frame distorted by the responsible lesion. Prior to an investigation of the neural basis of this effect in neurological patients, exploration of the neural mechanisms underlying such procedures in normals is required to provide insight into the physiological basis thereof. Despite their clinical impact, the neural mechanisms underlying the interaction of galvanic (and other) vestibular manipulations with visuospatial processing (and indeed the neural bases of how spatial reference frames are computed in man) remai…