Search results for "visual"
showing 10 items of 7386 documents
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…
On the flexibility of letter position coding during lexical processing: Evidence from eye movements when reading Thai
2012
Previous research supports the view that initial letter position has a privileged role in comparison to internal letters for visual-word recognition in Roman script. The current study examines whether this is the case for Thai. Thai is an alphabetic script in which ordering of the letters does not necessarily correspond to the ordering of a word's phonemes. Furthermore, Thai does not normally have interword spaces. We examined whether the position of transposed letters (internal, e.g., porblem, vs. initial, e.g., rpoblem) within a word influences how readily those words are processed when interword spacing and demarcation of word boundaries (using alternatingbold text) is manipulated. The …
The widening of the gaze cone in patients with social anxiety disorder and its normalization after CBT
2013
Gaze plays a crucial role in social interactions. Social Anxiety Disorder (SAD), which is associated with severe impairment of social interactions, is thus likely to exhibit disturbances of gaze perception. We conducted two experiments with SAD-patients and healthy control participants using a virtual head whose gaze could be interactively manipulated. We determined the subjective area of mutual gaze, the so-called gaze cone, and measured it prior to and after a psychotherapeutic intervention (Exp. 1). Patients exhibited larger gaze cones than control subjects. Exp. 2 varied the emotional expression of the virtual head. These data were validated using a real person (professional actor) as s…
Famous face recognition and naming test: a normative study.
2003
Tests of famous face recognition and naming, and tasks assessing semantic knowledge about famous people after presentation either of their faces or their names are often used in the neuropsychological examination of aphasic, amnesic and demented patients. A total of 187 normal subjects took part in this study. The aim was to collect normative data for a newly devised test including five subtests: famous face naming, fame judgement after face presentation and after name presentation, semantic knowledge about famous people after face presentation and after name presentation. Norms were calculated taking into account demographic variables such as age, sex and education and adjusted scores were…
Rifle-balancing in precision shooting:behavioral aspects and psychophysiological implication
2007
This study investigated sharpshooters' strategies to control their rifle stability during the aiming period. Six elite and six pre-elite shooters completed a simulated realistic shooting task (laser rifle), and their performance was evaluated from behavioral and psychophysiological perspectives. The analysis of the rifle's barrel movement, indexing the shooter's behavioral performance, supported the view that rifle-balancing is an essential determinant of superior shooting performance. The psychophysiological data, i.e. the brain slow potentials, suggested that the shooters applied different rifle-hold strategies; the elite shooters concentrated primarily on achieving a stable rifle positio…
Parafoveal previews and lexical frequency in natural reading: Evidence from eye movements and fixation-related potentials.
2019
Participants' eye movements and electroencephalogram (EEG) signal were recorded as they read sentences displayed according to the gaze-contingent boundary paradigm. Two target words in each sentence were manipulated for lexical frequency (high vs. low frequency) and parafoveal preview of each target word (identical vs. string of random letters vs. string of Xs). Eye movement data revealed visual parafoveal-on-foveal (PoF) effects, as well as foveal visual and orthographic preview effects and word frequency effects. Fixation-related potentials (FRPs) showed visual and orthographic PoF effects as well as foveal visual and orthographic preview effects. Our results replicated the early preview …
Visual mismatch negativity (vMMN) is elicited with para-foveal hemifield oddball stimulation: An event-related brain potential (ERP) study.
2017
The visual mismatch negativity (vMMN) is a component of the human event-related brain potential (ERP) that indicates the automatic processing and detection of changes in the visual sensory input. The study tested whether the vMMN was observable when the visual input is restricted to one visual hemifield and, with this, only para-foveal input to one of the two primary sensory cortices in the visual system is available for stimulus processing. The vMMN was elicited by the stimulation restricted to a small portion of the visual field. This demonstrates that in general vMMN elicitation is not confined to stimulations covering a broad range of the visual field or to the propagation of sensory in…
Reliability in perimetric multichannel contrast sensitivity measurements
2014
Background: In this study, the reliability of perimetric contrast sensitivity measurements favouring the achromatic, the red-green and the blue-yellow post-receptorial mechanisms was analysed. Methods: A new technique, multichannel ATD perimetry, provides spatial and temporal stimuli favouring the detection by an achromatic mechanism (A), from a magno or parvocellular origin or by a red-green (RG) chromatic mechanism, with a parvocellular origin or a blue-yellow (BY) mechanism, with a koniocellular origin. The repeatability and reproducibility of contrast sensitivity measurements with these stimuli were studied in a group of 40 healthy subjects. The analysis was carried out on 21 testing po…
CORRELATION OF OPTICAL COHERENCE TOMOGRAPHY PATTERN AND VISUAL RECOVERY AFTER VITRECTOMY WITH SILICONE OIL FOR RETINAL DETACHMENT
2006
PURPOSE: To assess prospectively the features of the macular surface in silicone oil-filled eyes after surgery by analyzing whether silicone oil affects optical coherence tomography (OCT) measurements and their reproducibility and whether a statistical correlation exists between postoperative best-corrected visual acuity (BCVA) and foveal thickness measured by OCT. METHODS: Twenty eyes of 20 patients underwent vitrectomy with silicone oil tamponade for retinal detachment. After vitrectomy, complete ophthalmic examination including determination of BCVA and OCT was performed to quantify the visual recovery and the foveal thickness. RESULTS: Ophthalmoscopy revealed that the retina appeared to…
Association of Birth Weight With Foveolar Thickness in Adulthood: Results From a Population-Based Study
2021
Purpose Low birth weight (BW) is associated with alterations of foveal shape development in childhood—leading to an increased retinal thickness of the fovea. The aim of the present study was to assess whether BW has a long-term effect on foveal retinal thickness (RT) and is still present in adulthood. Methods In the German population-based Gutenberg Health Study (GHS), participants were examined with spectral-domain optical coherence tomography. The association between self-reported BW and RT in the foveolar and perifoveal locations was assessed. Multivariable linear regression analyses with adjustment for potential confounders and grading of foveal hypoplasia were performed. Results Overal…