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https://www.readbyqxmd.com/read/27913216/spatiotopic-updating-across-saccades-revealed-by-spatially-specific-fmri-adaptation
#1
Scott L Fairhall, Jens Schwarzbach, Angelika Lingnau, Martijn Gerbrand Van Koningsbruggen, David Melcher
Brain representations of visual space are predominantly eye-centred (retinotopic) yet our experience of the world is largely world-centred (spatiotopic). A long-standing question is how the brain creates continuity between these reference frames across successive eye movements (saccades). Here we use functional magnetic resonance imaging (fMRI) to address whether spatially specific repetition suppression (RS) is evident during trans-saccadic perception. We presented two successive Gabor patches (S1 and S2) in either the upper or lower visual field, left or right of fixation...
November 29, 2016: NeuroImage
https://www.readbyqxmd.com/read/27905866/morphological-structure-influences-the-initial-landing-position-in-words-during-reading-finnish
#2
Jukka Hyönä, Ming Yan, Seppo Vainio
The preferred viewing location in words (Rayner, 1979) during reading is near the word center. Parafoveal word length information is utilized to guide the eyes toward it. A recent study of Yan et al. (2014) demonstrated that the word's morphological structure may also be used in saccadic targeting. The study was conducted in a morphologically rich language, Uighur. The present study aimed at replicating their main findings in another morphologically rich language, Finnish. Similarly to Yan et al., it was found that the initial fixation landed closer to the word beginning for morphologically complex than monomorphemic words...
December 1, 2016: Quarterly Journal of Experimental Psychology: QJEP
https://www.readbyqxmd.com/read/27903814/blink-associated-contralateral-eccentric-saccades-as-a-rare-sign-of-unilateral-brain-injury
#3
Ilaria Zivi, Eugenio Bertelli, Giacinta Bilotti, Ignazio Alessandro Clemente, Leopold Saltuari, Giuseppe Frazzitta
OBJECTIVE: To describe a rare sign of unilateral brain injury as a form of unwanted blink-associated contralateral eccentric saccades. METHODS: A 62-year-old patient who underwent an ischemic stroke affecting the entire right middle cerebral artery territory came to our attention 1 year after stroke, manifesting with transient contralateral conjugate gaze deviations associated with spontaneous blinking. We complemented the regular neurologic evaluation with brain MRI, study of evoked potentials, electroneurography of the facial nerve, and infrared video-oculoscopy...
November 30, 2016: Neurology
https://www.readbyqxmd.com/read/27903636/spatiotopic-maps-during-dynamic-head-tilt
#4
Kyriaki Mikellidou, Marco Turi, David Charles Burr
Humans maintain a stable representation of the visual world effortlessly, despite constant movements of the eyes, head and body, across multiple planes. Whereas visual stability in the face of saccadic eye-movements has been intensely researched, fewer studies have investigated retinal image transformations induced by head movements, especially in the frontal plane. Unlike head rotations in the horizontal and sagittal planes, tilting the head in the frontal plane is only partially counteracted by torsional eye-movements, and consequently induces a distortion of the retinal image to which we seem to be completely oblivious...
November 30, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27899887/saccadic-adaptation-alters-the-attentional-field
#5
Farahnaz A Wick, Tyler W Garaas, Marc Pomplun
It is currently unknown whether changes to the oculomotor system can induce changes to the distribution of spatial attention around a fixated target. Previous studies have used perceptual performance tasks to show that adaptation of saccadic eye movements affects dynamic properties of visual attention, in particular, attentional shifts to a cued location. In this study, we examined the effects of saccadic adaptation on the static distribution of visual attention around fixation (attentional field). We used the classic double step adaptation procedure and a flanker task to test for differences in the attentional field after forward and backward adaptation...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27894025/fixating-on-the-size-speed-illusion-of-approaching-railway-trains-what-we-can-learn-from-our-eye-movements
#6
Helen E Clark, John A Perrone, Robert B Isler, Samuel G Charlton
Railway level crossing collisions have recently been linked to a size-speed illusion where larger objects such as trains appear to move slower than smaller objects such as cars. An explanation for this illusion has centred on observer eye movements - particularly in relation to the larger, longer train. A previous study (Clark et al., 2016) found participants tend to make initial fixations to locations around the visual centroid of a moving vehicle; however individual eye movement patterns tended to be either fixation-saccade-fixation type, or smooth pursuit...
November 25, 2016: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/27893991/saclab-a-toolbox-for-saccade-analysis-to-increase-usability-of-eye-tracking-systems-in-clinical-ophthalmology-practice
#7
Laura Cercenelli, Guido Tiberi, Ivan Corazza, Giuseppe Giannaccare, Michela Fresina, Emanuela Marcelli
PURPOSE: Many open source software packages have been recently developed to expand the usability of eye tracking systems to study oculomotor behavior, but none of these is specifically designed to encompass all the main functions required for creating eye tracking tests and for providing the automatic analysis of saccadic eye movements. The aim of this study is to introduce SacLab, an intuitive, freely-available MATLAB toolbox based on Graphical User Interfaces (GUIs) that we have developed to increase the usability of the ViewPoint EyeTracker (Arrington Research, Scottsdale, AZ, USA) in clinical ophthalmology practice...
November 22, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/27893273/spontaneous-rereading-within-sentences-eye-movement-control-and-visual-sampling
#8
Sarah J White, Laura M T Lantz, Kevin B Paterson
Three experiments examine the role of previously read text in sentence comprehension and the control of eye movements during spontaneous rereading. Spontaneous rereading begins with a regressive saccade and involves reinspection of previously read text. All 3 experiments employed the gaze-contingent change technique to modulate the availability of previously read text. In Experiment 1, previously read text was permanently masked either immediately to the left of the fixated word (beyond wordn) or more than 1 word to the left (beyond wordn-1)...
November 28, 2016: Journal of Experimental Psychology. Human Perception and Performance
https://www.readbyqxmd.com/read/27893224/the-influence-of-a-word-s-number-of-letters-spatial-extent-and-initial-bigram-characteristics-on-eye-movement-control-during-reading-evidence-from-arabic
#9
Ehab W Hermena, Simon P Liversedge, Denis Drieghe
The authors conducted 2 eye movement experiments in which they used the typographical and linguistic properties of Arabic to disentangle the influences of words' number of letters and spatial extent on measures of fixation duration and saccade targeting (Experiment 1), and to investigate the influence of initial bigram characteristics on saccade targeting during reading (Experiment 2). In the first experiment, through the use of a proportional font, which is more natural-looking in Arabic compared to monospaced fonts, the authors manipulated the number of letters (5 vs...
November 28, 2016: Journal of Experimental Psychology. Learning, Memory, and Cognition
https://www.readbyqxmd.com/read/27891082/reward-and-behavioral-factors-contributing-to-the-tonic-activity-of-monkey-pedunculopontine-tegmental-nucleus-neurons-during-saccade-tasks
#10
Ken-Ichi Okada, Yasushi Kobayashi
The pedunculopontine tegmental nucleus (PPTg) in the brainstem plays a role in controlling reinforcement learning and executing conditioned behavior. We previously examined the activity of PPTg neurons in monkeys during a reward-conditioned, visually guided saccade task, and reported that a population of these neurons exhibited tonic responses throughout the task period. These tonic responses might depend on prediction of the upcoming reward, successful execution of the task, or both. Here, we sought to further distinguish these factors and to investigate how each contributes to the tonic neuronal activity of the PPTg...
2016: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/27889814/an-fmri-study-of-training-voluntary-smooth-circular-eye-movements
#11
Raimund Kleiser, Cornelia Stadler, Sibylle Wimmer, Thomas Matyas, Rüdiger J Seitz
Despite a large number of recent studies, the promise of fMRI methods to produce valuable insights into motor skill learning has been restricted to sequence learning paradigms, or manual training paradigms where a relatively advanced capacity for sensory-motor integration and effector coordination already exists. We therefore obtained fMRIs from 16 healthy adults trained in a new paradigm that demanded voluntary smooth circular eye movements without a moving target. This aimed to monitor neural activation during two possible motor learning processes: (a) the smooth pursuit control system develops a new perceptual-motor relationship and successfully becomes involved in voluntary action in which it is not normally involved or (b) the saccadic system normally used for voluntary eye movement and which only exhibits linear action skill develops new dynamic coordinative control capable of smooth circular movement...
November 26, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/27884569/eye-spy-with-my-little-eye-motivational-relevance-of-visual-stimuli-guide-eye-movements-at-different-processing-stages
#12
Eugene McSorley, Jayne Morriss, Carien M van Reekum
Visual stimuli may be selected for priority at different stages within the processing stream, depending on how motivationally relevant they are to the perceiver. Here we examine the extent to which individual differences in motivational relevance of task-irrelevant images (spider, crash, baby, food and neutral) guide eye-movements to a simple "follow the cross" task in 96 participants. We found affective images vs. neutral images to be generally more distracting, as shown by faster first saccade latencies and greater deviation in the final landing position from the target cross...
November 21, 2016: Biological Psychology
https://www.readbyqxmd.com/read/27879201/visual-attention-is-available-at-a-task-relevant-location-rapidly-after-a-saccade
#13
Tao Yao, Madhura Ketkar, Stefan Treue, B Suresh Krishna
Maintaining attention at a task-relevant spatial location while making eye-movements necessitates a rapid, saccade-synchronized shift of attentional modulation from the neuronal population representing the task-relevant location before the saccade to the one representing it after the saccade. Currently, the precise time at which spatial attention becomes fully allocated to the task-relevant location after the saccade remains unclear. Using a fine-grained temporal analysis of human peri-saccadic detection performance in an attention task, we show that spatial attention is fully available at the task-relevant location within 30 milliseconds after the saccade...
November 23, 2016: ELife
https://www.readbyqxmd.com/read/27876511/modulation-of-microsaccades-by-spatial-frequency-during-object-categorization
#14
Matt Craddock, Frank Oppermann, Matthias M Müller, Jasna Martinovic
The organization of visual processing into a coarse-to-fine information processing based on the spatial frequency properties of the input forms an important facet of the object recognition process. During visual object categorization tasks, microsaccades occur frequently. One potential functional role of these eye movements is to resolve high spatial frequency information. To assess this hypothesis, we examined the rate, amplitude and speed of microsaccades in an object categorization task in which participants viewed object and non-object images and classified them as showing either natural objects, man-made objects or non-objects...
November 19, 2016: Vision Research
https://www.readbyqxmd.com/read/27872811/failure-to-mobilize-cognitive-control-for-challenging-tasks-correlates-with-symptom-severity-in-schizophrenia
#15
Bengi Baran, F Işık Karahanoğlu, Yigal Agam, Leonidas Mantonakis, Dara S Manoach
Deficits in the adaptive, flexible control of behavior contribute to the clinical manifestations of schizophrenia. We used functional MRI and an antisaccade paradigm to examine the neural correlates of cognitive control deficits and their relations to symptom severity. Thirty-three chronic medicated outpatients with schizophrenia and 31 healthy controls performed an antisaccade paradigm. We examined differences in recruitment of the cognitive control network and task performance for Hard (high control) versus Easy (low control) antisaccade trials within and between groups...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27869764/drivers-visual-search-patterns-during-overtaking-maneuvers-on-freeway
#16
Wenhui Zhang, Jing Dai, Yulong Pei, Penghui Li, Ying Yan, Xinqiang Chen
Drivers gather traffic information primarily by means of their vision. Especially during complicated maneuvers, such as overtaking, they need to perceive a variety of characteristics including the lateral and longitudinal distances with other vehicles, the speed of others vehicles, lane occupancy, and so on, to avoid crashes. The primary object of this study is to examine the appropriate visual search patterns during overtaking maneuvers on freeways. We designed a series of driving simulating experiments in which the type and speed of the leading vehicle were considered as two influential factors...
November 19, 2016: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/27866117/distinguishing-spinocerebellar-ataxia-with-pure-cerebellar-manifestation-from-multiple-system-atrophy-msa-c-through-saccade-profiles
#17
Yasuo Terao, Hideki Fukuda, Shin-Ichi Tokushige, Satomi Inomata-Terada, Akihiro Yugeta, Masashi Hamada, Yoshikazu Ugawa
OBJECTIVE: Patients with spinocerebellar ataxia with pure cerebellar presentation (SCD) and multiple system atrophy (MSA-C) show similar symptoms at early stages, although cerebellofugal pathology predominates in SCD, and cerebellopetal pathology in MSA-C. We studied whether saccade velocity profiles, which reflect the accelerating and braking functions of the cerebellum, can differentiate these two disorders. METHODS: We recorded visually guided (VGS) and memory guided saccades (MGS) in 29 MSA-C patients, 12 SCD patients, and 92 age-matched normal subjects, and compared their amplitude, peak velocity and duration (accelerating and decelerating phases)...
October 29, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27859647/spatial-but-not-oculomotor-information-biases-perceptual-memory-evidence-from-face-perception-and-cognitive-modeling
#18
Andrea L Wantz, Janek S Lobmaier, Fred W Mast, Walter Senn
Recent research put forward the hypothesis that eye movements are integrated in memory representations and are reactivated when later recalled. However, "looking back to nothing" during recall might be a consequence of spatial memory retrieval. Here, we aimed at distinguishing between the effect of spatial and oculomotor information on perceptual memory. Participants' task was to judge whether a morph looked rather like the first or second previously presented face. Crucially, faces and morphs were presented in a way that the morph reactivated oculomotor and/or spatial information associated with one of the previously encoded faces...
November 17, 2016: Cognitive Science
https://www.readbyqxmd.com/read/27856005/mobile-universal-lexicon-evaluation-system-mules-test-a-new-measure-of-rapid-picture-naming-for-concussion
#19
Lucy Cobbs, Lisena Hasanaj, Prin Amorapanth, John-Ross Rizzo, Rachel Nolan, Liliana Serrano, Jenelle Raynowska, Janet C Rucker, Barry D Jordan, Steven L Galetta, Laura J Balcer
OBJECTIVE: This study introduces a rapid picture naming test, the Mobile Universal Lexicon Evaluation System (MULES), as a novel, vision-based performance measure for concussion screening. The MULES is a visual-verbal task that includes 54 original photographs of fruits, objects and animals. We piloted MULES in a cohort of volunteers to determine feasibility, ranges of picture naming responses, and the relation of MULES time scores to those of King-Devick (K-D), a rapid number naming test...
November 4, 2016: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/27855460/-diagnosis-and-current-therapy-of-vestibular-syndromes
#20
Michael Strupp, Thomas Brandt
Vertigo and dizziness are with an annual incidence of more than 10% and a lifetime prevalence of more than 30% among the most frequent symptoms. The keys to the diagnosis are the patient history and the bedside examination: a) for the patient history the time course, type and triggers of symptoms and accompanying symptoms, b) for the clinical examination of the vestibular system the head-impulse test (HIT), the examination for a spontaneous nystagmus, a displacement of subjective visual vertical, a positional nystagmus and the Romberg test, and c) for the differentiation between an acute peripheral and central vestibular lesion the skew deviation, central fixation nystagmus, gaze-evoked nystagmus, saccadic smooth pursuit and a normal HIT...
November 2016: Deutsche Medizinische Wochenschrift
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