Search results for "Ocular"
showing 10 items of 1219 documents
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…
Repetitive TMS of cerebellum interferes with millisecond time processing
2007
Time processing is important in several cognitive and motor functions, but it is still unclear how the human brain perceives time intervals of different durations. Processing of time in millisecond and second intervals may depend on different neural networks and there is now considerable evidence to suggest that these intervals are possibly measured by independent brain mechanisms. Using repetitive transcranial magnetic stimulation (rTMS), we determined that the cerebellum is essential in explicit temporal processing of millisecond time intervals. In the first experiment, subjects' performance in a time reproduction task of short (400-600 ms) and long (1,600-2,400 ms) intervals, were evalua…
Hemispheric cerebellar rTMS to treat drug-resistant epilepsy: case reports.
2005
Electrical stimulation of the cerebellar cortex by implanted electrodes has been shown to ameliorate refractory epilepsy. We investigated the potential therapeutic role of high-frequency cerebellar rTMS in patients affected by refractory epilepsy due to single or multiple foci. Six patients, three with single and three with multiple epileptic foci, underwent 20 rTMS sessions. Each session was given daily, excluding weekends, and consisted of two trains of 50 stimuli (5 Hz frequency and 90% motor threshold intensity), separated by 50s interval. rTMS was delivered through a focal coil (2 cm below and lateral to the inion) bilaterally in patients with multiple foci (two trains for hemisphere: …
Changes in cerebellar activation pattern during two successive sequences of saccades
2002
The changes in the cerebellar activation pattern of two successive fMRI scanning runs were determined for visually guided to‐and‐fro saccades in 12 healthy volunteers familiar with the study paradigm. Group and single subject‐analyses revealed a constant activation of the paramedian cerebellar vermis (uvula, tonsils, tuber, folium/declive), which reflects constant ocular motor activity in both runs. A significant decrease in activation of the cerebellar hemispheres found in the second run is best explained by either a decrease in attention or the effects of motor optimization and learning. The significant, systematic changes of the cerebellar activation pattern in two successive runs were n…
Increased facilitation of the primary motor cortex following 1 Hz repetitive transcranial magnetic stimulation of the contralateral cerebellum in nor…
2005
Connections between the cerebellum and the contralateral motor cortex are dense and important, but their physiological significance is difficult to measure in humans. We have studied a group of 10 healthy subjects to test whether a modulation of the excitability of the left cerebellum can affect the excitability of the contralateral motor cortex. We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz frequency to transiently depress the excitability of the left cerebellar cortex and paired-pulse TMS testing of intracortical inhibition (ICI) and intracortical facilitation (ICF) to probe the excitability of cortico-cortical connections in the right motor cortex. The cortical sile…
Intrasubject repeatability of corneal power, thickness, and wavefront aberrations with a new version of a dual rotating Scheimpflug–Placido system
2014
Purpose To determine the intrasubject repeatability of a recently introduced dual-camera rotating Scheimpflug–Placido imaging system (Galilei G4) in determining corneal thickness, power, and wavefront aberrations in young healthy subjects. Setting University of Valencia, Valencia, Spain. Design Prospective evaluation of diagnostic technology. Methods The study comprised right eyes of 25 subjects aged 20 to 40 years with a spherical equivalent ranging from −4.25 to +1.00 diopters. The central corneal thickness, thinnest point value and location, anterior and posterior surface curvatures, total corneal power, and corneal wavefront aberrations were measured for distance vision using the dual S…
Segregation of areas related to visual working memory in the prefrontal cortex revealed by rTMS.
2002
The functional organization of working memory (WM) in the human prefrontal cortex remains unclear. Storage and processing functions might be segregated in ventral and dorsal areas of the prefrontal cortex, respectively. If so, storage functions might be spared, irrespective of informational domain, following damage or dysfunction in dorsolateral areas. Alternatively, WM and prefrontal function in general might be segregated according to informational domains (e.g. spatial versus object-based information). In the present study we used repetitive transcranial magnetic stimulation (rTMS) to directly test these competing hypotheses. We applied rTMS to transiently and selectively disrupt the fun…
Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials
2014
The neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) have been mostly investigated by peripheral motor-evoked potentials (MEPs). New TMS-compatible EEG systems allow a direct investigation of the stimulation effects through the analysis of TMS-evoked potentials (TEPs).We investigated the effects of 1-Hz rTMS over the primary motor cortex (M1) of 15 healthy volunteers on TEP evoked by single pulse TMS over the same area. A second experiment in which rTMS was delivered over the primary visual cortex (V1) of 15 healthy volunteers was conducted to examine the spatial specificity of the effects. Single-pulse TMS evoked four main components: P30, N45, P60 and N100. M…
Myopia and Cognitive Performance: Results From the Gutenberg Health Study.
2016
Purpose To analyze the association between myopia and cognitive performance. Methods A cohort of the population-based Gutenberg Health Study included 3819 eligible enrollees between 40 and 79 years. We used the Tower of London (TOL) test to assess cognitive performance. Myopia was defined as a spherical equivalent (SE) ≤ -0.5 diopters (D) via noncycloplegic autorefractometry. We conducted linear mixed models with the SE as the dependent variable and the age, sex, duration of education, and TOL score as covariates. Results Complete data were available for 3452 participants (90.4%). The mean TOL score was 14.0 ± 3.9 in the myopes versus 12.9 ± 4.0 in the nonmyopes (P < 0.001). The mean TOL sc…
Inter-joint coordination of posture on a seesaw device
2016
Even though specific adjustments of the multi-joint control of posture have been observed when posture is challenged, multi-joint coordination on a seesaw device has never been accurately assessed. The current study was conducted in order to investigate the multi-joint coordination when subjects were standing on either a seesaw device or on a stable surface, with the eyes open or closed. Eighteen healthy active subjects were recruited. A principal component analysis and a Self-Organizing Maps analysis were performed on the joint angles in order to detect and characterize dominant coordination patterns. Intermuscular EMG coherence was analysed in order to assess the neurophysiological mechan…