نتایج جستجو برای: پتانسیل برانگیخته بینایی vep
تعداد نتایج: 22554 فیلتر نتایج به سال:
Dynamic random dot fusion, stereopsis and stereoacuity were evaluated in 149 healthy, fullterm infants, using both forced-choice preferential looking (FPL) and steady-state visual evoked potential (VEP) protocols. Few infants aged 2-3 months demonstrated fusion or stereopsis in either the FPL or VEP protocol; most infants aged 5 months and older demonstrated fusion and stereopsis in both protoc...
Visually-evoked potentials (VEPs) were recorded from infants between the ages of 2 and 11 months in response to 2.5 c/deg main axis and oblique square wave gratings. The oblique effect first appears at 3 months of age; some infants showed smaller VEP amplitude and/or longer VEP latency for obliquely oriented gratings. Regarding the age of onset of the oblique effect, VEP data from this study ag...
در پایان نامه حاضر پتانسیل وارد بر یک اتم دو ترازی و نیز پتانسیل برهمکنش بین دو اتم دو ترازی که یکی در حالت برانگیخته و دیگری در حالت پایه در معرض میدان الکترومغناطیسی در یک محیط شبه کاواک قرار دارند، محاسبه شده است. این کار در حضور اجسام مغناطوالکتریک اتلافی، در چرچوب جفت شدگی قوی و الکترودینامیک کوانتومی ماکروسکوپی صورت گرفته است. ابتدا با استفاده از طرح کوانتش که وجود اجسام مغناطوالکتریک نیز...
We propose a novel framework to reduce background electroencephalogram (EEG) artifacts from multitrial visual-evoked potentials (VEPs) signals for use in brain-computer interface (BCI) design. An algorithm based on cyclostationary (CS) analysis is introduced to locate the suitable frequency ranges that contain the stimulus-related VEP components. CS technique does not require VEP recordings to ...
PURPOSE The visual evoked potential (VEP) is a frequently used noninvasive measurement of visual function. However, high-amplitude variability has limited its potential for evaluating axonal damage in both laboratory and clinical research. This study was conducted to improve the reliability of VEP amplitude measurement in rats by using electroencephalogram (EEG)-based signal correction. METHO...
Dynamic random dot correlograms (DRDCs) are binocular stimuli that evoke a percept and a visual evoked potential (VEP) only in case of a mature and functional binocular system. DRDC-VEP is a method extensively used to study cortical binocularity in human infants and nonverbal children. Although the DRDC-VEP was invented 3 decades ago, neither the fundamental parameters, including contrast, of t...
The visual evoked potential (VEP) generated by the amblyopic visual system demonstrates reduced amplitude, prolonged latency, and increased variation in response timing (phase-misalignment). This study examined VEPs before and after occlusion therapy (OT) and whether phase-misalignment can account for the amblyopic VEP deficits. VEPs were recorded to 0.5-4cycles/degree gratings in 10 amblyopic ...
Single visual evoked potentials (VEP) are very weak and noisy signals. For this reason, powerful extraction tools are needed to improve their clinical use. In this paper, we present two methods for filtering VEP: a linear one, based on the adaptive noise canceller scheme where the input signals represent successive recorded VEP, and a new non-linear method which exploits the neural network prop...
The present study compares behaviour-dependent and physostigmine-induced changes of the visual evoked potential (VEP) in unrestrained rats to provide further indications on the role of acetylcholine in the behavioural VEP modulation. On 30 rats the VEPs on the pial surface of the primary visual cortex were investigated during five spontaneous behavioural states. Physostigmine, carbachol and nic...
Cardiac pulse-related artifacts in the EEG recorded simultaneously with fMRI are complex and highly variable. Their effective removal is an unsolved problem. Our aim is to develop an adaptive removal algorithm based on the matching pursuit (MP) technique and to compare it to established methods using a visual evoked potential (VEP). We recorded the VEP inside the static magnetic field of an MR ...
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