Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"Visual evoked potential"”.
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Visual Evoked Potential Measures of Blur Adaptation
… blur effects through the measurement of the visual evoked potential (VEP). VEP measurements were taken over time as subjects were exposed to a reversing sine-wave grating both with blur and with blur adaptation. The VEP measurement gave insight about the visual acuity, which can be used to …
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Stimulus intensity effects on the steady-state visual evoked potential
… that the amplitude of the steady-state visual evoked potential (SSVEP), a neural response to repetitive visual stimuli, is positively correlated with stimulus intensity. SSVEPs are often used as input mechanisms for brain-computer interfaces (BCIs), systems that establish a direct …
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A distance adaptable brain-computer interface based on steady-state visual evoked potential
… BCIs include motor sensory rhythm, slow cortical potential, P300 and steady-state visual evoked potential (SSVEP). Compared to the other EEG based BCI paradigms, SSVEP based BCI has the advantage of high information transfer rate, high detection rate, less user training time required and commands …
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Contrast adaptation reveals increased organizational complexity of chromatic processing in the visual evoked potential
… directions in color space. The chromatic visual evoked potential (crVEP) has demonstrated chromatic processing selective for cardinal axes of color space. However, crVEP evidence for higher-order color mechanisms is lacking. The present study aimed to assess the contribution of lower and …
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Comparison of tripolar and traditional recording of the pattern-reversal visual evoked potential: signal and noise
… noise reduction in recording muscle-related potentials and seizure detection. However, less has been done to study the efficacy of this promising technology for studying the visual system. Here, we investigate TCRE tEEG recording to evaluate any potential drawbacks or benefits over …
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The Development of Flash Visual Evoked Potential Techniques for the Diagnosis of Visual Disorders with Dense Opacities of the Optic Media
Visual evoked potentials (VEP)were recorded in a large normal population. Significant age differences were found, and the P2 component (latency 116 m.sec.) was the most consistent component of the VEP both between and within the individuals. The validity of the normal VEP criteria were tested in …
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Pattern Reversal Chromatic VEPs like Onsets, are unaffected by Attentional Demand
Attention has been shown to modulate the visual evoked potential (VEP) recorded to reversing achromatic patterns. However, the chromatic onset VEP appears to be robust to attentional shifts. Functional magnetic resonance imaging (fMRI) responses to both chromatic and achromatic reversing patterns …
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Visual Discomfort and Visual Function: Colour and Contrast
In six studies, vision and visual discomfort were investigated in individuals who experienced migraine or reading difficulty. Contrast discrimination thresholds were measured at two pedestal contrasts (10% and 50%) in volunteers with migraine with aura (MA), without aura (MO) and controls (C).There …
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Top-down Modulation of the Chromatic VEP with Hypnotic Suggestion
AbstractVisual perception is composed of both bottom-up (stimulus driven) and top-down (feedback) processes. It has been demonstrated that directed spatial attention enhances processing of attended stimuli, inhibits non-attended stimuli, and increases baseline activity in portions of cortex …
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The effects of selective attention on chromatic processing; pattern-onset VEP responses
… behavioral studies show that attention improves visual processing. Studies of chromatic steady-state and pattern-reversal visual evoked potentials (VEPs) support this. Typically in these studies VEP stimuli are displayed at one spatial location while distracter stimuli are displayed at a …
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Applications of sequential hypothesis testing to the development of non-invasive brain-computer interfaces
… classification method for use in a steady-state visual evoked potential (SSVEP)-based BCI. Instead of relying on a fixed window-length strategy—where a pre-specified amount of data is collected before classification is attempted—a sequential probability ratio test is used and data is collected …
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Functional aspects of blur adaptation in human vision. A study of the mechanism of blur adaptation in human vision - its origin and scope evidenced using subjective and objective procedures.
Sensory adaptation to blur improves visual acuity under defocused conditions. This phenomenon has been successfully demonstrated using subjective measures of acuity and is known as blur adaptation. This study investigates aspects of the mechanism of blur adaptation in human vision using subjective …
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A novel visual stimulation paradigm: exploiting individual primary visual cortex geometry to boost steady state visual evoked potentials (SSVEP)
<p>The steady-state visual evoked potential (SSVEP) is an electroencephalographic response to flickering stimuli generated in significant part by activity in primary visual cortex (V1). SSVEP signal-to-noise ratio is generally low for stimuli that are located in the visual periphery, at frequencies …
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An Electrophysiological Examination of Visuomotor Activity Elicited by Visual Object Affordances
… Response Compatibility (SRC) have suggested that visual action information such as object affordance yields rapid and concurrent activation of visual and motor brain areas, but has rarely provided direct evidence for this proposition. This thesis examines some of the key claims from the affordance …