Stimulus specificity of a steady-state visual-evoked potential-based brain-computer interface

The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we...

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Bibliographic Details
Published in:Journal of neural engineering 2012-06, Vol.9 (3), p.036008-036008
Main Authors: Ng, Kian B, Bradley, Andrew P, Cunnington, Ross
Format: Article
Language:English
Subjects:
Adult
Algorithms
Beta
Brain - physiology
brain-computer interface
Classification
Data Interpretation, Statistical
Electroencephalography
Electromyography
Electrooculography
Evoked Potentials, Visual - physiology
Female
Human-computer interface
Humans
Male
Optimization
Photic Stimulation
Representations
steady-state visual-evoked potential
Stimuli
stimulus specificity
User-Computer Interface
Visual
Visual Fields
Visual stimuli
Young Adult
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Summary:The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we study the effect that stimulus specificity has on the classification performance of a steady-state visual-evoked potential-based brain-computer interface (SSVEP-BCI). For example, we investigate how closely two visual stimuli can be placed before they compete for neural representation in the cortex and thus influence BCI classification accuracy. We characterize stimulus specificity using the four stimulus parameters commonly encountered in SSVEP-BCI design: temporal frequency, spatial size, number of simultaneously displayed stimuli and their spatial proximity. By varying these quantities and measuring the SSVEP-BCI classification accuracy, we are able to determine the parameters that provide optimal performance. Our results show that superior SSVEP-BCI accuracy is attained when stimuli are placed spatially more than 5° apart, with size that subtends at least 2° of visual angle, when using a tagging frequency of between high alpha and beta band. These findings may assist in deciding the stimulus parameters for optimal SSVEP-BCI design.
ISSN:1741-2560
1741-2552
DOI:10.1088/1741-2560/9/3/036008