Retinotopic and topographic analyses with gaze restriction for steady-state visual evoked potentials

Zhang, Nannan; Liu, Yadong; Yin, Erwei; Deng, Baosong; Cao, Lu; Jiang, Jun; Zhou, Zongtan; Hu, Dewen

doi:10.1038/s41598-019-41158-5

Cited by 16 publications

(24 citation statements)

References 32 publications

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“…First, targets located at the bottom of the interface ("4", "8", "0", "S") achieved relatively low accuracies compared to the remaining symbols. This finding is consistent with a recent study [25] in which stimuli below the horizontal midline of the visual field were found to evoke weaker responses than those above. This suggests a possible way for user interface optimization: adding more stimuli at the bottom.…”

Section: Discussionsupporting

confidence: 93%

A Spatially-Coded Visual Brain-Computer Interface for Flexible Visual Spatial Information Decoding

Chen

Wang

Maÿe

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

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Conventional visual BCIs, in which control channels are tagged with stimulation patterns to elicit distinguishable brain patterns, has made impressive progress in terms of the information transfer rates (ITRs). However, less development has been seen with respect to user experience and complexity of the technical setup. The requirement to tag each of targets by a unique stimulus substantially limits the flexibility of conventional visual BCI systems. A method for decoding the targets in the environment flexibly was therefore proposed in the present study. A BCI speller with thirteen symbols drawn on paper was developed. The symbols were interspersed with four flickers with distinct frequencies, but the user did not have to gaze at flickers. Rather, subjects could spell a sequence by looking at the symbols on the paper. In a cue-guided spelling task, the average offline and online accuracies reached 89.3±7.3% and 90.3±6.9% for 13 subjects, corresponding to ITRs of 43.0±7.4 bit/min and 43.8±6.8 bit/min. In an additional free-spelling task for seven out of thirteen subjects, an accuracy of 92.3±3.1% and an ITR of 45.6±3.3 bit/min were achieved. Analysis of a simulated online system showed the possibility to reach an average ITR of 105.8 bit/min by reducing the epoch duration from 4 to 1 second. Reliable BCI control is possible by gazing at targets in the environment instead of dedicated stimuli which encode control channels. The proposed method can drastically reduce the technical effort for visual BCIs and thereby advance their applications outside the laboratory.

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Section: Discussionsupporting

confidence: 93%

A Spatially-Coded Visual Brain-Computer Interface for Flexible Visual Spatial Information Decoding

Chen

Wang

Maÿe

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

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“…This phenomenon has been observed in previous SSVEP BCI studies as well [16,25,26]. What is more, it should be noted that the stimulus in this study was not presented in the center of the visual field, leading to a smaller visual burden but relatively weak SSVEP responses [19,27]. As suggested in a previous high-frequency SSVEP study about BCI demographics, the relatively weaker response may result in a larger individual difference [28].…”

Section: Discussionsupporting

confidence: 79%

Simultaneous Decoding of Eccentricity and Direction Information for a Single-Flicker SSVEP BCI

et al. 2019

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The feasibility of a steady-state visual evoked potential (SSVEP) brain–computer interface (BCI) with a single-flicker stimulus for multiple-target decoding has been demonstrated in a number of recent studies. The single-flicker BCIs have mainly employed the direction information for encoding the targets, i.e., different targets are placed at different spatial directions relative to the flicker stimulus. The present study explored whether visual eccentricity information can also be used to encode targets for the purpose of increasing the number of targets in the single-flicker BCIs. A total number of 16 targets were encoded, placed at eight spatial directions, and two eccentricities (2.5° and 5°) relative to a 12 Hz flicker stimulus. Whereas distinct SSVEP topographies were elicited when participants gazed at targets of different directions, targets of different eccentricities were mainly represented by different signal-to-noise ratios (SNRs). Using a canonical correlation analysis-based classification algorithm, simultaneous decoding of both direction and eccentricity information was achieved, with an offline 16-class accuracy of 66.8 ± 16.4% averaged over 12 participants and a best individual accuracy of 90.0%. Our results demonstrate a single-flicker BCI with a substantially increased target number towards practical applications.

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“…We will further explore SSEVP responses under overt and covert attention with dense spatial resolution with similar visual angle ranges [5]. With covert spatial attention modulating SSVEP responses reliably, SSVEP BCI applications can go beyond conventional visual speller and communication.…”

Section: Discussionmentioning

confidence: 99%

“…The gaze shifts, overt spatial attention are not always workable for certain subjects and test conditions for SSVEP BCI. Gaze independent BCI is highly desirable, [5].…”

Section: Introductionmentioning

confidence: 99%

Effects of Stimulus Spatial Resolution on SSVEP Responses under Overt and Covert Attention

Wai

Lee

Yang

et al. 2020

2020 42nd Annual International Conference of the IEEE Engineering in Medicine &Amp; Biology Society (EMBC)

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Steady-State Visual Evoked Potentials (SSVEP) Brain-Computer Interface (BCI) relies on overt spatial attention to exhibit reliable steady-state responses. There is a promising potential to employ the SSVEP paradigm in with vision research and clinical use, for instance, for visual field assessment. In this study, we investigate the SSVEP characteristics with different the spatial attentions, different number of stimuli and different viewing/visual angles. We collected data from eleven subjects in three experiment sessions, lasting about forty minutes, including the setup and calibration. Our evaluation results show similar SSVEP responses between overt and covert attention in multiple stimuli scenarios in most of the visual angles. We do not find any significant differences in SSVEP responses in visual angles between single and multi stimuli in covert attention. From this study, we found that reliable SSVEP responses can be achieved with covert spatial attention regardless of visual angles and stimulus spatial resolution.

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Retinotopic and topographic analyses with gaze restriction for steady-state visual evoked potentials

Cited by 16 publications

References 32 publications

A Spatially-Coded Visual Brain-Computer Interface for Flexible Visual Spatial Information Decoding

A Spatially-Coded Visual Brain-Computer Interface for Flexible Visual Spatial Information Decoding

Simultaneous Decoding of Eccentricity and Direction Information for a Single-Flicker SSVEP BCI

Effects of Stimulus Spatial Resolution on SSVEP Responses under Overt and Covert Attention

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