In this study,functional near-infrared spectroscopy(fNIRS)is utilized to measure the hemodynamic responses(HRs)in the visual cortex of 14 subjects(aged 22–34 years)viewing the primary red,green,and blue(RGB)colors di...In this study,functional near-infrared spectroscopy(fNIRS)is utilized to measure the hemodynamic responses(HRs)in the visual cortex of 14 subjects(aged 22–34 years)viewing the primary red,green,and blue(RGB)colors displayed on a white screen by a beam projector.The spatiotemporal characteristics of their oxygenated and deoxygenated hemoglobins(HbO and HbR)in the visual cortex are measured using a 15-source and 15-detector optode con¯guration.To see whether the activation maps upon RGB-color stimuli can be distinguished or not,the t-values of individual channels are averaged over 14 subjects.To¯nd the best combination of two features for classi¯cation,the HRs of activated channels are averaged over nine trials.The HbO mean,peak,slope,skewness and kurtosis values during 2–7 s window for a given 10 s stimulation period are analyzed.Finally,the linear discriminant analysis(LDA)for classifying three classes is applied.Individually,the best classi¯cation accuracy obtained with slope-skewness features was 74.07%(Subject 1),whereas the best overall over 14 subjects was 55.29%with peak-skewness combination.Noting that the chance level of 3-class classi¯cation is 33.33%,it can be said that RGB colors can be distinguished.The overall results reveal that fNIRS can be used for monitoring purposes of the HR patterns in the human visual cortex.展开更多
基金the China Scholarship Council(CSC)and the Convergence Technology Development Program for Bionic Arm through the National Research Foundation of Korea under the auspices of the Ministry of Science,ICT&Future Planning,Republic of Korea(grant no.2016M3C1B2912986).
文摘In this study,functional near-infrared spectroscopy(fNIRS)is utilized to measure the hemodynamic responses(HRs)in the visual cortex of 14 subjects(aged 22–34 years)viewing the primary red,green,and blue(RGB)colors displayed on a white screen by a beam projector.The spatiotemporal characteristics of their oxygenated and deoxygenated hemoglobins(HbO and HbR)in the visual cortex are measured using a 15-source and 15-detector optode con¯guration.To see whether the activation maps upon RGB-color stimuli can be distinguished or not,the t-values of individual channels are averaged over 14 subjects.To¯nd the best combination of two features for classi¯cation,the HRs of activated channels are averaged over nine trials.The HbO mean,peak,slope,skewness and kurtosis values during 2–7 s window for a given 10 s stimulation period are analyzed.Finally,the linear discriminant analysis(LDA)for classifying three classes is applied.Individually,the best classi¯cation accuracy obtained with slope-skewness features was 74.07%(Subject 1),whereas the best overall over 14 subjects was 55.29%with peak-skewness combination.Noting that the chance level of 3-class classi¯cation is 33.33%,it can be said that RGB colors can be distinguished.The overall results reveal that fNIRS can be used for monitoring purposes of the HR patterns in the human visual cortex.
