Momentary fluctuations in attention (perceptual accuracy) correlate with neural activity fluctuations in primate visual areas. Yet, the link between such momentary neural fluctuations and attention state remains to be shown in the human brain. We investigate this link using a real-time cognitive brain machine interface (cBMI) based on steady state visually evoked potentials (SSVEPs): occipital EEG potentials evoked by rhythmically flashing stimuli. Tracking momentary fluctuations in SSVEP power, in real-time, we presented stimuli time-locked to when this power reached (predetermined) high or low thresholds. We observed a significant increase in discrimination accuracy (d') when stimuli were triggered during high (versus low) SSVEP power epochs, at the location cued for attention. Our indicate a direct link between attention’s effects on perceptual accuracy and and neural gain in EEG-SSVEP power, in the human brain. To identify efficient acquisition software, we compared the round-trip (closed-loop) delay for four 34 acquisition software: ActiView, Lab Streaming Layer, OpenVibe and Fieldtrip (Fig. 1B). We measured 35 round-trip delay by varying the EEG+event packet size, across different sampling frequencies, fit a 36 line to the data, and estimated the intercept, which is a measure of the overhead. We observed that Fieldtrip produced the least overhead of 10.98 ± 0.50 ms. EEG data recording: Scalp EEG recordings were performed with 41 occipital electrodes out of 39 the total 128 electrodes. The data was streamed in real-time using the Fieldtrip buffer at 128 Hz. EEG 40 data was also stored at 4096 Hz for offline analyses. Spectral analysis was performed using Chronux 41 2.12 toolbox EEGLAB 13.6.5b functions were used to generate the topographical plots. Dense-array Studies). Finally, the EEG data was re-referenced to the average reference. higher, across the population, for AI-high trials as compared to AI-low trials (p < 0.01). We did not
With a cognitive brain-machine interface, we show a direct link between attentional effects on perceptual accuracy and neural gain in EEG-SSVEP power, in the human brain.