Stimulus reconstruction decodes the listener's auditory attention through the greater neural tracking of the attended speech over the unattended stream. While acoustic features of speech are vital to the listening task and comprehension, very few studies have analyzed the effects of acoustic features of speech on stimulus reconstruction. This paper investigates approaches of stimulus reconstruction, where correlations between the neurally decoded and actual speech envelopes are calculated from specific speech segments, varying in transient levels as measured by spectral transition measures. Additionally, two methods of calculating correlations were adopted enabling analysis of the effects of relatively lower and higher frequency components of the speech envelope. Correlation after concatenation analysis showed that STM level of only the attended speech affected decoding performance, hinting at a top-down attentional effect. A bottom-up effect of salient aspects of speech momentarily dominating neural entrainment was also inferred from the weighted mean of multiple correlations. Future studies on the link between acoustic features of speech and its corresponding neural tracking behavior are suggested.

Brain‐computer interface (BCI) enables people who cannot move their own body freely to manipulate machines and helps their communication and life. Recent brain‐computer interface (BCI) uses multimodal stimuli to increase bit rate of the system, so it is important to reveal when and which part of the brain part is activated to discriminate target stimuli. Although magnetoencephalography (MEG) measures brain activity with high spatial and temporal resolution, there are a few indexes to estimate spatiotemporal locality of response. We propose an index to estimate spatiotemporal locality of response to multimodal stimuli of an oddball paradigm from magnetoencephalography (MEG) signals. The validity of proposed index is demonstrated by simulation. Discrimination task was conducted with different ratio of target/nontarget stimuli with visual and auditory location. Response to visual target stimuli was strong and made no spatiotemporal difference, so visual dominance was implied.

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