2015 年 7 月の行事予定
The 22nd Perceptual Frontier Seminar: Patterns in Mind
Date and time: Friday, 31 July 2015, from 13:00-14:30
1. On the contribution of power-fluctuation factors to speech intelligibility
The present study investigated how power-fluctuation factors extracted from speech signals, represented as 20 power fluctuations incritical-band filters, contribute to speech intelligibility. Nine native Japanese speakers listened to speech-like stimuli resynthesized from the extracted factors, and answered Japanese morae (syllable-like units) they perceived. When the number of factors changed from two to three, their identification performance leaped from 5.4% to 79.6%. This suggests that the first three power-fluctuation factors are critical for speech intelligibility.
2. Neuromagnetic account of how the human brain decides the equality of two intervals
Magnetoenchephalography experiment using unique perceptual phenomenon, Auditory temporal assimilation, revealed that two distinct brain regions are involved in cognitive time management. The right temporo-parietal junction was activated when participants attended to the time intervals to be encoded. The right inferior frontal gyrus was activated when participants compared and decided the equality/inequality of two adjacent empty time intervals. These processes completed immediately after the stimulus presentation.
3. Integration of touch and vision in children, studied with child MEG
We will describe an experiment in which somatosensory evoked field (SEF) was obtained from 3- to 4-year-old children in response to tactile-only and visuotactile stimuli. The data were obtained with the use of child-customsized magneto-encephalography (MEG) equipment. SEF data from preschool children to tactile-only stimuli have been described in only a few articles so far, and, to our knowledge, the present study is the first to describe preschool SEF in response to visuotactile stimuli. The major deflections in the MEG waveform in terms of latencies and source strengths will be described. We first show that the preschool children who participated in the experiment mainly provided an anteriorly-directed M60 as a first major deflection in the waveform---different from an adult-like M50. The second major deflection in the waveform, the M100, was subject to modulatory effects of visual information. This shows that already at preschool age, somatosensory evoked field reflects intermodal connectivity.