All participants were native Japanese speakers with higher than college level education. The study protocol was approved by the ethics committee of Osaka City University and was conducted in accordance with the principles of the Declaration of Helsinki, with written informed consent obtained from all participants prior to enrollment in the study. This study comprised three experimental sessions (Story A session, Story B session, and Story C session) (Fig. 6A). After enrollment, participants
were randomly assigned to three groups in a single-blinded, three-crossover fashion to consecutively Adriamycin in vivo undergo these three experimental sessions. They were requested to carefully listen to and understand three spoken Japanese stories (Story A, Story B, and Story C) with their eyes closed. The stories were constructed of recorded narratives in
which 2–4 syllables of the latter portion of spoken keywords, which seemed to contribute to the understanding of the stories, were replaced by 300-ms white-noise stimuli with an inter-stimulus interval of 1.6–20.3 s (Fig. 6B). Two of the three stories (Story A and Story B) were played forward and one story (Story C) was played in reverse (Story C was the reverse version of Story A). All spoken words consisted of the same digitally recorded female voice. Sound pressure, frequency range, and duration of the spoken words and white noise were adjusted using Protirelin Adobe Premier Elements AZD2281 cell line (Adobe Systems, Tokyo, Japan) and presented via an MEG-compatible sound system (Model ER-2; Etymotic Research, Elk Grove Village, IL) using Windows Media Player 9 (Microsoft Japan, Tokyo, Japan) implemented on a personal computer (Precision PWS390; Dell Computer, TX). The Story A session involved 50 white-noise stimuli with a total duration of 311 s and the Story B session involved 68 white-noise stimuli with a total duration of 412 s, and the Story A session and the Story B session constituted a forward condition. The
Story C session consisted of 101 white-noise stimuli with a total duration of 311 s, and the Story C session constituted a reverse condition. We recorded MEG during these three experimental sessions, and white noise was used as a stimulus. The reverse condition was performed as a control, and we compared MEG responses to white-noise stimuli during the forward condition with those during the reverse condition using time–frequency analyses, in order to investigate neural activations related to phonemic restoration. Immediately after the end of the Story A and Story B sessions, the participants were asked 8 questions about the contents of each story to assess the objective story-comprehension level. Each question comprised 4 choices with one correct answer.