Investigation of neuropsychological processes in music perception using magnetoencephalography.

我们的研究是在以下四个主要主题下进行的，并对结果进行了简要说明。(1)听觉后向掩蔽和脑磁图掩蔽通过频率选择性和时间分辨率对音乐感知有显著影响。此外，最近研究发现，向后掩蔽的数量与儿童语言能力的发展有关，这使得对其的研究变得更加重要。我们研究了脑磁图对引起后向掩蔽的刺激的反应。结果表明，N1m峰值幅值对信号的内部响应与掩模之间存在一定的非线性关系。我们正在利用后向掩蔽实验的行为结果提出的时间窗口来构建这种现象的模型。我们特别发现，对于两个具有小秒音程的纯音，在音调开始后200-400 ms左右，诱发磁场在直流分量上叠加了更高的频率分量（20-40Hz）。我们正在寻找使用许多主题的这些组件的信号源。我们还注意到这种较长的延迟成分与诱发磁场之间的相似性，这些成分与40赫兹调制啁啾或纯音相似。(3)旋律感知、工作记忆和脑电反应我们准备了几个由三个音符组成的短语，并以类似实验的方式呈现给被试，以研究工作记忆。诱发磁场与受试者在记忆任务中的难度有关。(4) MEG 40 Hz分量的相位同步。本实验与(2)相关，如上所述。当受试者听到40 /s调制的250-500 Hz音调时，测量了40 Hz分量的相位同步。提出了一种描述相动力学的模型。

Our research has been done under the four main topics given below with brief descriptbion of the results.(1)Auditory backward masking and MEG Auditory masking is considered to have significant bearing on musical perception through frequency selectivity and time resolution. Furthermore, it has been recently found out that the amount of backward masking is related to the development of language ability of children, which makes its research all the more important. We investigated MEG responses to stimuli causing backward masking. The results show for example that the N1m peak amplitudes demonstrate some nonlinear relationship between the internal responses to signal and to masker. We are constructing a model for this phenomenon utilizing the time window proposed for behavioral results of backward masking experiments.(2)MEG responses to dissonant chords We found in particular, that for two pure tones with the minor second interval, evoked magnetic fields show higher frequency components (20-40Hz) superimposed on a DC component around 200-400 ms after the onset of the tones. We are looking for signal sources for these components using many subjects. We also note the similarity between this longer latency components with the evoked magnetic fields to 40-Hz modulated chirps or pure tones.(3)Melody perception, working memory and MEG responses We prepared several phrases composed of three notes and presented them to subjects in a similar manner to experiments for investigation of working memory. The evoked magnetic fields were related to the difficulty in memory tasks imposed on the subjects.(4)Phase synchronization in the MEG 40 Hz component This experiment is related to (2)as described. We measured the synchronization of the phases of 40 Hz component when the subject hears 250-500 Hz tone modulated 40 /s. A model describing the dynamics of the phase has been proposed.