FUNCTIONS OF FRONTAL LOBE IN SHORT TERM MEMORY

对高级大脑功能的电生理学的研究已经成为 122通道全头脑磁图的研制成功 (脑磁图)非侵入性磁测量系统 人头外的领域(Lounasmaa等人，IBRO新闻，21(2)，1993)。 在拟议的研究中，我们将利用这个全头系统来检测 健康志愿者额叶自发脑磁图信号 在警觉休息期间，在短期记忆任务期间，最后 在休息期间也是如此。内存任务将由一个 呈现一组要记住的项目(即空间位置 视野中的项目、不同音调或词语的音调 视觉上或听觉上呈现)，然后是保留期， 最后通过测试阶段将旧的和新的项目呈现给 测试识别记忆。自发性脑磁图活动的一致性将 被测量以检测在休息期间额叶的活动 保留期。相干模式中的局部变化将 表明额叶参与了短期记忆。 两个半球的相干图案的不对称性也将是 检查过了。皮质受累的时间动力学将被推断 根据保持过程中连贯模式的时间变化 句号。在之前的连贯研究中不太可能的是，我们还将检查 通过求解信源协方差矩阵来确定信源相干 脑磁图协方差毛利和锋面震源活动检验 保留间隔期间的区域。这项研究可能会开辟一个新的领域 脑磁图在相联函数测量中的应用 无论是健康人还是患有神经疾病的患者。

The study of electrophysiology of higher brain functions has become possible with the successful development of a 122-channel whole-head MEG (magnetoencephalography) system for non-invasively measuring the magnetic field outside the human head (Lounasmaa et al., IBRO NEWS, 21(2), 1993). In the proposed study we will utilize this whole-head system to detect spontaneous MEG signals from the frontal lobe of healthy volunteers during an alert rest period, during a short-term memory task, and finally again during a rest period. The memory task will consist of a presentation of a set of items to be remembered (i.e. spatial positions of items in the visual field, tone of differing pitches or words presented either visually or auditorily), followed by a retention period, and finally by a test phase where old and new items will be presented to test recognition memory. The coherence of spontaneous MEG activity will be measured to detect activities in the frontal lobe during the rest and retention periods. Localized changes in the coherence pattern will indicate the involvement of the frontal lobe in short-term memory. Asymmetry of the coherence pattern across the hemispheres will be also examined. Temporal kinetics of cortical involvement will be inferred from temporal changes in the coherence pattern during the retention period. Unlikely in previous studies of coherence, we will also examine the source coherence by solving for the source covariance matrix from the MEG covariance maori and test for the source activities in the frontal region during a retention interval. This study may open a new area of application for MEG namely in measuring functions of the associative areas of both healthy people and patients with neurological diseases.