Alegre M, Alvarez-Gerriko I, Valencia M, Iriarte J, Artieda J
Neurophysiology Laboratory, Neuroscience Area, CIMA, Universidad de Navarra, Pamplona, Spain.
Clin Neurophysiol. 2008 Feb;119(2):290-300. doi: 10.1016/j.clinph.2007.10.017.
Stimulus-induced movements are accompanied by a definite pattern of oscillatory changes, that include a frontal 15 Hz synchronization, a central peri-movement desynchronization, and a contralateral beta rebound after the movement. Our aim was to study the oscillatory changes related to the forced termination of a single complex motor program (signature) and compare them with those observed after the normal termination of the movement.
Fifty-eight reference-free EEG channels were analyzed in 10 healthy subjects. A 2000 Hz tone (S1, go signal) indicated the subject to begin to write his/her complete signature. A second 2000 Hz tone 0.8 s afterwards (50% probability: S2, stop signal) indicated the subject to stop immediately. Movement-related energy changes were evaluated by means of time-frequency (Gabor) transforms.
A frontal 15 Hz synchronization was observed after S1, but not after S2. The amplitude of the post-movement beta increase was significantly lower when the movement was abnormally terminated (p=0.005), while the peri-movement decrease was similar.
The forced termination of a motor program reduces significantly the amplitude of the post-movement beta increment, conserving its temporal pattern. Also, the presence of the 15 Hz frontal synchronization only after S1, together with the results of previous studies, suggests that the frontal mechanisms involved in go/no go and stop signals are very different.
Our results indicate that the beta rebound is an active process, independent of the peri-movement beta decrease, which is influenced by how the movement is terminated.
刺激诱发的运动伴随着特定模式的振荡变化，包括额叶15赫兹同步化、中央运动周围去同步化以及运动后对侧β波反弹。我们的目的是研究与单个复杂运动程序（签名）的强制终止相关的振荡变化，并将其与运动正常终止后观察到的变化进行比较。
对10名健康受试者的58个无参考脑电图通道进行分析。2000赫兹的音调（S1，启动信号）指示受试者开始书写其完整签名。0.8秒后第二个2000赫兹的音调（50%概率：S2，停止信号）指示受试者立即停止。通过时频（加博尔）变换评估与运动相关的能量变化。
在S1后观察到额叶15赫兹同步化，但在S2后未观察到。当运动异常终止时，运动后β波增加的幅度显著降低（p = 0.005），而运动周围的降低相似。
运动程序的强制终止显著降低了运动后β波增量的幅度，同时保留了其时间模式。此外，仅在S1后出现的15赫兹额叶同步化以及先前研究的结果表明，参与启动/停止信号的额叶机制非常不同。
我们的结果表明，β波反弹是一个活跃的过程，独立于运动周围的β波降低，而运动周围的β波降低受运动终止方式的影响。
