Leiberg Susanne, Lutzenberger Werner, Kaiser Jochen
Department of Psychiatry and Psychotherapy, RWTH Aachen University, Germany.
Brain Res. 2006 Nov 20;1120(1):131-40. doi: 10.1016/j.brainres.2006.08.066. Epub 2006 Sep 20.
The present magnetoencephalography study investigated memory load-dependent changes in cortical oscillatory activity during a modified auditory version of the Sternberg paradigm. Twelve subjects were presented with test stimulus sets of 1-3 syllables spoken in a natural female voice. After an 800-ms delay period, a probe syllable was presented and subjects had to judge whether the probe had been included in the preceding test set. Compared to a non-memory-control task, memory trials elicited an increase of beta activity over right temporal regions and an increase of alpha activity over right middle prefrontal cortex at the end of the delay phase. Monotonic increases in spectral amplitude as a function of memory load were revealed for the beta band over right temporal sensors and the alpha band over right frontal sensors during the delay period. The results demonstrate the relevance of both beta and alpha oscillations for the memorization of multiple stimuli. The former may be associated with the representation of task-relevant stimulus features, while the latter may reflect the top-down control of these representations.
本脑磁图研究在经过修改的听觉版斯特恩伯格范式中，调查了与记忆负荷相关的皮质振荡活动变化。向12名受试者呈现由自然女性声音说出的1至3个音节的测试刺激集。在800毫秒的延迟期后，呈现一个探测音节，受试者必须判断该探测音节是否包含在之前的测试集中。与非记忆控制任务相比，记忆试验在延迟阶段结束时，右侧颞区的β活动增加，右侧额中回皮质的α活动增加。在延迟期，右侧颞部传感器上方的β频段和右侧额叶传感器上方的α频段显示出频谱幅度随记忆负荷单调增加。结果表明，β和α振荡对于多个刺激的记忆都具有相关性。前者可能与任务相关刺激特征的表征有关，而后者可能反映了对这些表征的自上而下的控制。
