De Pascalis V, Ray W J
Department of Psychology, University of Rome La Sapienza, Italy.
Int J Psychophysiol. 1998 May;28(3):301-15. doi: 10.1016/s0167-8760(97)00083-4.
The present study describes a phasic event-related synchronization (ERS) in the gamma band (36-44 Hz) induced by the onset of probe visual stimuli. The experiment consisted of two experimental tasks with high and low memory-load in which a geometrical figure (S1) was held in memory for comparison with a subsequent stimulus (S2). In each task a Go-NoGo paradigm was used with a Same-Different discrimination task. The aim of the study was to examine the influence on 40-Hz ERS of stimulus type ('Same-Different') and of response (Go-NoGo) task as moderated by activation or effort level (high/low memory-load). The investigation was carried out in 27 women. The EEG was recorded from FP1, FP2, F3, F4, P3, P4, O1 and O2 scalp sites referenced to linked earlobes. As a manipulation check for activation level, we recorded heart rate (HR) during the S1-S2 period. A main peak of activity was found around 160 ms with a maximum at occipital sites. The amplitude of this peak was higher in the high memory-load as compared to the low memory-load condition. This difference was manifested mainly at F3 and O2 scalp sites. A larger 40-Hz peak at F3 was also found in the Go compared to the NoGo condition. No 40-Hz ERS differences between Same and Different trials were observed. The HR was found sensitive to the stimulus type showing a greater HR deceleration response to S2 for Same trials, as compared to Different ones. In parallel with 40-Hz ERS response, the HR deceleration was more pronounced for the high memory-load as compared to the low memory-load condition. The results indicate that the 40-Hz ERS is dependent upon both memory-load and motor responding. The influence of memory load on cognitive (Same-Different) and motor response (Go-NoGo) variables is discussed.
本研究描述了由探测视觉刺激的开始所诱发的γ波段（36 - 44赫兹）的阶段性事件相关同步化（ERS）。实验包括两个具有高记忆负荷和低记忆负荷的实验任务，其中一个几何图形（S1）被记忆下来以便与随后的刺激（S2）进行比较。在每个任务中，使用了一个“是-否”范式以及一个“相同-不同”辨别任务。该研究的目的是考察刺激类型（“相同-不同”）和反应（“是-否”）任务对40赫兹ERS的影响，这种影响受激活或努力水平（高/低记忆负荷）的调节。该调查在27名女性中进行。脑电图记录于FP1、FP2、F3、F4、P3、P4、O1和O2头皮部位，参考连接耳垂。作为对激活水平的操作检查，我们在S1 - S2期间记录了心率（HR）。在约160毫秒处发现一个主要的活动峰值，在枕部部位达到最大值。与低记忆负荷条件相比，该峰值的幅度在高记忆负荷时更高。这种差异主要表现在F3和O2头皮部位。与“否”条件相比，在“是”条件下F3处还发现了更大的40赫兹峰值。在“相同”和“不同”试验之间未观察到40赫兹ERS的差异。发现心率对刺激类型敏感，与“不同”试验相比，“相同”试验中对S2的心率减速反应更大。与40赫兹ERS反应并行，与低记忆负荷条件相比，高记忆负荷时心率减速更明显。结果表明，40赫兹ERS既依赖于记忆负荷，也依赖于运动反应。讨论了记忆负荷对认知（“相同-不同”）和运动反应（“是-否”）变量的影响。
