Ioannides A A, Taylor J G, Liu L C, Gross J, Müller-Gärtner H W
Institute of Medicine, Research Center Jülich, Jülich, D-52425, Germany.
Neuroimage. 1998 Aug;8(2):149-62. doi: 10.1006/nimg.1998.0353.
The real-time, single-trial activity in the human auditory cortex was extracted from magnetoencephalographic signals. A predictor of single-trial activity was defined as the sum of the average response and a mean-free base level computed over a range of base times. For simple stimuli the residual (predicted-actual) activity had a stimulus-independent oscillatory (10 Hz) component. This component was larger and more durable in trained subjects, reaching saturation only in the most trained of the five subjects studied (S1). Changes in variability and associated reduction of the absolute value and duration of the oscillations were evident in experiments with stimuli loaded with information, saliency, or task contingency. Repetition reintroduces stimulus-independent oscillations very slowly. For S1, after training, the stimulus-independent oscillations were reestablished in the auditory cortices to the level seen for simple stimuli, except for the time periods and in the hemisphere associated with the combination of task demands and stimulus processing.
人类听觉皮层的实时单试次活动是从脑磁图信号中提取的。单试次活动的预测指标被定义为平均反应与在一系列基础时间上计算出的无均值基线水平之和。对于简单刺激，残余（预测值 - 实际值）活动具有与刺激无关的振荡（10赫兹）成分。在经过训练的受试者中，该成分更大且更持久，在所研究的五名受试者（S1）中，只有训练程度最高的受试者达到饱和。在加载有信息、显著性或任务偶然性的刺激实验中，变异性的变化以及振荡绝对值和持续时间的相关减少是明显的。重复刺激后，与刺激无关的振荡恢复得非常缓慢。对于S1，训练后，除了与任务需求和刺激处理组合相关的时间段和半球外，听觉皮层中与刺激无关的振荡重新建立到了简单刺激时的水平。
