Neuronal correlates of sensory working memory in the auditory cortex of humans an monkeys

工作记忆（WM）是指用于临时存储信息的过程，是我们执行日常功能的基本先决条件。它涉及到包括感觉皮质在内的广泛的大脑区域网络。早期听觉皮层在听觉脑损伤中的作用也可能是由于听觉脑损伤的高准确性。在人类和非人类灵长类动物的趋同方法中，我们在目前的资助期内进行了一系列实验，要求在相同的刺激材料上执行不同的任务，两种声音的序列被延迟分开。当受试者执行任务时，记录了猴子的听觉和前额叶皮层以及人类的磁场的单单元和多单元活动和局部场电位。总的来说，这些实验的结果表明，听觉皮层在延迟期间的差异活动部分是由于真正的听觉WM，而不仅仅是其他不可避免地涉及这种范式并与记忆过程混合的认知过程，例如对第二刺激的预期，对运动反应替代的准备或对奖励的预期。在初步研究计划成功实现的基础上，我们现在建议对猴子和人类的数据进行建模，并通过新的实验（包括猴子的皮质内电刺激和人类的磁场记录）来测试模型产生的预测。我们将使用May及其同事的听觉皮层信息处理的计算模型。这个模型非常适合目前的目的，因为它可以同时模拟中观尺度上的神经活动和局部场电位，并在宏观水平上模拟磁场的产生。因此，它提供了颅内和颅外神经活动测量之间急需的联系。

Working memory (WM) refers to the processes used for temporarily storing information and is a fundamental prerequisite for our abilities to perform everyday functions. It involves a broad network of brain areas including sensory cortices. A role of early auditory cortex in auditory WM also appears likely because of the high accuracy of auditory WM. In a convergent approach with humans and non-human primates, we have conducted, in the current funding period, series of experiments requiring the performance of different tasks on the same stimulus material, sequences of two sounds separated by a delay. While subjects performed the tasks, single- and multiunit activity and local field potentials were recorded in monkey auditory and prefrontal cortices and magnetic fields in humans. Collectively, the results of these experiments demonstrate that differential activity in auditory cortex during the delay is partly due to true auditory WM and not only to other cognitive processes inevitably involved in such paradigms and intermingled with the memory process, such as anticipation of the second stimulus, preparation for motor response alternatives or expectation of a reward. Based on the successful realization of the initial research plan, we now propose to model the monkey and human data and to test, by means of new experiments (involving intracortical electrical stimulation in monkeys and magnetic field recordings in humans), predictions generated by the model. We will use the computational model of information processing in auditory cortex by May and colleagues. This model is ideally suited for the present purpose because it allows to simultaneously simulate neural activity and local field potentials on a mesoscopic scale and the generation of magnetic fields on a macroscopic level. It therefore provides a much-needed link between intra- and extracranial neural activity measures.