Kumar Sukhbinder, Joseph Sabine, Gander Phillip E, Barascud Nicolas, Halpern Andrea R, Griffiths Timothy D
Auditory Group, Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom, Wellcome Trust Centre for Neuroimaging, London WC1N 3BG, United Kingdom,
Institute of Cognitive Neuroscience, London, United Kingdom, Institute of Neurology, UCL Neuroscience, London WC1N 3AR, United Kingdom.
J Neurosci. 2016 Apr 20;36(16):4492-505. doi: 10.1523/JNEUROSCI.4341-14.2016.
The brain basis for auditory working memory, the process of actively maintaining sounds in memory over short periods of time, is controversial. Using functional magnetic resonance imaging in human participants, we demonstrate that the maintenance of single tones in memory is associated with activation in auditory cortex. In addition, sustained activation was observed in hippocampus and inferior frontal gyrus. Multivoxel pattern analysis showed that patterns of activity in auditory cortex and left inferior frontal gyrus distinguished the tone that was maintained in memory. Functional connectivity during maintenance was demonstrated between auditory cortex and both the hippocampus and inferior frontal cortex. The data support a system for auditory working memory based on the maintenance of sound-specific representations in auditory cortex by projections from higher-order areas, including the hippocampus and frontal cortex.
In this work, we demonstrate a system for maintaining sound in working memory based on activity in auditory cortex, hippocampus, and frontal cortex, and functional connectivity among them. Specifically, our work makes three advances from the previous work. First, we robustly demonstrate hippocampal involvement in all phases of auditory working memory (encoding, maintenance, and retrieval): the role of hippocampus in working memory is controversial. Second, using a pattern classification technique, we show that activity in the auditory cortex and inferior frontal gyrus is specific to the maintained tones in working memory. Third, we show long-range connectivity of auditory cortex to hippocampus and frontal cortex, which may be responsible for keeping such representations active during working memory maintenance.
听觉工作记忆是在短时间内积极维持声音在记忆中的过程，其大脑基础存在争议。我们在人类受试者中使用功能磁共振成像技术，证明了记忆中单一音调的维持与听觉皮层的激活有关。此外，在海马体和额下回中观察到持续激活。多体素模式分析表明，听觉皮层和左侧额下回的活动模式能够区分记忆中维持的音调。在维持过程中，听觉皮层与海马体和额下回之间均表现出功能连接。这些数据支持了一种基于高阶区域（包括海马体和额叶皮层）投射在听觉皮层中维持声音特异性表征的听觉工作记忆系统。
在这项研究中，我们证明了一个基于听觉皮层、海马体和额叶皮层的活动以及它们之间功能连接的工作记忆中声音维持系统。具体而言，我们的研究在先前工作的基础上取得了三个进展。第一，我们有力地证明了海马体参与听觉工作记忆的所有阶段（编码、维持和检索）：海马体在工作记忆中的作用存在争议。第二，使用模式分类技术，我们表明听觉皮层和额下回的活动对于工作记忆中维持的音调具有特异性。第三，我们展示了听觉皮层与海马体和额叶皮层之间的长程连接，这可能是在工作记忆维持期间保持此类表征活跃的原因。
