Institute of Computer Science, University of Bern, Bern 3012, Switzerland.
Center for Experimental Neurology, Sleep Wake Epilepsy Center, NeuroTec, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern 3010, Switzerland.
J Neurosci. 2023 May 17;43(20):3696-3707. doi: 10.1523/JNEUROSCI.1941-22.2023. Epub 2023 Apr 12.
During rest, intrinsic neural dynamics manifest at multiple timescales, which progressively increase along visual and somatosensory hierarchies. Theoretically, intrinsic timescales are thought to facilitate processing of external stimuli at multiple stages. However, direct links between timescales at rest and sensory processing, as well as translation to the auditory system are lacking. Here, we measured intracranial EEG in 11 human patients with epilepsy (4 women), while listening to pure tones. We show that, in the auditory network, intrinsic neural timescales progressively increase, while the spectral exponent flattens, from temporal to entorhinal cortex, hippocampus, and amygdala. Within the neocortex, intrinsic timescales exhibit spatial gradients that follow the temporal lobe anatomy. Crucially, intrinsic timescales at baseline can explain the latency of auditory responses: as intrinsic timescales increase, so do the single-electrode response onset and peak latencies. Our results suggest that the human auditory network exhibits a repertoire of intrinsic neural dynamics, which manifest in cortical gradients with millimeter resolution and may provide a variety of temporal windows to support auditory processing. Endogenous neural dynamics are often characterized by their intrinsic timescales. These are thought to facilitate processing of external stimuli. However, a direct link between intrinsic timing at rest and sensory processing is missing. Here, with intracranial EEG, we show that intrinsic timescales progressively increase from temporal to entorhinal cortex, hippocampus, and amygdala. Intrinsic timescales at baseline can explain the variability in the timing of intracranial EEG responses to sounds: cortical electrodes with fast timescales also show fast- and short-lasting responses to auditory stimuli, which progressively increase in the hippocampus and amygdala. Our results suggest that a hierarchy of neural dynamics in the temporal lobe manifests across cortical and limbic structures and can explain the temporal richness of auditory responses.
在休息时，内在神经动力学表现出多个时间尺度，这些时间尺度沿着视觉和体感层次结构逐渐增加。从理论上讲，内在时间尺度被认为有助于在多个阶段处理外部刺激。然而，静息时的时间尺度与感觉处理之间以及与听觉系统之间的直接联系尚不清楚。在这里，我们在 11 名患有癫痫的人类患者（4 名女性）中测量了颅内 EEG，同时聆听纯音。我们表明，在听觉网络中，内在神经时间尺度从颞叶到内嗅皮层、海马体和杏仁核逐渐增加，而频谱指数则趋于平坦。在内皮层中，内在时间尺度表现出遵循颞叶解剖结构的空间梯度。至关重要的是，基线时的内在时间尺度可以解释听觉反应的潜伏期：随着内在时间尺度的增加，单个电极的反应起始和峰值潜伏期也会增加。我们的结果表明，人类听觉网络表现出一系列内在神经动力学，这些动力学以毫米级分辨率表现为皮质梯度，并可能提供多种时间窗口来支持听觉处理。内源性神经动力学通常以其内在时间尺度为特征。这些被认为有助于处理外部刺激。然而，静息时的内在定时与感觉处理之间的直接联系尚不清楚。在这里，我们使用颅内 EEG 表明，内在时间尺度从颞叶到内嗅皮层、海马体和杏仁核逐渐增加。基线时的内在时间尺度可以解释颅内 EEG 对声音反应的时间变异性：具有快速时间尺度的皮质电极也对听觉刺激表现出快速和短暂的反应，这些反应在海马体和杏仁核中逐渐增加。我们的结果表明，颞叶中的神经动力学层次结构在皮质和边缘结构中表现出来，并可以解释听觉反应的时间丰富性。
