Evolutionary Elongation of the Time Window of Integration in Auditory Cortex: Macaque vs. Human Comparison of the Effects of Sound Duration on Auditory Evoked Potentials
Evolutionary Elongation of the Time Window of Integration in Auditory Cortex: Macaque vs. Human Comparison of the Effects of Sound Duration on Auditory Evoked Potentials
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DOI：
10.3389/fnins.2019.00630
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发表时间：
2019-06-24
影响因子：
4.3
通讯作者：
Nakada, Tsutomu
中科院分区：
文献类型：
--
作者：
Itoh, Kosuke;Nejime, Masafumi;Nakada, Tsutomu
听觉皮质随着时间的推移整合听觉信息，以获得声音事件的神经表征，声音事件的时间尺度对知觉产生关键影响。这项工作通过比较人类和猴子的头皮记录的皮质听觉诱发电位(CAEP)在刺激持续时间从100毫秒(或更长)缩短到2毫秒时如何降低幅度来研究整合时间尺度上的物种差异。在短时间尺度上处理声音的大脑皮层回路将继续产生大的CAEP来缩短声音，而那些被调节到较长时间尺度的皮层回路将产生减弱的反应。在CAEP中鉴定出四个峰，人的标记为P1、Ni、P2和N2，猴子的标记为MP1、mN1、MP2和MN2。在人类中，随着声音持续时间的缩短，Ni的幅度减小，这与前面描述的N1的时间积分窗口(>；50ms)一致。相比之下，猕猴的mn1不受声音持续时间的影响，即使是最短暂的声音也能明显地引起mn1。短暂的声音也会在猕猴体内引起显著的MN2，但不会引起人类的N2。至于较早的潜伏期，即使是最短的声音，P1(人类)和MPL(猕猴)也能以最大幅度诱发。这些发现表明人类听觉皮质处理后期阶段的时间尺度延长，N1/mN1和后来的CAEP成分反映了这一点。更长的整合时间尺度将允许神经表示以语音和音乐为特征的复杂听觉特征。
The auditory cortex integrates auditory information over time to obtain neural representations of sound events, the time scale of which critically affects perception. This work investigated the species differences in the time scale of integration by comparing humans and monkeys regarding how their scalp-recorded cortical auditory evoked potentials (CAEPs) decrease in amplitude as stimulus duration is shortened from 100 ms (or longer) to 2 ms. Cortical circuits tuned to processing sounds at short time scales would continue to produce large CAEPs to brief sounds whereas those tuned to longer time scales would produce diminished responses. Four peaks were identified in the CAEPs and labeled P1, Ni, P2, and N2 in humans and mP1, mN1, mP2, and mN2 in monkeys. In humans, the Ni diminished in amplitude as sound duration was decreased, consistent with the previously described temporal integration window of N1 (>50 ms). In macaques, by contrast, the mN1 was unaffected by sound duration, and it was clearly elicited by even the briefest sounds. Brief sounds also elicited significant mN2 in the macaque, but not the human N2. Regarding earlier latencies, both P1 (humans) and mPl (macaques) were elicited at their full amplitudes even by the briefest sounds. These findings suggest an elongation of the time scale of late stages of human auditory cortical processing, as reflected by N1 /mN1 and later CAEP components. Longer time scales of integration would allow neural representations of complex auditory features that characterize speech and music.