Assaneo M F, Rimmele J M, Orpella J, Ripollés P, de Diego-Balaguer R, Poeppel D
Department of Psychology, New York University, New York, NY, United States.
Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Frankfurt, Germany.
Front Integr Neurosci. 2019 Jul 17;13:28. doi: 10.3389/fnint.2019.00028. eCollection 2019.
The lateralization of neuronal processing underpinning hearing, speech, language, and music is widely studied, vigorously debated, and still not understood in a satisfactory manner. One set of hypotheses focuses on the temporal structure of perceptual experience and links auditory cortex asymmetries to underlying differences in neural populations with differential temporal sensitivity (e.g., ideas advanced by Zatorre et al. (2002) and Poeppel (2003). The Asymmetric Sampling in Time theory (AST) (Poeppel, 2003), builds on cytoarchitectonic differences between auditory cortices and predicts that modulation frequencies within the range of, roughly, the syllable rate, are more accurately tracked by the right hemisphere. To date, this conjecture is reasonably well supported, since - while there is some heterogeneity in the reported findings - the predicted asymmetrical entrainment has been observed in various experimental protocols. Here, we show that under specific processing demands, the rightward dominance disappears. We propose an enriched and modified version of the asymmetric sampling hypothesis in the context of speech. Recent work (Rimmele et al., 2018b) proposes two different mechanisms to underlie the auditory tracking of the speech envelope: one derived from the intrinsic oscillatory properties of auditory regions; the other induced by top-down signals coming from other non-auditory regions of the brain. We propose that under non-speech listening conditions, the intrinsic auditory mechanism dominates and thus, in line with AST, entrainment is rightward lateralized, as is widely observed. However, (i) depending on individual brain structural/functional differences, and/or (ii) in the context of specific conditions, the relative weight of the top-down mechanism can increase. In this scenario, the typically observed auditory sampling asymmetry (and its rightward dominance) diminishes or vanishes.
支撑听力、言语、语言和音乐的神经元加工的偏侧化现象得到了广泛研究，引发了激烈争论，目前仍未得到令人满意的理解。一组假设聚焦于感知体验的时间结构，并将听觉皮层的不对称性与具有不同时间敏感性的神经群体的潜在差异联系起来（例如，扎托雷等人（2002年）和波佩尔（2003年）提出的观点）。时间不对称采样理论（AST）（波佩尔，2003年）基于听觉皮层之间的细胞结构差异构建，并预测大致在音节速率范围内的调制频率能被右半球更精确地追踪。迄今为止，这一推测得到了相当有力的支持，因为——尽管报告的研究结果存在一些异质性——在各种实验方案中都观察到了预测的不对称夹带现象。在此，我们表明在特定的加工需求下，右半球优势消失。我们在言语情境中提出了一个丰富且经过修正的不对称采样假设版本。最近的研究（里姆勒等人，2018b）提出了两种不同的机制来支撑语音包络的听觉追踪：一种源于听觉区域的内在振荡特性；另一种由来自大脑其他非听觉区域的自上而下信号诱导产生。我们提出，在非言语聆听条件下，内在听觉机制占主导，因此，与AST一致，夹带现象在右半球偏侧化，这是广泛观察到的情况。然而，（i）取决于个体大脑结构/功能差异，和/或（ii）在特定条件下，自上而下机制的相对权重可能增加。在这种情况下，通常观察到的听觉采样不对称性（及其右半球优势）会减弱或消失。
