Tabas Alejandro, Siebert Anita, Supek Selma, Pressnitzer Daniel, Balaguer-Ballester Emili, Rupp André
Faculty of Science and Technology, Bournemouth University, Bournemouth, England, United Kingdom.
Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Zürich, Switzerland.
PLoS One. 2016 Apr 20;11(4):e0153947. doi: 10.1371/journal.pone.0153947. eCollection 2016.
Communication sounds are typically asymmetric in time and human listeners are highly sensitive to this short-term temporal asymmetry. Nevertheless, causal neurophysiological correlates of auditory perceptual asymmetry remain largely elusive to our current analyses and models. Auditory modelling and animal electrophysiological recordings suggest that perceptual asymmetry results from the presence of multiple time scales of temporal integration, central to the auditory periphery. To test this hypothesis we recorded auditory evoked fields (AEF) elicited by asymmetric sounds in humans. We found a strong correlation between perceived tonal salience of ramped and damped sinusoids and the AEFs, as quantified by the amplitude of the N100m dynamics. The N100m amplitude increased with stimulus half-life time, showing a maximum difference between the ramped and damped stimulus for a modulation half-life time of 4 ms which is greatly reduced at 0.5 ms and 32 ms. This behaviour of the N100m closely parallels psychophysical data in a manner that: i) longer half-life times are associated with a stronger tonal percept, and ii) perceptual differences between damped and ramped are maximal at 4 ms half-life time. Interestingly, differences in evoked fields were significantly stronger in the right hemisphere, indicating some degree of hemispheric specialisation. Furthermore, the N100m magnitude was successfully explained by a pitch perception model using multiple scales of temporal integration of auditory nerve activity patterns. This striking correlation between AEFs, perception, and model predictions suggests that the physiological mechanisms involved in the processing of pitch evoked by temporal asymmetric sounds are reflected in the N100m.
交流声音在时间上通常是不对称的，人类听众对这种短期时间不对称高度敏感。然而，听觉感知不对称的因果神经生理相关性在我们目前的分析和模型中仍然很大程度上难以捉摸。听觉建模和动物电生理记录表明，感知不对称源于听觉外周的多个时间尺度的时间整合的存在。为了验证这一假设，我们记录了人类中由不对称声音诱发的听觉诱发电位（AEF）。我们发现，如通过N100m动态幅度量化的那样，斜坡和衰减正弦波的感知音调显著性与AEF之间存在很强的相关性。N100m幅度随刺激半衰期增加，在调制半衰期为4 ms时，斜坡和衰减刺激之间显示出最大差异，在0.5 ms和32 ms时差异大大减小。N100m的这种行为与心理物理学数据密切平行，表现为：i）较长的半衰期与更强的音调感知相关，ii）衰减和斜坡之间的感知差异在半衰期为4 ms时最大。有趣的是，诱发电位的差异在右半球明显更强，表明存在一定程度的半球特化。此外，使用听觉神经活动模式的多个时间尺度的音高感知模型成功地解释了N100m的大小。AEF、感知和模型预测之间的这种显著相关性表明，时间不对称声音诱发的音高处理中涉及的生理机制反映在N100m中。
