Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Neurosci. 2012 May 2;32(18):6177-82. doi: 10.1523/JNEUROSCI.5153-11.2012.
The temporal context of an acoustic signal can greatly influence its perception. The present study investigated the neural correlates underlying perceptual facilitation by regular temporal contexts in humans. Participants listened to temporally regular (periodic) or temporally irregular (nonperiodic) sequences of tones while performing an intensity discrimination task. Participants performed significantly better on intensity discrimination during periodic than nonperiodic tone sequences. There was greater activation in the putamen for periodic than nonperiodic sequences. Conversely, there was greater activation in bilateral primary and secondary auditory cortices (planum polare and planum temporale) for nonperiodic than periodic sequences. Across individuals, greater putamen activation correlated with lesser auditory cortical activation in both right and left hemispheres. These findings suggest that temporal regularity is detected in the putamen, and that such detection facilitates temporal-lobe cortical processing associated with superior auditory perception. Thus, this study reveals a corticostriatal system associated with contextual facilitation for auditory perception through temporal regularity processing.
声音信号的时间背景会极大地影响其感知。本研究旨在探讨人类对有规则时间背景的感知促进的神经关联。参与者在执行强度辨别任务时，聆听有规则（周期性）或无规则（非周期性）的音序。参与者在周期性而非非周期性的音序中表现出更好的强度辨别能力。与非周期性音序相比，参与者在周期性音序时纹状体的激活程度更大。相反，与周期性音序相比，双侧初级和次级听觉皮层（极区和颞区）在非周期性音序时的激活程度更大。在个体之间，纹状体的激活程度与右半球和左半球听觉皮层的激活程度呈负相关。这些发现表明，时间规律性在纹状体中被检测到，这种检测促进了与卓越听觉感知相关的颞叶皮层处理。因此，本研究揭示了一个与通过时间规律性处理促进听觉感知的皮质纹状体系统。
