Laboratorium voor Neuro- en Psychofysiologie, K.U. Leuven Medical School, B-3000 Leuven, Belgium.
Cereb Cortex. 2012 Apr;22(4):838-53. doi: 10.1093/cercor/bhr150. Epub 2011 Jun 27.
Lesion studies in monkeys have suggested a modest left hemisphere dominance for processing species-specific vocalizations, the neural basis of which has thus far remained unclear. We used contrast agent-enhanced functional magnetic resonance imaging to map the regions of the rhesus monkey brain involved in processing conspecific vocalizations as well as human speech and emotional sounds. Control conditions included scrambled versions of all 3 stimuli and silence. Compared with silence, all stimuli activated widespread parts of the auditory cortex and subcortical auditory structures with a right hemispheric bias at the level of the auditory core. However, comparing intact with scrambled sounds revealed a leftward bias in the auditory belt and the parabelt. The left-sided dominance was stronger and more robust for human speech than for rhesus vocalizations and hence does not reflect conspecific call selectivity but rather the processing of complex spectrotemporal patterns, such as those present in human speech and in some of the rhesus monkey vocalizations. This was confirmed by regressing brain activity with a model-derived parameter indexing the prevalence of such patterns. Our results indicate that processing of vocal sounds in the lateral belt and parabelt is asymmetric in monkeys, as predicted from lesion studies.
猴子的损伤研究表明，大脑的左半球在处理物种特异性声音方面具有一定的优势，但迄今为止，其神经基础仍不清楚。我们使用对比剂增强功能磁共振成像来绘制猕猴大脑中参与处理同种声音以及人类语音和情感声音的区域。对照条件包括所有 3 种刺激物的乱序版本和静音。与静音相比，所有刺激物都激活了听觉皮层和皮质下听觉结构的广泛区域，在听觉核心区域存在右半球偏向。然而，将完整声音与乱序声音进行比较，发现听觉带和副听觉带呈左侧偏向。与猕猴叫声相比，人类语音的左侧优势更强且更稳健，因此它并不反映同种呼叫选择性，而是反映复杂的时频谱模式的处理，如人类语音和某些猕猴叫声中存在的模式。通过使用模型衍生的参数回归大脑活动来证实这一点，该参数指数征了这种模式的出现频率。我们的结果表明，猴子的外侧带和副听觉带中的声音处理是不对称的，这与损伤研究的预测一致。
