NeuroImage Nord, Department of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany.
Brain. 2010 Jun;133(Pt 6):1729-36. doi: 10.1093/brain/awq102. Epub 2010 May 7.
Emotional signals are of pivotal relevance in social interactions. Neuroimaging and lesion studies have established an important role of the amygdala for the processing of these signals. While the human amygdala receives input from all sensory modalities, it is the visual modality that is most important for emotional aspects in social interactions. Consequently, amygdala involvement in visual emotional processing has been unequivocally established, whereas its role in auditory emotional processing is less clear. To investigate amygdala involvement in auditory emotional processing, we used functional magnetic resonance imaging in sighted and connatally blind volunteers, the latter of which lack visual experience during development but have outstanding capabilities to process auditory signals, which are their dominant source of information in social interactions. First, we observed a performance advantage of the connatally blind in auditory discrimination tasks that was paralleled by occipital cortex activation, which was not present in the sighted. More importantly, the blind not only showed robust selective activation in the amygdala to fearful and angry compared to neutral voices but also showed stronger activation to those stimuli than sighted participants. Higher amygdala activity for fearful items was further associated with individual performance in the blind, indicating that amygdala activation in the blind is not only driven by blindness per se but also by inter-individual differences in auditory capabilities. Our results indicate that the responsivity of the amygdala to emotional signals develops even in the absence of visual emotional experience and serves the sensory modality which is the most reliable source of emotional information.
情绪信号在社交互动中具有至关重要的作用。神经影像学和损伤研究已经确定了杏仁核在处理这些信号中的重要作用。虽然人类杏仁核接收来自所有感觉模式的输入，但对于社交互动中的情绪方面，视觉模式最为重要。因此，杏仁核参与视觉情绪处理已得到明确证实，而其在听觉情绪处理中的作用则不太清楚。为了研究杏仁核在听觉情绪处理中的作用，我们使用功能磁共振成像技术对视力正常和先天性失明的志愿者进行了研究，后者在发育过程中缺乏视觉体验，但具有出色的处理听觉信号的能力，而听觉信号是他们在社交互动中主要的信息来源。首先，我们观察到先天性失明者在听觉辨别任务中的表现优势，这与枕叶皮层的激活相平行，而视力正常者则没有这种激活。更重要的是，与视力正常者相比，盲人不仅对恐惧和愤怒的声音表现出强烈的选择性激活，而且对这些刺激的激活程度也比视力正常者更强。对于恐惧的刺激物，杏仁核的活动与盲人的个体表现进一步相关，这表明盲人的杏仁核激活不仅是由失明本身驱动的，还与听觉能力的个体差异有关。我们的研究结果表明，即使在没有视觉情绪体验的情况下，杏仁核对情绪信号的反应能力也会发展，并服务于最可靠的情绪信息来源的感觉模式。
