Cognitive Neuroimaging Laboratory, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
Soc Cogn Affect Neurosci. 2007 Sep;2(3):240-50. doi: 10.1093/scan/nsm020.
The two halves of the brain are believed to play different roles in emotional processing, but the specific contribution of each hemisphere continues to be debated. The right-hemisphere hypothesis suggests that the right cerebrum is dominant for processing all emotions regardless of affective valence, whereas the valence specific hypothesis posits that the left hemisphere is specialized for processing positive affect while the right hemisphere is specialized for negative affect. Here, healthy participants viewed two split visual-field facial affect perception tasks during functional magnetic resonance imaging, one presenting chimeric happy faces (i.e. half happy/half neutral) and the other presenting identical sad chimera (i.e. half sad/half neutral), each masked immediately by a neutral face. Results suggest that the posterior right hemisphere is generically activated during non-conscious emotional face perception regardless of affective valence, although greater activation is produced by negative facial cues. The posterior left hemisphere was generally less activated by emotional faces, but also appeared to recruit bilateral anterior brain regions in a valence-specific manner. Findings suggest simultaneous operation of aspects of both hypotheses, suggesting that these two rival theories may not actually be in opposition, but may instead reflect different facets of a complex distributed emotion processing system.
大脑的两个半球被认为在情绪处理中扮演着不同的角色，但每个半球的具体贡献仍在争论中。右半球假说认为，右大脑半球在处理所有情绪时都占主导地位，而不管情绪效价如何，而效价特异性假说则认为左半球专门处理积极情绪，而右半球专门处理消极情绪。在这里，健康参与者在功能磁共振成像期间观看了两个分裂的视觉场面部情感感知任务，一个呈现混合的快乐面孔（即一半快乐/一半中性），另一个呈现相同的悲伤混合体（即一半悲伤/一半中性），每个混合体立即被中性面孔掩盖。结果表明，在后右半球在非意识情感面孔感知中普遍被激活，而不管情绪效价如何，尽管负面面部提示会产生更大的激活。后左半球通常对情感面孔的激活程度较低，但也似乎以效价特异性的方式招募双侧前脑区域。研究结果表明，这两个假说的各个方面同时运作，这表明这两个相互竞争的理论实际上并非相互对立，而是可能反映了复杂分布式情感处理系统的不同方面。
