Institute of Research in Psychology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Cortex. 2013 Oct;49(9):2583-9. doi: 10.1016/j.cortex.2013.05.002. Epub 2013 Jun 14.
Face perception is highly lateralized to the right hemisphere (RH) in humans, as supported originally by observations of face recognition impairment (prosopagnosia) following brain damage. Divided visual field presentations, neuroimaging and event-related potential studies have supported this view. While the latter studies are typically performed in right-handers, the few reported cases of prosopagnosia with unilateral left damage were left-handers, suggesting that handedness may shift or qualify the lateralization of face perception. We tested this hypothesis by recording the whole set of face-sensitive areas in 11 left-handers, using a face-localizer paradigm in functional magnetic resonance imaging (fMRI) (faces, cars, and their phase-scrambled versions). All face-sensitive areas identified (superior temporal sulcus, inferior occipital cortex, anterior infero-temporal cortex, amygdala) were strongly right-lateralized in left-handers, this right lateralization bias being as large as in a population of right-handers (40) tested with the same paradigm (Rossion et al., 2012). The notable exception was the so-called 'Fusiform face area' (FFA), an area that was slightly left lateralized in the population of left-handers. Since the left FFA is localized closely to an area sensitive to word form in the human brain ('Visual Word Form Area' - VWFA), the enhanced left lateralization of the FFA in left-handers may be due to a decreased competition with the representation of words. The implications for the neural basis of face perception, aetiology of brain lateralization in general, and prosopagnosia are also discussed.
人类的面孔感知高度偏向于右半球（RH），最初的证据来自于大脑损伤后对面孔识别障碍（面孔失认症）的观察。分视视野呈现、神经影像学和事件相关电位研究都支持这一观点。虽然这些研究通常在右利手人群中进行，但少数报道的单侧左脑损伤的面孔失认症病例为左利手，这表明利手可能会改变或影响面孔感知的偏侧化。我们通过在功能性磁共振成像（fMRI）中使用面孔定位范式（面孔、汽车及其相位混淆版本），在 11 名左利手者中记录了整套面孔敏感区域，从而验证了这一假设。在左利手者中，所有识别出的面孔敏感区域（颞上沟、枕下外侧皮质、前下颞叶皮质、杏仁核）都强烈偏向右侧，这种右偏侧化偏向与用相同范式测试的右利手者群体（Rossion 等人，2012）一样大。值得注意的例外是所谓的“梭状回面孔区”（FFA），在左利手者群体中，该区域略偏向左侧。由于左 FFA 与人类大脑中对单词形式敏感的区域（“视觉单词形式区” - VWFA）紧密相邻，因此左利手者 FFA 的左偏侧化增强可能是由于与单词表示的竞争减少所致。这对面孔感知的神经基础、大脑偏侧化的一般病因以及面孔失认症的意义也进行了讨论。
