The Visual Word Form Area (VWFA) and the Fusiform Face Area (FFA) represent classical examples of functional lateralization. The known hypothesis that lateralization of the VWFA and FFA are related remains controversial. We hypothesized that lateralization is independent and might be associated with lateralized high-level top-down mechanisms. For the VWFA this could emerge from left-lateralized language regions. This driving force might modulate local reorganization/recycling of function. Using an fMRI recognition paradigm, we quantified lateralization and investigated effective connectivity to examine mechanisms associated with lateralization in these regions (n = 58). Laterality patterns were more pronounced for VWFA than for FFA. Granger Causality Analysis found top-down effects only for the VWFA (left-lateralized, stemming from Broca's area). FFA exerted top-down effects on low-level visual areas. These findings suggest that distinct mechanisms are associated with hemispheric lateralization in object recognition: left lateralized top-down for VWFA and only early visual top-down effects concerning the FFA.

中文翻译：

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不同的机制驱动了视觉词形和梭形面部区域中物体识别的半球侧化

视觉词形区域 (VWFA) 和梭形面部区域 (FFA) 代表了功能侧化的经典示例。VWFA 和 FFA 的侧化相关的已知假设仍然存在争议。我们假设侧化是独立的，并且可能与侧化的高级自上而下机制有关。对于 VWFA，这可能出现在左侧语言区域。这种驱动力可能会调节功能的局部重组/循环。使用 fMRI 识别范式，我们量化了侧化并研究了有效连接以检查与这些区域中的侧化相关的机制（n = 58）。VWFA 的侧向模式比 FFA 更明显。格兰杰因果分析发现自上而下的影响仅适用于 VWFA（左侧化，源自 Broca' s 区域）。FFA 对低级视觉区域施加自上而下的效果。这些发现表明，不同的机制与物体识别中的半球侧化有关：VWFA 自上而下左侧偏侧，FFA 仅早期视觉自上而下效应。