Furl Nicholas
MRC Cognition and Brain Sciences Unit Cambridge, UK ; Department of Psychology, Royal Holloway, University of London Egham, UK.
Front Hum Neurosci. 2015 May 7;9:253. doi: 10.3389/fnhum.2015.00253. eCollection 2015.
Visual category perception is thought to depend on brain areas that respond specifically when certain categories are viewed. These category-sensitive areas are often assumed to be "modules" (with some degree of processing autonomy) and to act predominantly on feedforward visual input. This modular view can be complemented by a view that treats brain areas as elements within more complex networks and as influenced by network properties. This network-oriented viewpoint is emerging from studies using either diffusion tensor imaging to map structural connections or effective connectivity analyses to measure how their functional responses influence each other. This literature motivates several hypotheses that predict category-sensitive activity based on network properties. Large, long-range fiber bundles such as inferior fronto-occipital, arcuate and inferior longitudinal fasciculi are associated with behavioral recognition and could play crucial roles in conveying backward influences on visual cortex from anterior temporal and frontal areas. Such backward influences could support top-down functions such as visual search and emotion-based visual modulation. Within visual cortex itself, areas sensitive to different categories appear well-connected (e.g., face areas connect to object- and motion sensitive areas) and their responses can be predicted by backward modulation. Evidence supporting these propositions remains incomplete and underscores the need for better integration of DTI and functional imaging.
视觉类别感知被认为依赖于在查看特定类别时会特异性做出反应的脑区。这些类别敏感区域通常被假定为“模块”（具有一定程度的处理自主性），并且主要作用于前馈视觉输入。这种模块化观点可以通过另一种观点来补充，即把脑区视为更复杂网络中的元素，并受网络特性的影响。这种以网络为导向的观点正从使用扩散张量成像来绘制结构连接或有效连接分析来测量其功能反应如何相互影响的研究中逐渐显现。这些文献催生了几个基于网络特性预测类别敏感活动的假说。诸如额枕下束、弓状束和下纵束等大型远程纤维束与行为识别相关，并且在从前颞叶和额叶区域向视觉皮层传递反向影响方面可能发挥关键作用。这种反向影响可以支持诸如视觉搜索和基于情感的视觉调节等自上而下的功能。在视觉皮层本身内部，对不同类别敏感的区域似乎连接良好（例如，面部区域与物体和运动敏感区域相连），并且它们的反应可以通过反向调节来预测。支持这些观点的证据仍然不完整，这突出了更好地整合扩散张量成像和功能成像的必要性。
