Chouinard Philippe A, Morrissey Brendan F, Köhler Stefan, Goodale Melvyn A
CIHR Group on Action and Perception, Department of Psychology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 5B8.
Neuroimage. 2008 May 15;41(1):130-44. doi: 10.1016/j.neuroimage.2008.02.011. Epub 2008 Mar 10.
Functional magnetic-resonance imaging was used to identify areas involved in naming objects and to examine which of these areas adapted to either physical or semantics features of objects. We presented successive pairs of objects that were either the same exemplar of an object, different exemplars of that object, or different objects. By controlling for differences in physical features between pairs of different exemplars and different objects, visual areas in the occipital-temporal cortex were subject to repetition suppression when the same exemplars of an object were repeated, but not when different exemplars of an object were repeated. This was true independent of whether or not participants named objects. Repetition suppression in visual areas appeared therefore bound to physical features. Nevertheless, repetition suppression for physical features was greater in left visual areas when objects were named, suggesting that naming, known to depend on mechanisms in the left hemisphere, may induce greater attentional modulation in the left than in the right visual areas. Taken together, we propose that the difference between our findings and those of earlier studies that report semantic influences can be explained by the failure of those studies to control for differences in the appearance of different exemplars. Left frontal areas showed repetition suppression when either the same or different exemplars of an object were repeated, but only when participants named objects. These results suggest that visual areas process information about physical features without semantic modulation by higher-order areas, and that left frontal areas process semantic features, but the engagement of these processes is task modulated.
功能磁共振成像被用于识别与物体命名相关的区域，并研究这些区域中哪些区域适应了物体的物理或语义特征。我们展示了连续的成对物体，这些物体要么是同一物体的相同示例、该物体的不同示例，要么是不同的物体。通过控制不同示例和不同物体之间的物理特征差异，当同一物体的相同示例被重复时，枕颞叶皮层中的视觉区域会受到重复抑制，但当同一物体的不同示例被重复时则不会。无论参与者是否对物体进行命名，情况都是如此。因此，视觉区域中的重复抑制似乎与物理特征相关。然而，当物体被命名时，左侧视觉区域对物理特征的重复抑制更强，这表明已知依赖于左半球机制的命名，可能在左侧比右侧视觉区域引起更大的注意力调制。综上所述，我们认为我们的研究结果与早期报告语义影响的研究结果之间的差异，可以通过那些研究未能控制不同示例外观差异来解释。当同一物体的相同或不同示例被重复时，左侧额叶区域会出现重复抑制，但仅在参与者对物体进行命名时才会出现。这些结果表明，视觉区域在没有高阶区域语义调制的情况下处理有关物理特征的信息，并且左侧额叶区域处理语义特征，但这些过程的参与受到任务调制。
