Grotheer Mareike, Kovács Gyula
Department of Cognitive Neuroscience, Institute of Psychology, Friedrich Schiller University Jena, 07743 Jena, Germany; DFG Research Unit Person Perception, Friedrich Schiller University Jena, 07743 Jena, Germany.
Department of Cognitive Neuroscience, Institute of Psychology, Friedrich Schiller University Jena, 07743 Jena, Germany; DFG Research Unit Person Perception, Friedrich Schiller University Jena, 07743 Jena, Germany; Department of Cognitive Science, Budapest University of Technology and Economics, 1111 Budapest, Hungary.
Neuropsychologia. 2015 Jan;67:175-82. doi: 10.1016/j.neuropsychologia.2014.12.017. Epub 2014 Dec 17.
Several neuroimaging studies showed that fulfilled expectations increase the magnitude of repetition suppression (RS) in the face-selective visual cortex. However, previous fMRI studies did not allow a distinction between the reductions of the response due to stimulus repetitions and fulfilled expectations (expectation suppression, ES). In most prior studies repetitions and expectations were not independent from each other as repetitions occurred more often when they were expected and less often when they were not expected, thereby confounding RS with ES. To overcome this confound, we presented pairs of female and male faces that were either repeating or alternating with an overall probability of 50-50%. Orthogonally to this, the gender of the first face in each pair signaled with 75% accuracy whether repetitions or alternations were more likely to occur. We found significant RS in the FFA, the OFA and the LO. In addition, these areas showed a reduction of the response for expected when compared to surprising trials. Moreover, the effects of RS and ES were always additive rather than interactive in our ROIs. This implies that stimulus repetition and fulfilled expectations can be dissociated from one another in terms of their effects on the neural responses.
多项神经影像学研究表明，预期实现会增强面孔选择性视觉皮层中重复抑制（RS）的程度。然而，以往的功能磁共振成像（fMRI）研究无法区分由于刺激重复和预期实现（预期抑制，ES）导致的反应降低。在大多数先前的研究中，重复和预期并非相互独立，因为当预期重复时，重复出现的频率更高，而当未预期重复时，重复出现的频率更低，从而使RS与ES混淆。为了克服这种混淆，我们呈现了成对的女性和男性面孔，它们以50%对50%的总体概率重复或交替出现。与此正交的是，每对中的第一张面孔的性别以75%的准确率表明重复或交替出现的可能性更大。我们在梭状回面孔区（FFA）、枕颞叶面孔区（OFA）和外侧枕叶（LO）发现了显著的RS。此外，与令人惊讶的试验相比，这些区域在预期试验中反应降低。此外，在我们的感兴趣区域（ROIs）中，RS和ES的效应总是相加的，而不是相互作用的。这意味着刺激重复和预期实现在对神经反应的影响方面可以彼此分离。
