Horner A J, Henson R N
MRC Cognition & Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 7EF, UK.
Neuropsychologia. 2008;46(7):1979-91. doi: 10.1016/j.neuropsychologia.2008.01.018. Epub 2008 Feb 2.
Prior exposure to a stimulus can facilitate its subsequent identification and classification, a phenomenon called priming. This behavioural facilitation is usually accompanied by a reduction in neural response within specific cortical regions (repetition suppression, RS). Recent research has suggested that both behavioural priming and RS can be largely determined by previously learned stimulus-response associations. According to this view, a direct association forms between the stimulus presented and the response made to it. On a subsequent encounter with the stimulus, this association automatically cues the response, bypassing the various processing stages that were required to select that response during its first presentation. Here we reproduce behavioural evidence for such stimulus-response associations, and show the PFC to be sensitive to such changes. In contrast, RS within ventral temporal regions (such as the fusiform cortex), which are usually associated with perceptual processing, is shown to be robust to response changes. The present study therefore suggests a dissociation between RS within the PFC, which may be sensitive to retrieval of stimulus-response associations, and RS within posterior perceptual regions, which may reflect facilitation of perceptual processing independent of stimulus-response associations.
先前接触过某种刺激可以促进随后对该刺激的识别和分类，这一现象称为启动效应。这种行为促进通常伴随着特定皮层区域内神经反应的减少（重复抑制，RS）。最近的研究表明，行为启动效应和重复抑制很大程度上都可能由先前习得的刺激-反应关联所决定。根据这一观点，呈现的刺激与对其做出的反应之间会形成直接关联。在随后再次遇到该刺激时，这种关联会自动提示反应，绕过了在首次呈现该反应时选择该反应所需的各种处理阶段。在这里，我们重现了此类刺激-反应关联的行为证据，并表明前额叶皮层对此类变化敏感。相比之下，腹侧颞叶区域（如梭状回）内的重复抑制，通常与知觉加工相关，已被证明对反应变化具有较强的抗性。因此，本研究表明，前额叶皮层内的重复抑制可能对刺激-反应关联的提取敏感，而后侧知觉区域内的重复抑制可能反映了独立于刺激-反应关联的知觉加工促进，二者存在分离。
