Mazza Veronica, Turatto Massimo, Caramazza Alfonso
Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy.
Cortex. 2009 Jul-Aug;45(7):879-90. doi: 10.1016/j.cortex.2008.10.009. Epub 2008 Nov 14.
N2pc is generally interpreted as the electrocortical correlate of the distractor-suppression mechanisms through which attention selection takes place in humans. Here, we present data that challenge this common N2pc interpretation. In Experiment 1, multiple distractors induced greater N2pc amplitudes even when they facilitated target identification, despite the suppression account of the N2pc predicted the contrary; in Experiment 2, spatial proximity between target and distractors did not affect the N2pc amplitude, despite resulting in more interference in response times; in Experiment 3, heterogeneous distractors delayed response times but did not elicit a greater N2pc relative to homogeneous distractors again in contrast with what would have predicted the suppression hypothesis. These results do not support the notion that the N2pc unequivocally mirrors distractor-suppression processes. We propose that the N2pc indexes mechanisms involved in identifying and localizing relevant stimuli in the scene through enhancement of their features and not suppression of distractors.
N2pc通常被解释为人类注意力选择过程中干扰抑制机制的电皮层相关指标。在此，我们展示了一些数据，这些数据对这种常见的N2pc解释提出了挑战。在实验1中，即使多个干扰项有助于目标识别，它们仍会诱发更大的N2pc波幅，尽管N2pc的抑制理论预测的结果相反；在实验2中，目标与干扰项之间的空间距离并未影响N2pc波幅，尽管这会导致反应时间受到更多干扰；在实验3中，异质性干扰项会延迟反应时间，但相对于同质性干扰项，它们并未引发更大的N2pc波幅，这再次与抑制假说的预测结果相反。这些结果并不支持N2pc明确反映干扰抑制过程的观点。我们提出，N2pc指标所涉及的机制是通过增强相关刺激的特征来识别和定位场景中的相关刺激，而不是抑制干扰项。
