Henson R N, Mouchlianitis E
MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, England, UK.
Neuroimage. 2007 Apr 15;35(3):1317-29. doi: 10.1016/j.neuroimage.2007.01.019. Epub 2007 Jan 31.
The aim of this fMRI study was to investigate whether spatial attention to the initial and/or repeated presentation of a stimulus is necessary to observe repetition-related modulations of the neural responses evoked by that stimulus. During each trial, two stimuli were presented simultaneously, one left and one right of fixation. During each block, participants were instructed to attend covertly to stimuli in one of the two hemifields and respond whether each was a face or house, ignoring the contralateral stimulus. Regions that preferred one stimulus category over the other, such as the fusiform face area and parahippocampal place area, showed evidence of some processing of the ignored stimuli. However, a reduced response to repeated stimuli (repetition suppression) was only reliable for preferred stimuli when both their initial and repeated presentations were attended. This suggests that attention is necessary for both the acquisition and expression of the neural mechanisms that underlie repetition suppression, at least over the lags of 2-16 intervening trials used here.
这项功能磁共振成像(fMRI)研究的目的是调查对刺激的初始呈现和/或重复呈现的空间注意力,对于观察该刺激诱发的神经反应的重复相关调制是否必要。在每次试验中,同时呈现两个刺激,一个在注视点左侧,一个在注视点右侧。在每个组块中,参与者被指示 covertly 关注两个半视野之一中的刺激,并回答每个刺激是脸还是房子,忽略对侧刺激。比起另一类刺激更偏好某一类刺激的区域,如梭状面孔区和海马旁回位置区,显示出对被忽略刺激进行了一些加工的证据。然而,只有当偏好刺激的初始呈现和重复呈现都被关注时,对重复刺激的反应减弱(重复抑制)才对于偏好刺激是可靠的。这表明,至少在此处使用的2 - 16次间隔试验的时滞范围内,注意力对于重复抑制背后的神经机制的获得和表达都是必要的。