Clark V P, Maisog J M, Haxby J V
Section on Functional Brain Imaging, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1366, USA.
J Neurophysiol. 1998 Jun;79(6):3257-65. doi: 10.1152/jn.1998.79.6.3257.
A new functional magnetic resonance imaging (fMRI) method was used to investigate the functional neuroanatomy of face perception and memory. Whole-brain fMRI data were acquired while four types of stimuli were presented sequentially in an unpredictable pseudorandom order at a rate of 0.5 Hz. Stimulus types were a single repeated memorized target face, unrepeated novel faces, nonsense scrambled faces, and a blank screen. Random stimulus sequences were designed to generate a functional response to each stimulus type that was uncorrelated with responses to other stimuli. This allowed fMRI responses to each stimulus type to be examined separately using multiple regression. Signal increases were found for all stimuli in ventral posterior cortex. Responses to intact faces extended to more anterior locations of occipitotemporal cortex than did responses to scrambled faces, consistent with previous studies of face perception. Responses evoked by novel faces were in regions of ventral occipitotemporal cortex medial to regions in which significant responses were evoked by the target face. The repeated target face stimulus also evoked activity in widely distributed regions of frontal and parietal cortex. These results demonstrate that cortical hemodynamic responses to interleaved novel and repeated stimuli can be distinguished and measured using fMRI with appropriate stimulus sequences and data analysis methods. This method can now be used to examine the neural systems involved in cognitive tasks that were previously impossible to study using positron emission tomography or fMRI.
一种新的功能磁共振成像（fMRI）方法被用于研究面部感知和记忆的功能神经解剖学。在以0.5赫兹的频率以不可预测的伪随机顺序依次呈现四种类型的刺激时，采集全脑fMRI数据。刺激类型包括单个重复的记忆目标面孔、不重复的新面孔、无意义的打乱面孔和空白屏幕。随机刺激序列旨在产生对每种刺激类型的功能反应，该反应与对其他刺激的反应不相关。这使得可以使用多元回归分别检查对每种刺激类型的fMRI反应。在腹侧后皮质中发现所有刺激都有信号增强。与之前对面部感知的研究一致，对完整面孔的反应比打乱面孔的反应延伸到枕颞皮质更靠前的位置。新面孔诱发的反应出现在枕颞叶腹侧皮质区域，该区域位于目标面孔诱发显著反应的区域内侧。重复的目标面孔刺激还在额叶和顶叶皮质的广泛分布区域诱发了活动。这些结果表明，使用适当的刺激序列和数据分析方法，fMRI可以区分和测量对交错的新刺激和重复刺激的皮质血流动力学反应。这种方法现在可用于研究涉及认知任务的神经系统，而这些任务以前使用正电子发射断层扫描或fMRI是无法研究的。
