No abstract

No abstract

A simple procedure for analyzing multi‐subject functional magnetic resonance imaging (fMRI) data is proposed. In the first step, a voxel‐wise t‐test across standardized z‐maps is performed to identify areas that are consistently activated across subjects. In the second step, for each area, individual mean z‐scores are calculated and subsequently subjected to an analysis of variance. An example is provided. J. Magn. Reson. Imaging 2000;11:61–64. © 2000 Wiley‐Liss, Inc.

No abstract

We examined whether early visual processing reflects perceptual properties of a stimulus in addition to physical features. We recorded event-related potentials (ERPs) of 13 subjects in a visual classification task. We used four different stimuli which were all composed of four identical elements. One of the stimuli constituted an illusory Kanizsa square, another was composed of the same number of collinear line segments but the elements did not form a Gestalt. In addition, a target and a control stimulus were used which were arranged differently. These stimuli allow us to differentiate the processing of colinear line elements (stimulus features) and illusory figures (perceptual properties). The visual N170 in response to the illusory figure was significantly larger as compared to the other collinear stimulus. This is taken to indicate that the visual N170 reflects cognitive processes of Gestalt perception in addition to attentional processes and physical stimulus properties.