Black box analysis of the skin senses as a multiple communication channel.

The skin senses have been investigated as a multichannel parallel information system. In psychophysical experiments using two cold two warmth and two vibration stimuli the capability of these senses have been determined for transmitting independent parallel information. A black box model is used to describe interactions within the system between pairs of signals causing two different response components in a multiple response after multimodal activation.

Recognition of organs in CT-image sequences: a model guided approach.

A method is proposed for segmentation of organs in CT-image sequences. An important feature of the method is the use of search areas to guide the segmentation process. Time consuming, data-directed operations are restricted to these areas, instead of being applied to the whole image.

Afterimages: a collective term for percepts of different origin.

Exposure of the eye to a strong photoflash results in a so-called "afterimage", which may last for 20 min or longer. In contrast, the true afterimage, which fluctuates in brightness and is best seen in complete darkness, lasts only a few minutes. This true afterimage can be attributed to the strong oscillatory neuronal responses immediately initiated by the flash.

Apparent size and receptive field properties.

A light square against a dark background besides an equisized dark square against a light background shows a difference in apparent size such that the light square seems larger than the dark one. This illusion was studied for squares of 109 x 109 min arc. Their centres were located 90 min arc out of the centre of the fovea.