Motion aftereffects with rotating ellipses

Summary The perceptual outcome and the motion-aftereffect duration generated by the rotation on the frontal plane of an ellipse with a bar depend on whether the bar is placed along the major or the minor axis. When the bar is placed along the minor axis, a stereokinetic transformation occurs, and the pattern looks like a tilting ring with a perpendicular bar moving rigidly with it. Placing the bar along the major axis prevents the stereokinetic transformation: subjects report deformations and relative motion of the bar with respect to the ellipse. We found that motion aftereffects last longer when the bar is placed along the minor rather than along the major axis. A series of experiments was carried out to investigate whether differences in aftereffect duration are related to the stereokinetic transformation. Results seem to suggest that they are not.The authors' names are in alphabetical order.     

Common functional pathways for texture and form vision: A single case study

A single case study of a patient, D.M., with a lesion in the region of the right occipito-temporal gyrus is presented. D.M. had well-preserved language and general cognitive abilities. Colour discrimination, contrast sensitivity, gross depth perception, spatial localization, and motion appreciation were within normal limits.On the evaluation of perceptual abilities, he failed to identify two-dimensional shapes from stereoscopic vision, motion, and texture although in all cases he was able to identify the rough area subtended by the shape. These findings are considered in relation to the current anatomical-physiological functional models of vision and it is suggested that D.M.'s deficits provide evidence for the existence in man of a functional pathway involved in the computation of texture and fine aspects of shape, which is distinct from the pathways involved in motion and stereopsis processing on one hand and colour and coarse aspects of form on the other hand.     

Akinetopsia,achromatopsia and blindsight: Recent studies on perception without awareness

The neural substrate of early visual processing in the macaque is used as a framework to discuss recent progress towards a precise anatomical localization and understanding of the functional implications of the syndromes of blindsight, achromatopsia and akinetopsia in humans. This review is mainly concerned with how these syndromes support the principles of organization of the visual system into parallel pathways and the functional hierarchy of visual mechanisms.     

The role of lexical stress in word recognition and pronunciation

Summary In the present paper several studies are reviewed that are relevant to lexical-stress assignment. The questions asked concern the form of representation of stress and its role in the perception and identification of words in auditory and visual word recognition. The role of stress is also considered in the computation of phonology, as are the linguistic and orthographic constraints that influence its assignment during reading.