Cortical potentials reflecting motion processing in humans

Abstract

Motion processing is a fundamental task of visual systems, and in the monkey cortical areas can be identified which appear to be functionally specialized for motion processing. The human visual system is expected to be organized in a similar way. A noninvasive method to study the functional organization of the visual cortex is the recording of scalp potentials generated by neural activity of the underlying cortical areas. In the present study, we recorded slow cortical potentials from normal subjects in order to investigate how motion stimuli are processed. Three classes of object motion were realized as random dot kinematograms, namely Fourier motion, drift-balanced motion, and theta motion, because they require mechanisms of increasing complexity in order to be extracted. Large-field motion and counterphase flicker were used as control stimuli. Three basic results were obtained: (1) The responses evoked by the three classes of object motion do not differ significantly in their time course and distribution of activation.(2) The distributions of cortical activation evoked by object motion, and the control stimuli are different. During object motion the maximum activation occurs over the superior parietal cortex. Large-field motion activates occipital and parietal locations to the same extent, and during counterphase flicker the activity is maximum over the occipital lobe. Thus, the parietal slow potentials are interpreted to specifically reflect the cortical processing of object motion. (3) The time course of the activation reflects changes in the spatial position of the object: the amplitude of a transient negative component (TNC) which occurs 240 ms after motion onset decreases with increasing eccentricity of motion onset. The consecutive sustained negative component (SNC), which persists until the movement stops, decreases during centrifugal and increases during centripetal object motion. These results can be understood on the basis of physiological and anatomical knowledge about the mapping of the visual field on the cortex.

Individual differences in children’s global motion sensitivity correlate with TBSS-based measures of the superior longitudinal fasciculus

“…However, there does not appear to be any consistent difference across individuals between left and right hemispheres in these responses, which might be associated with the asymmetric anatomical relationships we find with motion coherence thresholds. An exception is an overall right-hemisphere advantage reported by Patzwahl et al (1994), which is ascribed by them to “[the special role of the right hemisphere] attentional system amplifying the activation of the right parietal cortex”. In contrast, Hollants-Gilhuijs et al (1998) found a behavioral advantage for right-field motion detection (implying left-hemisphere advantage) in 6- to 16-year-old children (but not in adults), which they ascribed to differential maturation of extra-striate areas in the two hemispheres.…”

“…A number of reports find that individual participants show hemispheric asymmetries in cerebral responses to motion, for example, Patzwahl et al, (1994), Hollants-Gilhuijs et al (2000), and Nakamura et al, (2003), which they ascribe to area V5/MT. However, there does not appear to be any consistent difference across individuals between left and right hemispheres in these responses, which might be associated with the asymmetric anatomical relationships we find with motion coherence thresholds.…”

A primer on motion visual evoked potentials

“…Patzwahl et al [79] were an exception. They used DC amplifiers to record sustained neural activation to ongoing object motion.…”

Electrophysiological evidence for the magnocellular‐dorsal pathway deficit in dyslexia

“…correlated motion of pixels) led to a right hemispheric N2 amplitude advantage when compared to the onset of random motion (i.e. uncorrelated motion of pixels) (Patzwahl, Zanker & Altenmuller, 1994; Niedeggen & Wist, 1999). In these studies a lateralization of N2 was found even though the stimuli were presented centrally.…”