A study of the surface wave propagation in the cnv

The aim of this research has been to study the spatio-temporal features of some components of the CNV complex. the significant Event-Related Potential first described by Walter et al. [1], and in particular of the N100 wave, a complex negative potential whose highest peak, the so-called N100 vertex potential, occurs at approximately 0.1 s after the auditory or visual stimuli. The N100 negative shift is composed of a group of overlapped subcomponents which are produced by the bioelectrical activity of bihemispheric cortical generators. These generators are sensory-modality specific and are different in their topographic distribution and neuro-psychophysiological meaning. The N100 vertex potential depends not only on the physical properties of the external stimuli, but also on the attention level of the subjects [2, 3]. A problem which presents remarkable difficulty is the localization of the different generators of the various subcomponents of the auditory N100 vertex potential, i.e. N100a (preceding the highest wave peak), N100b (including the peak), and N100c (subsequent to the peak and with more frontal distribution), which are evoked by warning signals. Recently the hypothesis has been advanced that the homohemispheric corticocortical pathways connecting associative parieto-temporo-occipital regions with prefrontal areas play an important role in the generation of some post-S1 and more generai CNV components [3. 4]. So far, we have limited our investigation to the analysis of parameters which might be able to describe the suriace tangential propagation speed of some of these cortical neurocognitive potentials.