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Regine Zopf

Publications and source records attributed to Regine Zopf.

3 recordsLinked to original sources
PubMed2004

Selective spatial attention to left or right hand flutter sensation modulates the steady-state somatosensory evoked potential.

Steady-state somatosensory evoked potentials (SSSEPs) were recorded from the scalp of human subjects elicited by 20 and 26 Hz mechanical vibrations applied simultaneously to the index finger of the left (20 Hz) and right hand (26 Hz). Subjects were instructed to attend to the flutter vibration at one finger while ignoring the other finger and to detect rare target events at the to-be-attended finger. The amplitude of the frequency coded SSSEP elicited by the attended vibration was significantly enlarged when attention was focused at the respective finger. This amplitude enhancement with attention was most prominent over fronto-central electrode locations contralateral to the attended finger. This is the first report to show the attentional modulation of the SSSEP amplitude in humans, suggesting an enhancement of neural responses in the sense of flutter with attention. The findings will open a new approach for studying the neural mechanisms of sustained selective attention in somatosensation.

Adult↗
PubMed2004

Attentional modulation of the human somatosensory evoked potential in a trial-by-trial spatial cueing and sustained spatial attention task measured with high density 128 channels EEG.

We investigated the modulation of the somatosensory evoked potential (SEP) elicited by mechanical stimuli in a spatial sustained attention and a spatial trial-by-trial cueing design by means of high density electrode array EEG recordings. Subjects were instructed to detect rare tactile target stimuli at the to-be-attended hand while ignoring stimuli at the other hand. Analysis of the SEP revealed a highly complex pattern of results. The P50 component was significantly increased for attended stimuli in the sustained attention as opposed to the trial-by-trial cueing condition. However, no difference in amplitude was found for attended as opposed to unattended stimuli. High density electrode array recordings revealed a centero-frontal N140 component (N140c), which preceded the parietal N140 (N140p) by about 20 ms. The N140c exhibited an attention effect in particular in the trial-by-trial spatial cueing condition. The N140p was significantly enlarged with attention across both experimental conditions, but a closer inspection demonstrated that this was mainly due to the great attention effect in the trial-by-trial spatial cueing condition. The late positive component (190-380 ms after stimulus onset) exhibited a significant attention effect in both experimental conditions. The present experiment provides evidence that the attentional modulation of the SEP is different when tactile as opposed to electrical stimuli were used and when only somatosensory stimuli are presented with no further sensory stimulation in other modalities. Furthermore, transient as opposed to sustained spatial attention affected various components of the SEP in a different way.

Adult↗