Search PubMed⌕ Search

Biomedical subjects

N Perrault

Publications and source records attributed to N Perrault.

4 recordsLinked to original sources
PubMed1984

Event-related potentials recorded from the scalp and nasopharynx. II. N2, P3 and slow wave.

Scalp and nasopharyngeal recordings of the N2, P3 and slow wave components were compared in a target-detection task. The effects of probability, interstimulus interval, intensity, discrimination difficulty, attention, stimulus omission and modality were evaluated. Waves of opposite polarity to the scalp N2 and P3 components were recorded in the nasopharynx. The scalp and nasopharyngeal N2 components showed different patterns of variation across experimental conditions. These findings indicate that there are two different cerebral processes occurring at the latency of the scalp N2. The scalp and nasopharyngeal P3 components consistently covaried across conditions, suggesting a single underlying process. The slow wave was observed only in the scalp recordings.

Attention↗
PubMed1984

Event-related potentials recorded from the scalp and nasopharynx. I. N1 and P2.

Event-related potentials were recorded from the scalp and nasopharynx during a signal-detection task. These responses were evaluated with respect to the effects of interstimulus interval, intensity, frequency, attention and modality. Our results indicate the existence of at least 4 distinct processes occurring in the 75-150 msec latency range following auditory stimuli. The first process is indexed in the vertex-N1b/temporal-N1a component. This component does not reverse in polarity below the sylvian fissure and is not seen in nasopharyngeal recordings. The location of its generator is not known. Probably there are two or more sources active at this latency. The second process finds reflection in the N1c/PgP120 component. This component is recorded with maximum amplitude on the side contralateral to the ear of delivery. A source in the lateral surface of the temporal lobe is a likely generator. The third process corresponds to Wolpaw and Penry's (1975) Ta positivity. How much of this represents the underside of a vertically oriented dipole and how much a surface positivity is unknown. Finally, during attention, a lateralized processing negativity seems to overlap these components at the scalp, but not at the nasopharynx. The auditory vertex N1 peak is quite distinct from the visual N1 which is more posteriorly recorded on the scalp and which is associated with a definite nasopharyngeal positive wave. The P2 peak is quite similar across auditory and visual modalities. In both modalities it is maximally recorded from the vertex and has no nasopharyngeal concomitant.

Adult↗