PubMed Health⌕ Search

PubMed · 6874248

High-frequency components of human visual evoked potentials.

Abstract

This study was aimed to further our investigations on the high frequency components of human visual evoked potentials (VEP). By using stimulations in the form of optic step functions, we measured (Cz-ear lobe) VEPs with 512 real data points in a total recording time of 20.48 msec in normal adults (N = 12). The peaks in the transient evoked potentials occurred with approximate latencies of 0.5, 1.0, 1.5, 2.5 and 5.0 msec. Transforming the individual time responses to the frequency domain by the Fourier Transform, maxima were obtained in 200, 400, 700, 1200 and 2200 Hz positions in the amplitude frequency characteristics. The findings were compared with those of a similar study on the auditory system. It is stated that the response activities of 200 Hz and 2200 Hz are unique to the visual system.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S Karakaş, E Başar. 1983. High-frequency components of human visual evoked potentials.. https://doi.org/10.3109/00207458309148652

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

[Neurophysiolgical analysis in an 18-month-old girl with Gaucher's disease type 2].

Gaucher's disease is caused by a lack of glucocerebrosidase, and in type 2 various neurological symptoms can occur;however, the detailed pathogenesis of the condition remains undetermined. Here we performed neurophysiological examinations in an 18-month-old girl with Gaucher's disease type 2 to specify the brainstem lesions. Developmental delay occurred from the age of 8 months, and the patient subsequently showed strabismus, loss of head control, failure to thrive and irregular respiration. She was admitted to our hospital at the age of 18 months. A definite diagnosis of Gaucher's disease type 2 was made from the presence of Gaucher cells and reduced glucocerebrosidase activity. Clinically, limited ocular movements, poor facial expression and bulbar palsy indicated disturbances in the nuclei of oculomotor, trochlear, abducent, facial and ambiguous nerves, although magnetic resonance imaging (MRI) failed to visualize any structural changes in the brain including the brainstem. Neurophysiologically, auditory brainstem response and somatosensory evoked potential demonstrated lesions in the cochlear nucleus and medial lemniscus, respectively. On polysomnography, disturbed sleep parameters during rapid eye movement sleep, in addition to the lack of modification of respiratory patterns by sleep stage, suggested dysfunctions in the locus ceruleus, raphe nuclei and pontine reticular formations. It is likely that these neurophysiological tests can be useful to identify functional lesions that are not detectable by MRI, and should help exploit new treatments for child-onset neurodegenerative disorders such as Gaucher's disease.

Evoked Potentials, Auditory↗

A template-free approach for determining the latency of single events of auditory evoked M100.

The phase of the complex output of a narrow band Gaussian filter is taken to define the latency of the auditory evoked response M100 recorded by magnetoencephalography. It is demonstrated that this definition is consistent with the conventional peak latency. Moreover, it provides a tool for reducing the number of averages needed for a reliable estimation of the latency. Single-event latencies obtained by this procedure can be used to improve the signal quality of the conventional average by latency adjusted averaging.

Evoked Potentials, Auditory↗