[Inter-individual variability of mean latencies in the dynamic topography of short latency visual evoked potentials and the origin of brainstem potentials evaluated by the dipole tracing method in normal subjects].
To determine the normal pattern of the short latency visual evoked potentials (SVEP) in clinical diagnosis, in a previous report, the normal responses were classified into the following three types: uniform type, brainstem dominant type and occipital dominant type, according to the strength of the potentials. In the present report the latencies of N40 and P50, which constitute the SVEP, were investigated. In addition, the burst origin of these potentials was investigated using the dipole tracing method for P50 obtained through dynamic topography. Optic nerve potentials of N40 appeared first in the anterior region (from 37.1msec to 40.4msec following the stimulus) after the fourth retinal oscillatory potentials and soon extended to the posterior region (after about 2msec). This potential appeared in approximately about 65%, because of the low amplitude. P50 appeared 45.8-53.6msec after the stimulus about 100% and burst 2-4 times in the same place. Using the dipole tracing method, the origin of P50 was estimated to the near the deep center of the brain, probably around the brainstem. The same results were obtained using dynamic topography.
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D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods; D001933:Brain Stem / Q000502:physiology*; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual; D006801:Humans; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values