Recovery Function of the Human Brain Stem Auditory-Evoked Potential

Abstract

Amplitude reduction and peak latency prolongation were observed in the human brain stem auditory-evoked potential (BEP) with preceding (conditioning) stimulation. At a conditioning interval (CI) of 5 ms the alteration of BEP was greater than at a CI of 10 ms. At a CI of 10 ms the amplitudes of some BEP components (e.g. waves I and II) were more decreased than those of others (e.g. wave V), while the peak latency prolongation did not show any obvious component selectivity. At a CI of 5 ms, the extent of the amplitude decrement of individual BEP components differed less, while the increase in the peak latencies of the later components was greater than that of the earlier components.

The alterations of the parameters of the test BEPs at both CIs are ascribed to the desynchronization of intrinsic neural events. The differential amplitude reduction at a CI of 10 ms is explained by the different durations of neural firings determining various effects of desynchronization upon the amplitudes of individual BEP components. The decrease in the extent of the component selectivity and the preferential increase in the peak latencies of the later BEP components observed at a CI of 5 ms are explained by the intensification of the mechanism of the relative refractory period.

Nous avons observé ce qui se passait au niveau des potentiels auditifs du tronc cérébral lorsqu'une stimulation de conditionnement était envoyée un peu plus tôt. C'est pour un intervalle de 5 ms que la diminution de Pamplitude et l'augmentation de la latence (surtout pour les dernières ondes) sont les plus fortes. Avec un intervalle de 10 ms, nous avons constaté une diminution de l'amplitude des premiers potentiels seulement (onde I et onde II), et pas d'augmentation de latence.

Nous discutons le mécanisme possible des phénomènes observés, en mettant l'accent sur le rôle joué par la désynchronisation.

Key Words:

• Brain stem auditory-evoked potential
• Conditioning paradigm
• Effects of desynchronization of neural firing
• Differential recovery of brain stem auditory-evoked potential components
• Mechanisms of the brain stem auditory-evoked potentials