Experimental contribution to the origin of brain-stem potentials.

The origin of the different BSP waves is open to discussion. In this work we analyze the response curves with surface and intranuclear electrodes in cats, both before and after inducing electrolytic lesions in acute and chronic phase, in order to study the subsequent alterations. We found that waves whose origins are attributed to specific regions of the acoustic pathway when carried out with surface electrodes, fail to correspond with the results obtained by intranuclear electrodes. On the other hand, although the lesions to the lowest part of the acoustic pathway (cochlear nuclei) cause important alterations in the recordings, these alterations become smaller as the lesions are induced higher up the pathway. Thus, we believe that the origin of the different BSP waves is due to the sum of potentials of different zones of neuron activation, and not to specific locations of the acoustic pathway; this is more evident in the delayed waves.