The Experimental Study of BSR

The changes of Brain Stem Response (BSR) recorded from vertex of adult cats were studied under a series of lesion experiments with inferior colliculus and several parts of brain stem.The results were as follows:1. The typical wave forms of BSR in cat consisted of 4 to 6 evoked potentials and the latencies of these potentials were 1.45±0.09, 2.35±0.12, 3.18±0.15, 4.38±0.16, 6.08±0.32, 7.6 msec.2. BSR was not affected by the using of muscle relaxant and the bilateral destruction at the level of the superior colliculi.3. The first to third potentials remained unchanged by bilateral aspiration of the inferior colliculi.4. The fourth and fifth potentials disappeared by aspiration of the bilateral inferior colliculi.5. The fifth potential greatly diminished by aspiration of the contralateral inferior colliculus which was the opposite side of the stimulating ear.The conclusions are follows:1. BSR is the acoustically evoked response which has no myogenic component.2. The first to third potentials are generated at the lower brain stem auditory pathway except the inferior collieulus.3. The fourth potentials are mainly evoked at the inferior colliculi bilaterally.4. The fifth potential is mainly evoked at the contralateral inferior colliculus which is the opposite side of the stimulating ear.