[What effect does ligation of the large neck arteries have on cochlear potentials?]

In guinea-pigs the course of summating potentials (SP) is observed. After the potentials have been identified by their typical form, their sensitivity to a reduction of oxygen, damage by streptomycin and adaptation to excessive noise, the quantity of the SP after ligature of the main neck arteries is recorded. After ligature of the external carotid arteries, the internal carotid arteries and the vertebral arteries on both sides, the SP remain active. This is presumably caused by anastomoses between the external carotid and subclavian arteries, the subclavian and spinal arteries, the external carotid and basilar arteries, and the double origin of the vertebral arteries on both sides. The subclavian arteries and the common carotid arteries can be ligated on both sides in random order. The SP remain almost unchanged as long as one vessel is open.