The effects of injury on mammalian nerve fibres

Abstract

When a nerve is removed from a frog and connected with an amplifier and recording system, occasional impulses appear if the fibres are allowed to dry and a short discharge can be produced by pinching or cutting, but if drying is prevented there is no sign of activity except during the actual infliction of an injury. Mammalian nerves give a very different picture. In a mediumsized nerve trunk from the cat or rabbit, set up in a moist, warm atmosphere, large and rapid fluctuations of potential are nearly always present and the disturbance may last for an hour or more in spite of repeated irrigation. Very small nerves may give a steady base line and in nerves prepared for recording motor or sensory discharges a disturbance, initially present, may subside during the exposure and manipulation, but in all mammalian experiments the danger of an unsteady background is increasingly present as the condition of the nerve is a closer and closer approach to the normal.