The Temperature Dependency of Cochlear Adaptation and Masking in the Guinea Pig

Abstract

The problem of the location of the adaptation mechanism in the peripheral hearing organ is studied using the temperature dependency of adaptation and masking of round window recorded AP in the guinea pig

At first, the influence of temperature on the synchronization conditions in the auditory nerve is investigated by observing the behaviour of the width-latency relation for the N₁. It is shown that cooling does not act in the same way as attenuating the stimulus but that the desynchronization caused is comparable to that by lowering the interstimulus interval (ISI). The competitive desynchronizing action of cooling on one side and adaptation and masking on the other side is discussed

Secondly, the temperature dependency of the An₁-ISI and An₁-S/N relations is studied. It became clear that, while the recovery time is not influenced by temperature, the decay time of the An₁ to its final value during a series of tone bursts is increased by lowering the temperature

The temperature dependency of synaptic mechanisms and the temperature dependency of adaptation and masking have been compared. This suggests that the chemical-enzymatic reactions in the synaps which take part in the release of transmitter and the formation of transmitter and the formation of transmitter receptor complexes are responsible for the adaptation for the adaptation phenomena in the peripheral hearing organ

Key Words:

• Hair cell neuron synaps
• Refractoriness
• Sensory physiology
• Temperature coefficients