The Linguo‐Chorda Tympani Reflex—an Electrophysiologically Undescribed Reflex

The impulse activity in the central part of the chorda tympani nerve of the rat was recorded during mechanical stimulation of the oral region. The results obtained at a stimulation rate of 1 Hz show that a) a reflex discharge could be recorded about 6–10 ms after stimulation of the ipsilateral side of the tongue, b) stimulation of the contralateral side increased the latency by about 1–1.5 ms, c) the reflex could be evoked in animals which showed no spontaneous efferent activity in the chorda tympani nerve, d) recordings from nerve filaments showed that a filament could display spontaneous activity without being involved in the reflex, e) the lingual nerve serves as the main sensory link on the reflex to mechanical stimulation of the anterior part of the tongue, and f) the reflex evoked by stimulation of other parts of the oral region had a longer latency and less intense discharge. The results obtained at higher stimulation rate show that a) individual bursts of reflex discharge could be traced at stimulation frequencies up to 60 Hz, b) except for a moderate decrease the discharge did not disappear when stimulus frequencies of 5, 30 and 50 Hz were used.