SOME ELECTRICAL-PROPERTIES OF THE CERCAL ANEMORECEPTORS OF THE COCKROACH, PERIPLANETA-AMERICANA

The responses of cercal filiform sensilla (anemoreceptors) of the cock roach, Periplaneta americana to mechanical and electrical stimuli were investigated by recording from hairs cut near their base. The sensory neurons associated with short hairs (L < 200 mu m) were silent at res t, whereas those connected to longer hairs were spontaneously active. The receptor potentials evoked by deflecting the hair were always phas ic, but compressions and other mechanical stresses induced phasico-ton ic receptor potentials. The responses to electrical polarizations exhi bited a strong tonic component. Therefore, tbe complete adaptation obs erved during deflections was not due to the spike generator. The negat ive component of spikes was reduced both by positive and negative pola rizations, which contrasts with the results previously reported for ma ny other insect mechanosensilla.