ABSTRACT
The physiological properties of hair sensilla found on the metathoracic tarsal segments of the locust and grasshopper are described.
The sensilla trichodea are phasically responsive mechanoreceptors. The discharge frequency of these receptors is proportional to the velocity of displacement of the sensory appendage. Phase-related responses are obtained with sinusoidal inputs less than 100 Hz. With higher input frequencies the receptors respond asynchronously.
The tarsal sensilla signal contact of the tarsal segments with the substratum and changes in the load on the metathoracic leg.
Reflexes involving these tarsal receptors and the ‘fast’ and ‘slow’ excitatory and inhibitory neurones which innervate the metathoracic extensor tibiae muscle have been demonstrated and appear to play a significant role during postural and walking activity.
