RESPONSE OF CERCAL RECEPTORS AND IDENTIFIED INTERNEURONS IN THE CRICKET (ACHETA-DOMESTICUS) TO AIRSTREAMS

The directional properties of cereal afferents and the interneurons they innervate in the abdominal giant fiber system of the cricket (Acheta domesticus) were studied using laminar flow airstreams as a stimulus. 2. Each sensory neuron was excited when its associated mechanoreceptive hair was deflected in one direction. Background activity in these neurons was blocked when the hair was deflected in the polar opposite direction suggesting that the cell was hyperpolarized when deflected in the null direction (Fig. 1). 3. Each of the two morphological classes of receptor hair previously described (T-hairs and L-hairs) could be further subdivided into two types on physiological grounds. One type was excited when the hairs were deflected in one direction, consistent with their hinge plane, while others were excited when moved in the opposite direction (Fig. 2). 4. Two uniquely identified interneurons responded preferentially to airstreams directed at the specimen from positions ipsilateral to the giant axons (Figs. 3 and 4). 5. The directional response properties of the interneurons can be understood as the sum of excitatory input via the receptors on one cercus and inhibitory input from the other cercus. 6. Maximal activation of the interneurons occurs when T-hairs, on the cercus ipsilateral to the axons of the interneurons, are deflected toward the midline or L-hairs, on the same cercus, are deflected toward the body (Fig. 7). © 1979 Springer-Verlag.