Evaluation of the behavioral roles of ascending auditory interneurons in calling song phonotaxis by the female cricket (Acheta domesticus)

Abstract

1. Inactivating one L 1 results in angular errors and circling during orientation toward the side having the intact L1 in response to calling songs (CSs) whose intensities are below the threshold for L3 (Figs. 2, 3A). When song intensities are increased above the threshold of L3, circling decreases (Fig. 3B).2. Following inactivation of one L1 and occlusion of the ear providing input to the intact L1, no phonotaxis occurs in response to CSs at 60 dB (below the threshold of L3; Fig. 4A) demonstrating the necessity of L1 for phonotaxis. Orientation, at large and consistent angular errors (Fig. 5A) and circling (Fig. 5B) to the unoccluded side resumes when song intensities are increased above the threshold of L3 (Fig. 4B) suggesting that a single L3 can induce phonotactic responses.3. Inactivation of one L3 causes angular errors in orientation when CSs are above its threshold (Figs. 6A, 7), which are not apparent when CSs are below L3's threshold (Figs. 6B, 7).4. Inactivation of one L3 and occlusion of the ear providing input to the contralateral L1 and L3, leave only one L1 functioning. This results in turning and circling toward the unoccluded side containing the one functioning L1 (Figs. 6C, 8), thus confirming the sufficiency of L 1 for phonotaxis.

Distribution of synapses on two ascending interneurones carrying frequency‐specific information in the auditory system of the cricket: Evidence for gabaergic inputs

“…The difference in threshold between the two neurones is about 15-20 dB in favour of AN1 at 4-5 kHz and 30-50 dB in favour of AN2 at 15-40 kHz. The tuning curves of the two neurones were consistent in all experiments and we found neither physiological nor anatomical evidence for more than one neurone of each type, or for the presence of a third class of ascending interneurone as has been proposed in Acheta (Stout et al, 1985;Atkins et al, 1992). Our results therefore confirm previous work on Gryllus bimaculatus (Popov and Markovitch, 1982;Schildberger, 1984;Schildberger et al, 1986) as well as on other Gryllus or Teleogryllus species (Wohlers andHuber, 1982, 1985;Nolen and Hoy, 1987;Hennig, 1988) in demonstrating convincingly that AN1 and AN2 represent uniquely identifiable ascending auditory interneurones.…”

The L3 neuron and an associated prothoracic network are involved in calling song recognition by female crickets

“…Selverston et al, 1985, Stumpner et al, 1995. In old female A. domesticus inactivation (killed by illumination of a Luciferyellow filled neuron with blue laser, Atkins et al, 1992) of the ON 1 immediately enhanced both excitatory input and delayed inhibition while inactivation of the ON1 in young females had little effect on LYs responses (Atkins et al, 1997). Although the ON1 is present and functional in both young and old female A. domesticus (Stumpner et al, 1995), its inhibitory influence on the L3 neuron is greater in old females.…”

Processing of unilateral and bilateral auditory inputs by the ON1 and L1 interneurons of the cricket Acheta domesticus and comparison to other cricket species

“…Atkins et al 1992). For interneurons, only those data were used, for which morphology was available (except for two unequivocal ON1 recordings).…”

“…In all species investigated so far, one low-frequency type (AN1 in Gryllus and Teleogryllus, Wohlers and Huber 1982;Hennig 1988; L1 in Aeheta, Stout et al 1988) and at least one high-frequency type (AN2 in Gryllus, Popov and Markovich 1982;Wohlers and Huber 1982; Int-1 in Teleogryllus, Moiseff and Hoy 1983;L3 in Acheta, Atkins et al 1989) have been described. For Acheta, L1 has been shown to be of crucial importance for calling song phonotaxis (Atkins et al 1992). Although some physiological and morphological differences have been described, L1 seems to be functionally homologuous to AN1 in Gryllus (Schildberger and H6rner 1988).…”

“…These results, in combination with the behavioral results of killing the L1 (Atkins et al 1992) and ON1 (Atkins et al 1984) leads to better understanding of their roles in behavior.…”