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

Abstract

1. When tested with legphone stimulation at 5 and 16 kHz, two prothoracic 'low-frequency neurons', ON1 and L1 of Acheta domesticus females, receive mainly excitation from one side (soma-ipsilateral in ON1, soma-contralateral in L1) and inhibition from the opposite side as is described for other cricket species (Figs. 2,3). While thresholds at 5 kHz are similar in L1 and ON1, L1 receives 16 kHz excitation with a 15 -20 dB higher threshold (lower than in other cricket species) than ON1. Stimulation of L1 with lower intensity 16 kHz sound on the side of its major input results in a clear IPSP visible in dendritic recordings (Figs. 3,4). In L1 and ON1 the intensity response at 16 kHz rises steeper than that at 5 kHz. 2. The most sensitive auditory low-frequency receptors recorded have similar thresholds as ON1 and L1 at 5 kHz. Responses of the most sensitive auditory highfrequency receptors recorded show an intensity dependence which is similar to that of ON1 at 16 k Hz (Fig. 1C). 3. Results of two-tone experiments show a tuning of inhibition in ON1 and L1 which is similar to excitatory tuning of ON1 (Fig. 4), however with about 10 to 15 dB higher thresholds. In contrast, in Gryllus bimaculatus an exact match between ONl-excitation and ON1/AN1 inhibition has been described.

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

“…These correlations suggest that the L3 neuron may be involved in the recognition of the conspecific male's CS. Both the L3 and the L1 auditory interneurons of female A. domesticus (homologous to the first order AN2 and AN1 auditory interneurons of other cricket species; Hennig 1985, Stout et al, 1985, Stumpner et al, 1995 respond to the male's calling song, encode its temporal structure, and project to similar areas in the brain. However the L1 neuron does not respond selectively to the SPs of model CSs , Stumpner et al, 1995.…”

“…Both the L3 and the L1 auditory interneurons of female A. domesticus (homologous to the first order AN2 and AN1 auditory interneurons of other cricket species; Hennig 1985, Stout et al, 1985, Stumpner et al, 1995 respond to the male's calling song, encode its temporal structure, and project to similar areas in the brain. However the L1 neuron does not respond selectively to the SPs of model CSs , Stumpner et al, 1995. Thresholds for the L3 neuron's response to 5 kHz CSs range between 65 and 70 dB in both young and old females (Atkins et al, 1989 while L1 thresholds range between 45 and 50 dB (Stout et al, 1989, Stumpner et al, 1995.…”

Processing of auditory information in insects

“…Modified after (A) Römer (1987), (B) Stumpner (1996Stumpner ( , 1997, (C) Stumpner (1999b), (D) Römer (1976), and Römer et al (1988), (E) (grasshopper) Marquart (1985a). Esch et al (1980), Schildberger (1984), Oldfield et al (1986), Schildberger et al (1986), Horseman and Huber (1994), Watson and Hardt (1996); G. campestris, Wohlers and Huber (1978), Boyd et al (1984); Acheta domesticus, Stout et al (1988), Stumpner et al (1995); Teleogryllus oceanicus, Atkins and Pollack (1986), Atkins et al (1988Atkins et al ( , 1989; T. commodus, Ball and Hill (1978), Hennig (1988). Molecrickets: Scapteriscus borealis, Mason et al (1998).…”

“…As a solution to this problem, insects might use different channels for coding different information like carrier frequency and temporal pattern. However, for crickets it seems that single interneurons like AN1 carry information about carrier frequency as well as temporal pattern although they receive frequency-specific and directional inhibitions (e.g., Schildberger, 1984;Horseman and Huber, 1994;Stumpner et al, 1995; see also Serial or Parallel Processing of Directional and Pattern Information). This may be tolerable since the effect of the inhibitory influence seems to be less strong than in certain bushcricket neurons (e.g., AN1 of A. nigrovittata, the homologous neuron to AN1 of crickets; Stumpner, 1997).…”

Stay tuned: active amplification tunes tree cricket ears to track temperature-dependent song frequency

“…It is important to note that the threshold achieved by the actively amplified O. nigricornis auditory system, at about 45 dB SPL, is similar to ON1 thresholds in field crickets [13,16,17]. Indeed, even at the very highest observed amplification, O. nigricornis tympana rarely achieve mechanical sensitivity higher than G. assimilis ( figure 1; electronic supplementary material, figure S1, [5]).…”