02385nas a2200229 4500008004100000245013300041210007000174520162100244653001301865653002501878653001201903653003801915653001101953653002501964653002501989653002502014653000902039653002702048100001502075700002402090856004102114 2001 eng d00aMechanisms of frequency-specific responses of ω neuron 1 in crickets (Teleogryllus oceanicus): a polysynaptic pathway for song?0 aMechanisms of frequencyspecific responses of ω neuron 1 in crick3 a

In crickets (Teleogryllus oceanicus), the auditory interneuron ω neuron 1 (ON1) responds to sounds over a wide range of frequencies but is most sensitive to the frequency of conspecific songs (4.5 kHz). Response latency is longest for this same frequency. We investigate the mechanisms that might account for the longer latency of ON1 to cricket-like sounds. Intracellular recordings revealed no evidence for appropriately timed postsynaptic inhibition of ON1 that might increase its latency, nor was latency affected by picrotoxin. The onset of excitatory postsynaptic potentials (EPSPs) was delayed for 4.5 kHz stimuli compared with ultrasound stimuli, pointing to a presynaptic locus for the latency difference. When ON1 is stimulated with high frequencies, discrete, apparently unitary EPSPs can be recorded in its dendrite, and these are latency-locked to spikes recorded simultaneously in the auditory nerve. This suggests that input to ON1 from high-frequency-tuned auditory receptor neurons is monosynaptic. In agreement with this, brief ultrasound stimuli evoke a single, short-latency EPSP in ON1. In contrast, the EPSP evoked by a brief 4.5 kHz stimulus consists of an early component, similar in latency to that evoked by ultrasound and possibly evoked by ultrasound-tuned receptors, and a later, dominant component. We interpret the early peak as arising from a monosynaptic afferent pathway and the late peak from a polysynaptic afferent pathway. Multiple-peak EPSPs, with timing similar to those evoked by sound stimuli, were also evoked by electrical stimulation of the auditory nerve.

10aaudition10aauditory interneuron10acricket10aexcitatory postsynaptic potential10aInsect10amonosynaptic pathway10aomega neuron 1 (ON1)10apolysynaptic pathway10asong10aTeleogryllus oceanicus1 aFaulkes, Z1 aPollack, Gerald, S. uhttps://bio.acousti.ca/uk/node/5762001824nas a2200205 4500008004100000245012200041210006900163300001200232490000800244520115400252653002701406653003001433653001201463653001901475653002701494653001501521100002401536700001701560856004101577 1998 eng d00aRepresentation of behaviorally relevant sound frequencies by auditory receptors in the cricket teleogryllus oceanicus0 aRepresentation of behaviorally relevant sound frequencies by aud a155-1630 v2013 a

Teleogryllus oceanicus is particularly sensitive to two ranges of sound frequency, one corresponding to intraspecific acoustical signals (4-5 kHz) and the other to the echolocation cries of bats (25-50 kHz). We recorded summed responses of the auditory nerve to stimuli in these two ranges. Nerve responses consist of trains of compound action potentials (CAPs), each produced by the summed activity of a number of receptor neurons. The amplitude of the CAP is up to four times larger for stimuli at 4.5 kHz than for stimuli at 30 kHz, suggesting either that the extracellular spikes produced by receptors that respond to 4.5 kHz are larger than those that respond to 30 kHz, or that receptors fire more synchronously in response to stimulation at 4.5 kHz, or that more receptors respond to stimulation at 4.5 kHz. Neither unit spike amplitude nor conduction velocity (which is expected to vary with spike amplitude) differs for the two frequencies, and the responses to 4.5 kHz are not produced by more tightly synchronized receptor populations, as judged by CAP breadth. We conclude that more receptors respond to 4. 5 kHz than to 30 kHz.

10aacoustic communication10acompound action potential10acricket10asensory coding10aTeleogryllus oceanicus10aultrasound1 aPollack, Gerald, S.1 aFaulkes, Zen uhttps://bio.acousti.ca/uk/node/5761802220nas a2200181 4500008004100000245009000041210006900131520162800200653001301828653001801841653001201859653002301871653001501894653002001909100001701929700002401946856006801970 2005 eng d00aEffect of the Temporal Pattern of Contralateral Inhibition on Sound Localization Cues0 aEffect of the Temporal Pattern of Contralateral Inhibition on So3 a

We studied the temporal coding properties of identified interneurons in the auditory system of crickets, using information theory as an analytical tool. The ascending neuron 1 (AN1), which is tuned to the dominant carrier frequency (CF) of cricket songs, selectively codes the limited range of amplitude modulation (AM) frequencies that occur in these signals. AN2, which is most sensitive to the ultrasonic frequencies that occur in echolocation calls of insectivorous bats, codes a broader range of AM frequencies, as occur in bat calls. A third neuron, omega neuron 1 (ON1), which is dually tuned to both ranges of carrier frequency, was shown previously to have CF-specific coding properties, allowing it to represent accurately the differing temporal structures of both cricket songs and bat calls. ON1 is a source of contralateral inhibition to AN1 and AN2, enhancing binaural contrast and facilitating sound localization. We used dichotic stimulation to examine the importance of the temporal structure of contralateral inhibition for enhancing binaural contrast. Contralateral inhibition degrades the coding of temporal pattern by AN1 and AN2, but only if the temporal pattern of inhibitory input matches that of excitation. Firing rate is also decreased most strongly by temporally matched contralateral inhibition. This is apparent for AN1 in its mean firing rate; for AN2, high-frequency firing is selectively suppressed. Our results show that the CF-specific coding properties of ON1 allow this single neuron to enhance effectively localization cues for both cricket-like and bat-like acoustic signals.

10aauditory10acommunication10acricket10ainformation theory10aphonotaxis10atemporal coding1 aMarsat, Gary1 aPollack, Gerald, S. uhttp://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.0646-05.2005