Influence of syllable period on song encoding properties of an ascending auditory interneuron in the cricketAcheta domestica

1989 ◽  
Vol 165 (6) ◽  
pp. 827-836 ◽  
Author(s):  
Steven Atkins ◽  
Gordon Atkins ◽  
Mike Rhodes ◽  
John F. Stout
Keyword(s):  
Auditory Interneuron

scholarly journals Phonotactic steering and representation of directional information in the ascending auditory pathway of a cricket

2020 ◽  
Vol 123 (3) ◽  
pp. 865-875 ◽  
Author(s):  
M. Lv ◽  
X. Zhang ◽  
B. Hedwig
Keyword(s):  
Longitudinal Axis ◽  
Auditory Pathway ◽  
Response Strength ◽  
Acoustic Stimulation ◽  
Directional Hearing ◽  
Directional Information ◽  
Significant Difference ◽  
Auditory Interneuron ◽  
Bilateral Differences ◽  
The Brain

Directional hearing is crucial for animals depending on acoustic signals to locate a mate. We focused on crickets to explore the reliability of directional information forwarded to the brain by the ascending auditory interneuron AN1, which is crucial for phonotactic behavior. We presented calling song from −45° to +45° in steps of 3° and compared the phonotactic steering of females walking on a trackball with the directional responses of AN1. Forty percent of females showed good steering behavior and changed their walking direction when the speaker passed the body’s longitudinal axis. The bilateral latency difference between right and left AN1 responses was small and may not be reliable for auditory steering. In respect to spike count, all AN1 recordings presented significant bilateral differences for angles larger than ±18°, yet 35% showed a mean significant difference of 1–3 action potentials per chirp when the frontal stimulus deviated by 3° from their length axis. For small angles, some females had a very similar AN1 activity forwarded to the brain, but the accuracy of their steering behavior was substantially different. Our results indicate a correlation between directional steering and the response strength of AN1, especially for large angles. The reliable steering of animals at small angles would have to be based on small bilateral differences of AN1 activity, if AN1 is the only source providing directional information. We discuss whether such bilateral response difference at small angles can provide a reliable measure to generate auditory steering commands descending from the brain, as pattern recognition is intensity independent. NEW & NOTEWORTHY The ascending auditory interneuron AN1 has been implicated in cricket auditory steering, but at small acoustic stimulation angles, it does not provide reliable directional information. We conclude that either the small bilateral auditory activity differences of the AN1 neurons are enhanced to generate reliable descending steering commands or, more likely, directional auditory steering is mediated via a thoracic pathway, as indicated by the reactive steering hypothesis.

Neuroethology of the katydid T-cell. I. Tuning and responses to pure tones

2000 ◽  
Vol 203 (21) ◽  
pp. 3225-3242 ◽  
Author(s):  
P.A. Faure ◽  
R.R. Hoy
Keyword(s):  
T Cell ◽  
Pure Tone ◽  
T Cell Responses ◽  
Integration Time ◽  
High Frequency Ultrasound ◽  
Cell Responses ◽  
T Cell Stimulation ◽  
Auditory Interneuron ◽  
Contralateral Ear ◽  
Ultrasonic Stimulation

The tuning and pure-tone physiology of the T-cell prothoracic auditory interneuron were investigated in the nocturnal katydid Neoconocephalus ensiger. The T-cell is extremely sensitive and broadly tuned, particularly to high-frequency ultrasound (>20 kHz). Adult thresholds were lowest and showed their least variability for frequencies ranging from 25 to 80 kHz. The average best threshold of the T-cell in N. ensiger ranged from 28 to 38 dB SPL and the best frequency from 20 to 27 kHz. In females, the T-cell is slightly more sensitive to the range of frequencies encompassing the spectrum of male song. Tuning of the T-cell in non-volant nymphs was comparable with that of adults, and this precocious ultrasound sensitivity supports the view that it has a role in the detection of terrestrial sources of predaceous ultrasound. In adults, T-cell tuning is narrower than that of the whole auditory (tympanic) organ, but only at audio frequencies. Superthreshold physiological experiments revealed that T-cell responses were ultrasound-biased, with intensity/response functions steeper and spike latencies shorter at 20, 30 and 40 kHz than at 5, 10 and 15 kHz. The same was also true for T-cell stimulation at 90 degrees compared with stimulation at 0 degrees within a frequency, which supports early T-cell research showing that excitation of the contralateral ear inhibits ipsilateral T-cell responses. In a temporal summation experiment, the integration time of the T-cell at 40 kHz (integration time constant tau =6.1 ms) was less than half that measured at 15 kHz (tau =15.0 ms). Moreover, T-cell spiking in response to short-duration pure-tone trains mimicking calling conspecifics (15 kHz) and bat echolocation hunting sequences (40 kHz) revealed that temporal pattern-copying was superior for ultrasonic stimulation. Apparently, T-cell responses are reduced or inhibited by stimulation with audio frequencies, which leads to the prediction that the T-cell will encode conspecific song less well than bat-like frequency-modulated sweeps during acoustic playback. The fact that the T-cell is one of the most sensitive ultrasound neurons in tympanate insects is most consistent with it serving an alarm, warning or escape function in both volant and non-volant katydids (nymphs and adults).

scholarly journals Dynamic dendritic compartmentalization underlies stimulus-specific adaptation in an insect neuron

2015 ◽  
Vol 113 (10) ◽  
pp. 3787-3797 ◽  
Author(s):  
Janez Prešern ◽  
Jeffrey D. Triblehorn ◽  
Johannes Schul
Keyword(s):  
Pulse Rate ◽  
Imaging Techniques ◽  
Calcium Signal ◽  
Specific Adaptation ◽  
Sodium Accumulation ◽  
Auditory Interneuron ◽  
Time Courses ◽  
Underlying Mechanisms ◽  
Neuroanatomical Data ◽  
Fast Pulse

In many neural systems, repeated stimulation leads to stimulus-specific adaptation (SSA), with responses to repeated signals being reduced while responses to novel stimuli remain unaffected. The underlying mechanisms of SSA remain mostly hypothetical. One hypothesis is that dendritic processes generate SSA. Evidence for such a mechanism was recently described in an insect auditory interneuron (TN-1 in Neoconocephalus triops). Afferents, tuned to different frequencies, connect with different parts of the TN-1 dendrite. The specific adaptation of these inputs relies on calcium and sodium accumulation within the dendrite, with calcium having a transient and sodium a tonic effect. Using imaging techniques, we tested here whether the accumulation of these ions remained limited to the stimulated parts of the dendrite. Stimulation with a fast pulse rate, which results in strong adaptation, elicited a transient dendritic calcium signal. In contrast, the sodium signal was tonic, remaining high during the fast pulse rate stimulus. These time courses followed the predictions from the previous pharmacological experiments. The peak positions of the calcium and sodium signals differed with the carrier frequency of the stimulus; at 15 kHz, peak locations were significantly more rostral than at 40 kHz. This matched the predictions made from neuroanatomical data. Our findings confirm that excitatory postsynaptic potentials rather than spiking cause the increase of dendritic calcium and sodium concentrations and that these increases remain limited to the stimulated parts of the dendrite. This supports the hypothesis of “dynamic dendritic compartmentalization” underlying SSA in this auditory interneuron.

Carrier-dependent temporal processing in an auditory interneuron

2008 ◽  
Vol 123 (5) ◽  
pp. 2910-2917 ◽  
Author(s):  
Patrick Sabourin ◽  
Heather Gottlieb ◽  
Gerald S. Pollack
Keyword(s):  
Temporal Processing ◽  
Auditory Interneuron
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