Postsynaptic inhibition mediates high-frequency selectivity in the cricket Teleogryllus oceanicus: implications for flight phonotaxis behavior.
Level 5 - mechanism / opinion, no new human data
Non-clinical basic neurobiology and animal physiology study.
PubMed 3612230 · doi:10.1523/JNEUROSCI.07-07-02081.1987
What was done
Researchers investigated the frequency selectivity mechanisms of the identified auditory interneuron Int-1 in the cricket *Teleogryllus oceanicus* using intracellular recording and staining techniques during exposure to acoustic stimuli ranging from 3 to 40 kHz, comparing responses between low-frequency calling songs (4–5 kHz) and high-frequency ultrasound (>20 kHz).
What was found
Int-1 was excited by acoustic stimuli from 3 to 40 kHz but responded differentially across frequencies. Ultrasound (>20 kHz) elicited discharge rates up to 400 spikes/sec, response latencies of 10 ms, and an operating dynamic range of approximately 50 dB. In contrast, calling song frequencies elicited discharge rates under 150 spikes/sec, longer latencies of 30 ms, and a narrower dynamic range of approximately 20 dB. An ipsilaterally mediated postsynaptic inhibition tuned specifically to calling song frequencies suppressed low-frequency responses and high frequencies during two-tone stimulation, shaping Int-1's high-frequency tuning.
Why it matters
The findings identify the specific inhibitory mechanism that tunes an auditory interneuron to function as a specialized ultrasound "bat-detector" during flight while filtering out conspecific communication signals.
Limits
The abstract does not state the sample size (number of crickets or recordings). As an insect electrophysiology study, findings represent invertebrate neurobiology and do not translate to vertebrate auditory processing. Measurements were primarily cellular and mechanistic, referencing flight behavior from prior assays rather than testing simultaneous natural predator encounters.
Cited by
- contradicts Crickets possess bimodal auditory neurons with dual sensitivity peaks at 6 kHz and 40 kHz that elicit opposing deterministic behavioral responses.