Peripheral interaction in the tympanic organ of a moth

1983 ◽  
Vol 70 (2) ◽  
pp. 99-100 ◽  
Author(s):  
F. Coro ◽  
M. P�rez
1961 ◽  
Vol 38 (3) ◽  
pp. 545-558 ◽  
Author(s):  
NOBUO SUGA ◽  
YASUJI KATSUKI

1. The impulses from the tympanic organ are transmitted at the prothoracic ganglion to a central neuron, the auditory T large fibre, which lies in the cord between the brain and the metathoracic ganglion. The impulses in the T large fibre are conducted rostrally and caudally with the same discharge pattern. Information is sent up to the brain, and down to the metathoracic ganglion, after a delay of about 12 msec. 2. The impulses from the cercal hair sensilla are transmitted to two similar auditory C large fibres which lie in the cord between the metathoracic and last (6th) abdominal ganglia and are then sent up to the mesothoracic ganglia by other auditory large fibres. 3. Central inhibitory interaction between the impulses from the tympanic nerves of the two sides are shown by a marked increase of impulses in the T large fibre following section of one of the tympanic nerves. No inhibitory interaction is found between the impulses from the two cercal nerves. 4. The auditory T large fibre receives not only the excitatory effect from the ipsilateral tympanic nerve at the prothoracic ganglion, but also the inhibitory and weak excitatory effects from the contralateral one. 5. The response range of the T large fibre is narrower than the threshold curve of the tympanic nerve and corresponds with one type of response range in the tympanic neurons. The response ranges of the C large fibres correspond closely with the threshold curve of the cercal nerve. 6. A large difference in threshold between the two T large fibres is found in the response to sound incident from the side. The number of impulses in the T large fibre nearer to the sound source is greater than in that farther from the source. 7. The difference in the number of impulses between the two T large fibres is most marked in the response to sound of the frequency which is dominant in stridulation. This difference is due to the mutual inhibitory interaction of neurons which modifies the number of impulses without changing the threshold of the tympanic large fibre. 8. It is suggested that the central inhibitory interaction increases the information about a sound source and plays an important role in the mechanism of the directional sense. 9. The stridulation of the group activates the tympanic nerve and evokes synchronized discharge in the T large fibre, but scarcely at all in the primary C large fibre. The tympanic organ and its neural network seem well adapted to reception of stridulation. 10. It is concluded that though neither of the two sound receptive organs--the tympanic organ and the cercal hair sensilla--can perform frequency analysis, the insect may be able to do so by making use of both organs, since they have different frequency ranges and are served by different auditory large-fibre tracts.


1998 ◽  
Vol 201 (24) ◽  
pp. 3419-3424 ◽  
Author(s):  
J. H. Fullard ◽  
E. Forrest ◽  
A. Surlykke

It has been proposed that the most sensitive auditory receptor cell (A1)in the two-celled ears of certain noctuoid moths is inhibited by its partner, the A2 cell, at high stimulus intensities. We used the single-celled ears of notodontid moths, also noctuoids, to test this hypothesis. The A1 cells of all but one of the moths tested exhibited non-monotonic firing rates, with reduced firing rates at high stimulus intensities and showing no relationship to the firing rate of the only other receptor, the non-auditory B cell. These results challenge the peripheral interaction hypothesis for A1 firing patterns in two-celled moth ears. An examination of notodontid A1 adaptation rates and laser vibrometry results suggests that receptor adaptation and tympanal motion non-linearity are more likely explanations for the non-monotonic receptor firing observed in both single- and multi-celled moth ears.


1957 ◽  
Vol 134 (1) ◽  
pp. 127-157 ◽  
Author(s):  
Kenneth D. Roeder ◽  
Asher E. Treat
Keyword(s):  

1973 ◽  
Vol 51 (7) ◽  
pp. 681-685 ◽  
Author(s):  
K. D. Roeder ◽  
M. B. Fenton

Adult Scoliopteryx libatrix L. overwinter in the entrance areas of caves and mines in Ontario, which also harbor hibernating bats. The tympanic organs of S. libatrix taken from hibernation and tested at room temperature were found to be sensitive to ultrasound between 20 and 40 kHz, which overlaps with the frequencies used by the bats with which it shares hibernacula. The sensitivity of the tympanic organ and the connector neurons in the protocerebrum is +5–10 decibels (dB) greater than those of other noctuid moths for which data are available. In spite of the auditory detection of ultrasonic pulses and transmission of the resultant stimuli to the protocerebrum, S. libatrix in stationary flight showed no avoidance response to a source of ultrasonic pulses. This behavior is markedly different from that of some other noctuid moths tested during their activity periods. The significance of the absence of a behavioral response in the moths is discussed in relation to the activity of bats around the caves and mines.


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