The interneurone AN5-AG7 of the duetting bushcricket Ancistrura nigrovittata has its soma in the seventh (penultimate) abdominal ganglion. Its major postsynaptic arborizations with dense thin branches of smooth appearance are found in the prothoracic ganglion. The branches terminate in the auditory neuropile, predominantly at the same location as those auditory receptors that respond best to the female song frequency. Correspondingly, AN5-AG7 responds preferentially to frequencies between 24 and 28 kHz, thereby matching the carrier frequency of the female response song quite well. At frequencies below 24 kHz, AN5-AG7 receives inhibition, which is sometimes seen as clear inhibitory postsynaptic potentials. At these frequencies, thresholds of excitatory postsynaptic potentials are considerably lower than spike thresholds. In contrast, above 20 kHz, the two thresholds match and they correspond to the behavioural threshold. The AN5-AG7 interneurone is more sensitive to soma-contralateral stimuli and it receives predominantly inhibition, but also some excitation, from the soma-ipsilateral ear. Response strength is not greatly affected by stimulus duration but shows prominent habituation. This habituation depends only weakly on intensity and frequency. Some AN5-AG7 interneurones show very small graded potentials and no spiking responses to any acoustic stimuli.

REFERENCES

Brush
J. S.
,
Gian
V. G.
,
Greenfield
D.
(
1985
).
Phonotaxis and aggression in the coneheaded katydid Neoconocephalus affinis
.
Physiol. Ent
10
,
23
–.
Dambach
M.
,
Rausche
H.-G.
,
Wendler
G.
(
1983
).
Proprioceptive feedback influences the calling song of the cricket
.
Naturwissenschaften
70
,
417
–.
Doolan
J. M.
,
Young
D.
(
1989
).
Relative importance of song parameters during flight phonotaxis and courtship in the bladder cicada Cystosoma saundersii
.
J. Exp. Biol
141
,
113
–.
Fielden
A.
(
1960
).
Transmission through the last abdominal ganglion of the dragonfly nymph, Anax imperator
.
J. Exp. Biol
37
,
832
–.
Hedwig
B.
,
Knepper
M.
(
1992
).
NEUROLAB, a comprehensive program for the analysis of neurophysiological and behavioural data
.
J. Neurosci. Meth
45
,
135
–.
Kalmring
K.
(
1975
).
The afferent auditory pathway in the ventral cord of Locusta migratoria (Acrididae). I. Synaptic connectivity and information processing among the auditory neurons of the ventral cord
.
J. Comp. Physiol
104
,
103
–.
Mendenhall
B.
,
Murphey
R. K.
(
1974
).
The morphology of cricket giant interneurons
.
J. Neurobiol
5
,
565
–.
Moiseff
A.
,
Pollack
G.
,
Hoy
R.
(
1978
).
Steering responses of flying crickets to sound and ultrasound: mate attraction and predator avoidance
.
Proc. Natl. Acad. Sci. USA
75
,
4052
–.
Nolen
T. G.
,
Hoy
R. R.
(
1984
).
Initiation of behavior by singleneurons: The role of behavioral context
.
Science
226
,
992
–.
Pfluger
H.-J.
,
Bräunig
P.
,
Hustert
R.
(
1988
).
The organisation of mechanosensory neuropiles in locust thoracic ganglia
.
Phil. Trans. R. Soc. Lond. B
321
,
1
–.
Stumpner
A.
(
1996
).
Tonotopic organization of the hearing organ in a bushcricket — Physiological characterization and complete staining of auditory receptor cells
.
Naturwissenschaften
83
,
81
–.
Stumpner
A.
(
1997
).
An auditory interneurone tuned to the male song frequency in the duetting bushcricket Ancistrura nigrovittata (Orthoptera, Phaneropteridae)
.
J. Exp. Biol
200
,
1089
–.
Stumpner
A.
(
1998
).
Picrotoxin eliminates frequency selectivity of an auditory interneuron in a bushcricket
.
J. Neurophysiol
79
,
2408
–.
Wohlers
D. W.
,
Huber
F.
(
1985
).
Topographical organization of the auditory pathway within the prothoracic ganglion of the cricket Gryllus campestris L
.
Cell Tissue Res
239
,
555
–.
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