Simultaneous extracellular recordings from both locust abdominal connective
s show a differential activation of both bilateral homologues of an identif
ied long projection interneuron (A4I1) in response to wind stimuli from dif
ferent directions. Despite the previously shown extensive structural dynami
cs of sensory afferents and synaptic rearrangement of the direct afferent-t
o-interneuron connections during postembryonic development, a directional s
ensitivity is already present in first instar nymphs. Only quantitative cha
nges in the strength of the directional response can be detected. Intracell
ular stainings of the A4I1 interneuron in first instar nymphs and adults sh
ow that general morphological features do not change during postembryonic d
evelopment, in contrast to the presynaptic sensory afferents. This also hol
ds for general morphological features of pleuroaxillary flight motoneurons.
The output connections of A4I1 to these motoneurons and an unidentified in
tersegmental interneuron are already present in flightless nymphs. (C) 2000
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