Excitatory influence of wind-sensitive local interneurons on an ascending interneuron in the cricket cercal sensory system.
This study examined the effects of a set of identified wind-sensitive local interneurons (9DL interneurons) on the wind-evoked spike output and directional sensitivity of an ascending interneuron (10-3) in the cricket (Acheta domesticus) cercal sensory system. Comparison of the directional sensitivities of the 9DL interneurons and 10-3 revealed that 3 of the 9DL interneurons have a large degree of overlap in their excitatory receptive fields with that of 10-3. Photoinactivation of any one of these 3 9DL interneurons resulted in a significant decrease in the spike output of 10-3 at its optimal excitatory wind stimulus positions. However, the overall directional sensitivity of 10-3 remained essentially unchanged. Photoinactivation of the one 9DL interneuron which had no overlap in its excitatory receptive field with 10-3 did not affect 10-3's responsiveness to wind stimuli. Results from simultaneous intracellular recordings of 10-3 and one of the 9DL interneurons which had an excitatory influence on 10-3 showed that depolarization of the local interneuron produced an epsp in 10-3, and could elicit several action potentials. Comparison of the morphologies of the 9DL interneurons and 10-3 revealed that the 3 9DL interneurons which had an excitatory influence on 10-3 all had regions of dendritic overlap with this ascending interneuron.
Bodnar
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DA
Department of Molecular and Cell Biology, University of California, Berkeley.
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003712:Dendrites / Q000502:physiology; D005260:Female; D005724:Ganglia / Q000166:cytology; D006135:Gryllidae / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D007478:Iontophoresis; D008027:Light; D009949:Orientation / Q000502:physiology; D012679:Sense Organs / Q000033:anatomy & histology / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D014919:Wind