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Polarization-sensitive neurons in the central complex of crickets - how does the CNS code orientation?
406
Abstracts
putative transmitter of the sensory-to-interneuron synapses in the cercal sensory system. Then, NO signaling in TAG is suggested to be involved with processing of wind sensory information. From above, there are two different effect of NO production in the nervous system; NO as ʻʻhomeostatic factor" and ʻʻreinforcer of sensory input signal to induce higher function."
of a group of polarization-sensitive neurons, so-called ʻʻcompass neurons". Each neuron of this group is narrowly tuned to specific e-vector orientations, i.e. each body orientation relative to the polarization pattern of the sky is represented as a specific response pattern of ʻʻcompass neurons". doi:10.1016/j.cbpb.2006.10.018
doi:10.1016/j.cbpb.2006.10.017
SB6 SB5 Polarization-sensitive neurons in the central complex of crickets - how does the CNS code orientation? a
b
a
a
Midori Sakura , Dimitrios Lambrinos , Thomas Labhart , Dept. Zoology, Univ. Zurich, CH-8057 Zurich, Switzerland; bDept. Computer Science, Univ. Zurich, CH-8057 Zurich, Switzerland It is well known that many insects can detect the polarization pattern of the sky and use it as a sensory cue for navigation. Although both, the sensory mechanisms of polarization vision and navigation behavior have already been studied to some detail in several species, the central neural circuits that evaluate the sensory data and control motor output remain largely unknown. In crickets, sensory information on polarized light is integrated in the optic lobe. Polarization-sensitive neurons of the optic lobe are tuned to only three e-vector orientations of polarized light. It is still unclear how the brain codes the exact e-vector orientation by using only these three evector signals. In this study, we (1) constructed a possible neural model that codes exact e-vector orientations from these three signals. (2) We electrophysiologically recorded neural responses to polarized light in the central complex. The results of both, the model and the recording, suggest the existence
Temperature entrainment of circadian locomotor rhythm in cricket (Gryllus bimaculatus) after removal of optic lobes Svetlana Karpova, Kenji K. Tomioka, Grad. Sch. Nat. Sci. Tech., Okayama Univ., Okayama 700-8530, Japan The effects of various temperature cycles on the locomotor activity of the cricket Gryllus bimaculatus were investigated after bilateral ablation of the optic lobes, which are the site of main circadian oscillators. Lobeless animals were arrhythmic in constant temperature and photoperiod, but showed rhythmicity under temperature cycles, with increasing activity during warm phase. The rhythms were exhibited under cycles of different periods, indicating that the rhythm was driven mainly by a direct response to temperature changes. However, after synchronization to temperature cycles of 24-h periodicity, lobeless crickets showed residual rhythmicity for a few days after transfer to constant temperature. The results suggest that the locomotor activity in lobeless animals is controlled by a weak oscillator located outside of the optic lobes, that can be forced to oscillate by cycles of temperature. doi:10.1016/j.cbpb.2006.10.019
Abstracts
putative transmitter of the sensory-to-interneuron synapses in the cercal sensory system. Then, NO signaling in TAG is suggested to be involved with processing of wind sensory information. From above, there are two different effect of NO production in the nervous system; NO as ʻʻhomeostatic factor" and ʻʻreinforcer of sensory input signal to induce higher function."
of a group of polarization-sensitive neurons, so-called ʻʻcompass neurons". Each neuron of this group is narrowly tuned to specific e-vector orientations, i.e. each body orientation relative to the polarization pattern of the sky is represented as a specific response pattern of ʻʻcompass neurons". doi:10.1016/j.cbpb.2006.10.018
doi:10.1016/j.cbpb.2006.10.017
SB6 SB5 Polarization-sensitive neurons in the central complex of crickets - how does the CNS code orientation? a
b
a
a
Midori Sakura , Dimitrios Lambrinos , Thomas Labhart , Dept. Zoology, Univ. Zurich, CH-8057 Zurich, Switzerland; bDept. Computer Science, Univ. Zurich, CH-8057 Zurich, Switzerland It is well known that many insects can detect the polarization pattern of the sky and use it as a sensory cue for navigation. Although both, the sensory mechanisms of polarization vision and navigation behavior have already been studied to some detail in several species, the central neural circuits that evaluate the sensory data and control motor output remain largely unknown. In crickets, sensory information on polarized light is integrated in the optic lobe. Polarization-sensitive neurons of the optic lobe are tuned to only three e-vector orientations of polarized light. It is still unclear how the brain codes the exact e-vector orientation by using only these three evector signals. In this study, we (1) constructed a possible neural model that codes exact e-vector orientations from these three signals. (2) We electrophysiologically recorded neural responses to polarized light in the central complex. The results of both, the model and the recording, suggest the existence
Temperature entrainment of circadian locomotor rhythm in cricket (Gryllus bimaculatus) after removal of optic lobes Svetlana Karpova, Kenji K. Tomioka, Grad. Sch. Nat. Sci. Tech., Okayama Univ., Okayama 700-8530, Japan The effects of various temperature cycles on the locomotor activity of the cricket Gryllus bimaculatus were investigated after bilateral ablation of the optic lobes, which are the site of main circadian oscillators. Lobeless animals were arrhythmic in constant temperature and photoperiod, but showed rhythmicity under temperature cycles, with increasing activity during warm phase. The rhythms were exhibited under cycles of different periods, indicating that the rhythm was driven mainly by a direct response to temperature changes. However, after synchronization to temperature cycles of 24-h periodicity, lobeless crickets showed residual rhythmicity for a few days after transfer to constant temperature. The results suggest that the locomotor activity in lobeless animals is controlled by a weak oscillator located outside of the optic lobes, that can be forced to oscillate by cycles of temperature. doi:10.1016/j.cbpb.2006.10.019