Morphological and physiological identification of medulla interneurons in the visual system of the tiger beetle larva
- 80 Downloads
The morphology of visual interneurons in the tiger beetle larva was identified after recording their responses. Stained neurons were designated as either medulla or protocerebral neurons according to the location of their cell bodies. Medulla neurons were further subdivided into three groups. Afferent medulla neurons extended processes distally in the medulla neuropil and a single axon to the brain through the optic nerve. They received their main input from stemmata on the ipsilateral side. Two distance-sensitive neurons, near-by sensitive and far-sensitive neurons, were also identified. Atypical medulla neurons extended their neurites distally in the medulla and proximally to the brain, as afferent medulla neurons, but their input patterns and the shapes of their spikes differed from afferent neurons. Protocerebral neurons sent a single axon to the medulla neuropil. They spread collateral branches in the posterior region of the protocerebrum on its way to the medulla neuropil. They received main input from stemmata on the contralateral side. Medulla intrinsic neurons did not extend an axon to the brain, and received either bilateral or contralateral stemmata input only. The input patterns and discharge patterns of medulla neurons are discussed with reference to their morphology.
KeywordsMorphology Physiology Stemmata Tiger beetle larva Visual interneurons
The authors wish to express their thanks to Prof. S.R. Shaw and Prof. I.A. Meinertzhagen (Dalhousie University, Halifax) for their invaluable discussion and correction of the English. This work was supported in part by a Grant-in Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (11694091).
- Bullock TH, Horridge GA (1965) Structure and function in the nervous systems of invertebrates, vol II. Freeman, San FranciscoGoogle Scholar
- Franceschini N, Riehle A, Nestour AL (1989) Directionally selective motion detection by insect neurons. In: Stavenga DG, Hardie RC (eds) Facet of vision. Springer, Berlin Heidelberg New York, pp 360–390Google Scholar
- Friederichs HF (1931) Beiträge zur Morphologie und Physiologie der Sehorgane der Cicindelinen. Z Morphol Oekol Tiere 21:1-172Google Scholar
- Gilbert C (1989) Visual determinants of escape in tiger beetle larvae (Cicindelidae). J Insect Behav 2:557–574Google Scholar
- Mizutani A, Toh Y (1995) Optical and physiological properties of the larval visual system of the tiger beetle, Cicindela chinensis. J Comp Physiol 178:591–599Google Scholar
- Nicholls JG, Martin AR, Wallace BG, Fuchs PA (2001) From neuron to brain, 4th edn. Sinauer, SunderlandGoogle Scholar
- Toh Y, Kuwabara M (1978) Synaptic organization of the fleshfly ocellus. J Neurocytol 4:271–287Google Scholar
- Yamamoto K, Toh Y (1975) The fine structure of the lateral ocellus of the dobsonfly larva. J Morphol 146:415–430Google Scholar