Olfactory Centers in the Brain of Freshwater Crayfish
Axons of the olfactory receptor neurons in crustaceans such as freshwater crayfish terminate ipsilaterally within the brain in an olfactory lobe, where they synapse with local interneurons and also with projection neurons that course to the lateral protocerebrum in the eyecups. A subset of local interneurons transmits olfactory information to a large accessory lobe, just caudal to the olfactory lobe. The accessory lobe remains enigmatic; it is an apparent target of sensory interneurons not only from the olfactory lobes but also from visual centers in the brain and from the tactile processing centers of the tritocerebrum. Furthermore, like the olfactory lobe, the accessory lobe is invested with the arborized terminals of neighboring giant serotonergic neurons. A massive projection from the accessory lobe ascends the lateral protocerebral tract, where it generates a strong inhibitory influence upon synchronized oscillatory neurons within the hemiellipsoid bodies. The output of these lateral protocerebral neurons is multimodal, both in the sense that they are excited by multiple sensory systems, but also in the sense that their output is modulated by inhibition from the accessory lobes.
KeywordsSugar HPLC Ethyl Cadmium Glycine
Unable to display preview. Download preview PDF.
- Bauer U, Hatt H (1980) Demonstration of three different types of chemosensitive units in the crayfish claw using a computerized evaluation. Neurosci Lett 17:208–214Google Scholar
- Harzsch S, Schmidt M (1996) Brain development in adult crayfish includes the generation of new deutocerebral neurons. Proc Ger Zool Soc 89:1–50Google Scholar
- Helluy S, Beltz B (1990) Stages in the development of the American lobster with special emphasis on its nervous system. In: Frontiers in crustacean neurobiology. Wiese K, Krenz W-D, Tautz J, Reichert H, Mulloney B (eds). Birkhäuser, Basel, pp530–536Google Scholar
- Mellon DeF, Sandeman DC, Sandeman RE (1992b) Characterization of oscillatory olfactory interneurones in the protocerebrum of the crayfish. J Exp Biol 167:15–38Google Scholar
- Meunpol O, Sandeman R, Sandeman D, Kapoor V (1996) Stimulus-coupled serotonin release from crayfish accessory lobes Cherax destructor. Abstr 13th Annu Meet of ANZ Soc Comp Phys Biochem 56. Melbourne, Australia, 1996Google Scholar
- Tsvileneva VA, Titova VA (1985) On the brain structures of decapods. Zool Jahrb Anat 113:217–266Google Scholar
- Wachowiak M, Diebel CE, Ache BW (1996) Functional organization of olfactory processing in the accessory lobe of the spiny lobster. J Comp Neurol 178:211–226Google Scholar
- Zhainazarov AB, Wachowiak M, Boettcher A, Elenes S, Ache BW(1997) lonotropic GABA receptor from lobster olfactory projection neurons. J Neurophysiol 76:2235–2251Google Scholar