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.
KeywordsProjection Neuron Local Field Potential Compound Action Potential Spiny Lobster Olfactory Receptor Neuron
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