Axonal pathways of the four giant neurons identified in the cerebral ganglia of an african giant snail ( Achatina fulica férussac)

Abstract

1. 1. The axonal pathways of four giant neurons identified in the cerebral ganglia of an African giant snail ( Achatina fulica Férussac) were detected by an intracellular injection of Lucifer yellow. 2. 2. The two giant neurons, d-RCDN (dorsal-right cerebral distinct neuron) and d-LCDN (dorsal-feft cerebral distinct neuron), situated on the dorsal surface of the ganglia, innervated the contralateral cerebro-pleural connectives, indicating that these were the contralaterally descending neurons. 3. 3. The other two giant neurons, v-RCDN (ventral-right cerebral distinct neuron) and v-LCDN (ventral-left) cerebral distinct neuron), found on the ventral surface of the same ganglia, innervated the ipsilateral sublabial nerves and the ipsilateral cerebro-buccal connectives, indicating that these were the ipsilaterally ascending neurons. 4. 4. No fluorescence originating from the naturally occurring catecholamine and indoleamine of the cerebral giant neurons examined was demonstrated by several staining methods. 5. 5. Unidentifiable small neurons containing catecholamine were observed in the cerebral ganglia, whereas the idoleamine components in the ganglia were fewer than those of the suboesophageal ganglia.