aspersa as a source of procerebral neurons, persist in adult Helix (Bang, 1917; Bullock and Horridge, 1965; Zs.-Nagy and Sakharov, 1970).
aspersa indicate that the size of procerebral neurons remains constant throughout the life of the snail.
Later, when snail weight is better approximated by the logistic equation, cells that are contiguous with neurons in the procerebral apex are seen in the peritentacular and olfactory nerves.
The procerebral area containing neurons could be recognized in each frame by the fluorescence of the densely packed neuronal nuclei (supplemental video 1 available at http://www.biobull.org/content/supplemental/).
It is typical for antibodies to SCP, TPep, and FMRFamide that there is no immunoreactivity at the procerebral apex where neurons are being added (Fig.
Neuron-free cavities in the procerebral apex connect with the cerebral tube (Fig.
The number of mitotic cells in the cerebral tube is greater near the procerebral apex (Fig.
Cells from the peritentacular nerve appear to migrate directly into the procerebral apex (Fig.
As shown by the close packing of procerebral nuclei, the nuclei represent a large part of the neuronal volume in the pmcerebrum (Fig.
The number N of procerebral neurons of both laboratory-raised and field-collected snails is a linear function of the logarithm of their weight,
Cells in the peritentacular nerve merge with the apex of the procerebrum when growth at the procerebral apex begins to accelerate at about 40 days post-hatch.
Dopamine is known to modulate the activity of procerebral
olfactory intemeurons in the pulmonate mollusc Limax maximus (Gelperin et al., 1993) as well as several aspects of central olfactory processing in amphibians and mammals (Duchamp-Viret et al., 1997; Doty et al., 1998).