Neuroanatomy of the Vestimentiferan Tubeworm Lamellibrachia satsuma Provides Insights into the Evolution of the Polychaete Nervous System
Figure 2
Brain and ventral nerve cord of the tentacular and vestimental regions in L. satsuma.
A–C: Z-projection images of anti-SYNORF1 and anti-serotonin immunoreactivities showing Anti-SYNORF1 positive neuropils and serotonergic neurons of the brain and the ventral nerve cord. D–F: Z-projection images of anti-SYNORF1 and anti-serotonin immunoreactivities at the anterior end of the central nervous system. A pair of prominent neuropils is connected through the anterior (arrows) and posterior (arrowheads) connectives. G–I: Three-dimensional reconstructions of the central nervous system. Ventrolateral view (G) and dorsolateral view (H) views show that anti-SYNORF1 positive neuropils in the brain are thickened dorsally. Serotonergic neurons are located on the ventral and lateral sides of the anti-SYNORF1 positive neuropils. I: Dorsal view of the brain: anterior is up. The anterior (arrows) and posterior (arrowheads) anti-SYNORF1 positive signals connect a pair of neuropils. J, K: Expression patterns of elav (J) and syt (K) showing the distribution of neural cell bodies. L: Section through the posterior end of the brain neuropils. Dorsal is up. Double stain of syt (brown) and elav (yellow) shows the overlapped expression patterns of these neuron marker genes. The neuropils are encapsulated by neurons. M−O: Cross sections of brain. Positions are shown in D. The cell bodies cover the neuropils. Scale bars: 100 µm. br, brain; vcf, ventral ciliated field.