New Insights on the Olfactory Lobe of Decapod Crustaceans

Abstract

Studies on the crustacean nervous system have been responsible for advances in neuroscience and continue to play an important role in comparative neurobiology. The organization of crustacean brains provides clues about their phylogeny and might also offer some hints regarding their lifestyles. In this study, we compared the organization of specific brain regions of three species of marine shrimp with two species of freshwater prawns, making possible the identification of a pathway issuing from the periphery and cluster 9, which was not previously identified in freshwater prawns and shrimp. Although the brains of the species studied show the same general organization of other crustaceans, variations in the structural organization of the olfactory lobe, evidenced by different immuno-markers, were observed between shrimp species and prawns. In contrast to shrimp, the more well-defined organization of the olfactory lobe in freshwater prawns might reflect greater integration in the processing of olfactory information. Also, in freshwater prawns we described fibers organized as a tract similar to the deutocerebral commissure.

On the Brain of a Crustacean: A Morphological Analysis of CaMKII Expression and Its Relation to Sensory and Motor Pathways

“…Immunohistochemistry revealing CaMKII showed intense labeling of a bundle of fibers within the protocerebral bridge, central body, and protocerebral tracts in the anterior medial protocerebrum and in the posterior medial protocerebrum. In the deutocerebrum, an intense CaMKII immunoreaction was observed in the olfactory-globular tract (OGT) and in the prospective deutocerebral commissure, as also observed by [19] (Figure 2B). The immune reaction using the FMRFamide antibody showed labeled cells in the cell clusters 6, 8, 9, and 11.…”

“…In general, the visual sensory stimuli are converted into motor responses and eventually translated into behaviors [38]. In a previous report, we demonstrated in freshwater prawns and marine shrimps that the OL is responsible for converting sensory stimuli into motor information [19]. Here, we showed that CaMKII is expressed in the same sites as FMRFamide (which was previously used to control for the labeling of neuronal elements in crustaceans [24], [25]) and one postsynaptic glutamate receptor in the sensory structures.…”

“…The basic functions of the crustacean brain are concerned with the activity of the photoreceptive cells located in the compound eyes, linked to the protocerebrum, and also with the activity of the chemoreceptive and mechanoreceptive sensilla located on the antennules and antennas, linked to the deutocerebrum and tritocerebrum respectively [20], [21], [22]. In a previous study [19], we reported subtle differences in the brain microanatomy of freshwater prawns and marine shrimps, mainly in the olfactory lobes (OL). In the present study, we examined the in situ expression of CaMKII, and its relationship to other neurotransmitters or neuromodulators, in the eyestalk and in the brain of the freshwater prawn Macrobrachium acanthurus, in order to expand knowledge of the interaction of sensory and motor inputs in invertebrates.…”

“…Anatomically, the crustacean brain is constituted by the fusion of the first three ganglia of the ventral nerve cord: the protocerebrum in the anterior region of the brain, the deutocerebrum in the middle region, and the tritocerebrum in the posterior region [17], [18], [19]. The basic functions of the crustacean brain are concerned with the activity of the photoreceptive cells located in the compound eyes, linked to the protocerebrum, and also with the activity of the chemoreceptive and mechanoreceptive sensilla located on the antennules and antennas, linked to the deutocerebrum and tritocerebrum respectively [20], [21], [22].…”

Treatise on Zoology - Anatomy, Taxonomy, Biology. The Crustacea, Volume 9 Part A

“…The two arms of OGTs touch each other medially forming a characteristic chiasma located next to the central body (Fanenbruck et al, 2004). However, the caudal-rostral organization of the median protocerebrum into the anterior median and posterior median protocerebral neuropiles is still discernible (Ammar et al, 2008). The protocerebral bridge and the central body are clearly delineated, as are the paired OLs, the lateral antennule neuropil and the median antennule neuropil (Ammar et al, 2008).…”