Deutocerebrum

Axons of antennal ORCs project through the antennal nerve to enter the brain at the level of the ipsilateral antennal lobe (AL) of the deutocerebrum (52). ORC axons project from the flagellum to targets in the AL, but axons from antennal mechanosensory neurons bypass the AL and project instead to an "antennal mechanosensory and motor center" in the deutocerebrum posteroventral (with respect to the body axis of the animal) to the AL (52, 58, 64). In moths and certain other insect groups, sex-pheromonal information is processed in a prominent male-specific neuropil structure in each AL called the macroglomerular complex (MGC) (16, 52, 64, 65). 

When the antennae are completely ablated, the male cockroach still responds to the sex pheromone (Roth and Willis, 1952). This suggests that some pheromone-responsive cells are also located elsewhere, such as on the mouthparts. Olfactory receptor cells on the palps of P. americana project to the lobus glomeratus within the posterior region of the ventral deutocerebrum (Boeckh and Ernst, 1987). However, it is not known whether pheromone-responsive cells on the palps project to the more anterior macroglomerulus. 

Hosl, M. (1990). Pheromone-sensitive neurons in the deutocerebrum of Periplaneta americana receptive fields on the antenna. Journal of Comparative Physiology A 167 321-327. 

Boeckh I. and Boeckh V. (1979) Threshold and odor specificity of pheromone-sensitive neurons in the deutocerebrum of Antheraea pemyi and A. polyphemus (Saturnidae). J. Comp. Physiol. 132, 235-242. 

The primary olfactory center of insects, the AL, is a sphere-shaped part of the deutocerebrum that receives sensory input from ORNs present on antennae and mouthparts (Figure 24.1 A). The AL consists of spheroidal neuropilar structures, glomeruli, where synaptic contacts between ORN axons and AL interneurons take place. In most insect species the AL contains 40 to 160 glomeruli arranged... 

Fig. 7.8 Dendritic arborizations and electrical responses to odors of similar classes of multiglomerular local intemeurons in the deutocerebrum of P. argus (a, c) and P. clarkii (b, d). Note that in both crustaceans the dendrites invest both the OL and LAN, and both respond not only to odorants but also to the onset of hydrodynamic flow past the antennular flagellum, (a, c) from Schmidt and Ache 1996b (b) from Mellon and Alones 1995 (d) from Mellon and Humphrey 2007...

Mellon D (2005) Integration of hydrodynamic and odorant inputs by local intemeurons of the crayfish deutocerebrum. J Exp Biol 208 3711-3720... 

Mellon D, Humphrey JAC (2007) Directional asymmetry in responses of local intemeurons in the crayfish deutocerebrum to hydrodynamic stimulation of the lateral antennular flagellum. J Exp Biol 210 2961-2968... 

Sullivan JM, Beltz BS (2001) Neural pathways connecting the deutocerebrum and lateral protocerebrum in the brains of decapod crustaceans. J Comp Neurol 441 9-22... 

Fig. 8.7 Comparison of the olfactory deutocerebrum in a marine vs. a terrestrial isopod (Harzsch et al., unpublished data), (a) The head of Idotea baltica (Isopoda, Valvifera) with the pair of large second antennae and the pair of smaller first antennae in-between. Inset shows higher magnification of a first antenna. Synapsin-immunoreactivity (al) and the localization of Rfamide-like immunoreactivity (a2) shows the presence of a distinct OL composed of spherical glomeruli. The tritocerebrum (TC) receives the afferents from the second antennae and the protocerebrum (PC) receives highly processed visual input, (b) The head of the desert isopod Hemilepistus reaumuri with a pair of conspicuous second antennae. The inset shows the minute first antennae. Synapsin-immunoreactivity (bl) and the localization of Rfamide-like immunoreactivity (b2) shows that an OL is not present (arrow ). Scale bars 100 pm...

Boeckh, J. (1974) Die Reaktionen olfactorischer Neurone im Deutocerebrum von Insekten im Vergleich zu den Antwortmustern der Geruchssinneszellen. /. comp. Physiol., 90, 183-205. 

Chambille, I. and Masson, C. (1980) The deutocerebrum of the cockroach Blaberus Cranifer Burm. Spatial organization of the sensory glomeruli. J. Neurobiol., 11, 135-57. 

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