Deutocerebrum of the cockroach Blaberus craniifer burm. Quantitative study and automated identification of the glomeruli

Abstract

The glomerular organization of the hemideutocerebrum is analyzed quantitatively, using only spatial position, in four individuals (eight hDTCs) after a visual identification of glomeruli on graphic reconstructions. In order to assess directly the invariance of the neuropil in an insect brain the following is done: (1) The position of each glomerulus is compared to the position A' it should occupy if the hDTCs were identical. It is shown that in 80 and 71% of the cases, respectively, intra- and interindividual comparisons in the studied glomerulus is the nearest to A'. (2) The actual position is equally compared to the theoretical location A" each glomerulus should occupy if its absolute position could be changed but not its relative position with respect to its neighbors. The calculation of A" is based on process (3). In 86 and 80% of the cases, respectively, it is found that the actual position is that which is nearest to A". (3) An automated identification process, based on absolute and relative locations, but completely independent of visual identification, is described. It allows the identification of 77 and 74% of glomeruli, respectively. These matchings are in 96 and 90% of the cases identical to the visual matchings. The location predictability of most glomeruli is discussed to show the existence, nature, and limits of the hemideutocerebral invariance.

Complete mapping of glomeruli based on sensory nerve branching pattern in the primary olfactory center of the cockroach Periplaneta americana

“…In previous attempts to identify all glomeruli in insects, glomeruli were identified on the basis of their shapes, sizes, and positions relative to some landmark glomeruli (Rospars and Chambille, 1981;Flanagan and Mercer, 1989;Rospars and Hildebrand, 1992;Galizia et al, 1999;Laissue et al, 1999;Couton et al, 2009;Kazawa et al, 2009;Varela et al, 2009). However, these indices sometimes vary between individuals .…”

“…mayri (Kelber et al, 2009). The smaller numbers of glomeruli in insects have allowed morphological identification of all glomeruli among different individuals (Rospars and Chambille, 1981;Rospars and Hildebrand, 1992;Galizia et al, 1999;Laissue et al, 1999;Kazawa et al, 2009;Couton et al, 2009;Varela et al, 2009). There is, however, some ambiguity in identifying glomeruli solely by their size, shape, and position, because these may vary among individuals.…”

Projection neurons originating from thermo‐ and hygrosensory glomeruli in the antennal lobe of the cockroach

“…However, elongated glomeruli that are morphologically reminiscent of DC1 or DC2 glomeruli have been observed in the dorsal part of the antennal lobe in the cockroach, Blaberus craniifer (Rospars and Chambille, 1981), and in several Orthoptera species (Ignell et al, 2001). Some PNs that have projection patterns very similar to those of DC1PNs have been reported in the sphinx moth (Homberg et al, 1988).…”

Central projections of the antennal cold receptor neurons and hygroreceptor neurons of the cockroach Periplaneta americana

“…There are intensive physiological and morphological studies on those interneuions in cockroaches and moths (Waldow, 1977;Boeckh and Boeckh, 1979;Matsumoto and Hildebrand, 1981;Burrows et al, 1982;Schaller-Selzer, 1984;Kanzaki and Shibuya, 1986;Christensen and Hildebrand, 1987b;Kanzaki et al, 1989;Hod, 1990;Christensen et al, 1991;Hansson et al, 1991). Neuroanatomical approaches to the antennocerebral pathways and to the glomerular architecture of the antennal lobe have also improved the comprehensive understanding of the antennal sensory system of insects (Chambille et al, 1980;Rospars and Chambille, 1981;Prillinger, 1981;Arnold et al, 1985;Homberg et al, 1988;Rospars and Hildebrand, 1992;Malun et al, 1993).…”