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

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.