The deutocerebrum of the cockroach Blaberus craniifer Burm. Spatial organization of the sensory glomeruli.

The objective of this work is to describe the glomerular organization of the deutocerebrum in Blaberus craniifer and to test the hypothesis that the glomeruli are identifiable. The problem is studied using the techniques of analytical geometry, i.e., by measuring the location of the glomeruli in cartesian coordinate systems. Computerized geometrical and statistical techniques are described for the three-dimensional reconstruction and quantitative study of these brain structures. The invariance of the glomerular organization, and consequently the identifiability of the glomeruli, is based on three criteria: (1) the number of glomeruli per hemideutocerebrum (hDTC) is a constant (109); (2) the position of the glomeruli is symmetrical in the two sides of one individual and identical in the same side of two individuals, except for small local variations,(3) the dimensions of two positionally homologous glomeruli are statistically equal in the same and in different individuals, except for a macroglomerulus which is found only in the male. The causes of variability, from experimental and biological origin, are discussed and quantitatively evaluated. The interindividual biological variability, not ascribable to differences in size between brains, expressed as a 95% interval, is estimated to be 27 micrometer for the location of glomeruli and 12 micrometer for the diamter of glomeruli.