Dynamics of neuropithelial cell proliferation in the developing chick optic tectum.

RAPACIOLI M; ORTALLI AL,; RODRIGUEZ-LIMARDO R; SÁNCHEZ V; SCICOLONE G; MAZZEO J; FLORES V.

Buenos Aires

Congreso; XII Congreso Latinoamericano y 1ro IberoAmericano de Cs Fisiológicas.; 2006

Asociacion Latinoamericana de Ciencias Fisiologicas y Sociedad Argentina de Fisiologia.

Dynamics of neuropithelial cell proliferation in the developing chick optic tectum.   M. Rapacioli, A. Ortalli, R. Rodriguez, V. Sánchez, G. Scicolone, J. Mazzeo, V. Flores. Interdisc. Group in Theoretical Biology; Favaloro University - Lab. Developmental Neurobiology, Inst. Cell Biol. and Neurosci. “Prof. E. de Robertis”; UBA. Argentina. The developing chick optic tectum (OT) is used as experimental model to analyze the spatial/temporal organization of the proliferative activity. Analyses of variability of proliferation were performed as a function of two intrinsic spatial axes (cephalic-caudal and dorsal-ventral) during the entire proliferative period. Spatial coordinates of every mitotic cell were recorded on histological sections obtained from OT of different developmental stages. Several space signals representative of the proliferative process were constructed in order to apply conventional statistical methods (ANOVA test and Kruskall-Wallis), spectral analysis (Power Spectral Density) and non-linear methods (Fano Factor, Allan Factor, Detrended Fluctuation Analysis) that allow dynamics characterization and scaling coefficient estimation. Results indicate that a) the proliferation dynamics significantly changes as a function of the developmental stage; b) at the time of maximal activity the dynamics corresponds to a non-stationary process; c) it can be described as comprising deterministic and stochastic components; d) the deterministic component can be described as a global trend; e) the second one corresponds to a stochastic process whose values of scaling coefficients are indicative of the existence of local correlation. These results can be interpreted as manifestation of the operation of a) a long-range developmental influence that installs space-dependent differences on the whole neuroepithelial cell population along the cephalic-caudal axis and b) short-range interactions among proliferating cells leading to clusterization and a non-uniform spatial distribution. These theoretical analyses interpreted together with 2D and 3D representations of the proliferative activity indicate the existence of a defined area of the tectal hemisphere (“proliferation region”) of maximal activity that characteristically moves towards the caudal end as development progresses. Supported by grants from CONICET (Argentina)