A New Approach to Modeling Morphogenesis Using Control Theory

It has been proposed that biological structures termed fractones may govern morphogenic events of cells; that is, fractones may dictate when a cell undergoes mitosis by capturing and concentrating certain chemical growth factors created by cells in their immediate vicinity. Based on this hypothesis, we present a model of cellular growth that incorporates these fractones, freely-diffusing growth factor, their interaction with each other, and their effect on cellular mitosis. The question of how complex biological cell structures arise from single cells during development can now be posed in terms of a mathematical control problem in which the activation and deactivation of fractones determines how a cellular mass forms. Stated in this fashion, several new questions in the field of control theory emerge. We present this new class of problems, as well as an initial analysis of some of these questions. Also, we indicate an extension of the proposed control method to layout optimization.

Alteration of Neural Development In the Brain of Adult BTBR T+ tf/J Mice, an Animal Model for Autism

Autism is a growing spectrum of social impairment disorders resulting from neurological abnormalities and is characterized by symptoms of impaired social, communication skills and motor defects. It seems to result from distorted neural development. Under the supervision of Dr. Frederic Mercier, this research project aimed to characterize the potential alterations of connective tissue structures in the brain of the mutant BTBR T+ tf/J mouse, a model of autism. We have described anatomical alterations of the meninges, vasculature and fractones, the specialized extracellular matrix (ECM) of the subventricular zone, in the forebrain and midbrain of adult BTBR T+ tf/J mice by comparison with B6 control mice. We used Immunofluorescence histochemistry for laminin, a major ECM marker, on series of coronal sections of adult BTBR T+ tf/J and B6 brains. We used bisbenzidine cell nucleus staining and N-sulfated heparan sulfate proteoglycans (NS-HSPG) to further characterize series of brain sections containing the amygdala and hippocampus. The results showed significant defects in the connective tissue (meninges) and ECM throughout the series of sections examined. In the brain of BTBR T+ tf/J mice, the volume of lateral ventricles was significantly reduced, the falx cerebri (a meningeal projection that separated the brain into two hemispheres) was elongated, the arteries bloated and the choroid plexus atrophied. Moreover, fractone numbers in BTBR T+ tf/J mice were smaller in the SVZ of the anterior portion of the lateral ventricles than that of wild type mice