invites you to a


to be presented by

Professor Michael Reed


The lectures will be held in

Room 001

Physics Building


Technion - Israel Institute of Technology
Haifa, Israel

Lecture I:  Monday 7 November, 2005 at 15:30

Room 001, Physics Building


Probability and Neurobiology


Neurons are inherently variable devices and therefore an important general question in the study of the central nervous system is how we can make accurate calculations with (large numbers of) imperfect devices. This question is particularly pertinent in the auditory system where behavioral studies show that mammals can detect extremely small time differences. After a brief introduction to the auditory system, experimental data will be presented that show that the question is serious indeed. A natural abstraction of the question leads to a (not so simple) problem in probability theory for which analytical and computational results (with Colleen Mitchell) will be presented. Recent theoretical results suggest that the behavior of some real neurons is similar to the behavior of the abstract neurons. Experiments are currently underway to see if this is true.

Lecture II:  Wednesday, 9 November, 2005  at 15:30

Room 001, Physics Building


Cell Metabolism, Mathematics, and Public Health


Folate and methionine metabolism, a small part of cell biochemistry, is crucial for cell replication and DNA methylation. There is mounting evidence that the mechanisms by which some gene polymorphisms or dietary deficiencies are statistically linked to heart disease and certain cancers involve disruptions of folate and methionine metabolism. Folate metabolism is also the target of several chemotheraputic agents and some antibiotics target folate metabolism in bacteria. A collaborative mathematical modeling project (with Cornelia Ulrich of the Fred Hutchinson Cancer Research Institute and Fred Nijhout of the Duke Department of Biology) has the goal of understanding the quantitative and qualitative emergent properties of the whole biochemical network.  Published and current work will be described as well as the difficulties involved. Several public health issues will also be discussed.

Lecture III:  Thursday, 10 November, 2005  at 15:30

Room 001, Physics Building


Propagation of Fluctuations Through Bio-chemical Networks


Analysis of the propagation of stochastic fluctuations through bio-chemical networks poses new, interesting mathematical problems and has proven to be a useful tool for understanding biological function. For each signal, either external or internal, that  causes a particular cell to dramatically change its operation, there are two natural questions. First, how does the gene-biochemical network respond to accomplish the change? Second, how does the network enable the cell to maintain homeostasis in all its other operations despite the change? One would like to understand the structural and kinetic principles that allow the network to accomplish both tasks simultaneously. Two distinct approaches will be described. First, we study how fluctuations propagate through relatively simple systems. We are interested in discovering how different network geometries magnify or suppress fluctuations since  this may give clues to why biochemical networks look the way they do. Secondly, we apply fluctuations to in silico representations of specific biological networks. By observing how fluctuations propagate we can identify reactions or subsystems that are buffered against such fluctuations, i.e. are homeostatic. Then, through in silico experimentation (e.g. removing particular reactions), we can take the system apart piece by piece to discover the regulatory mechanisms that give rise to the homeostasis