Richard Bertram


Associate Professor, Department of Mathematics
Graduate Faculty Member, Institute of Molecular Biophysics
Graduate Faculty Member, Program in Neuroscience
Florida State University

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Current Research Interests

Activity of Pancreatic Beta-Cells
Pancreatic Beta-cells are the only cells in the body that secrete insulin, a hormone that is necessary for the uptake of glucose by other cells. Defects in Beta-cell functioning lead to diabetes, which can result in death if not treated. The release of insulin is controlled by many physiological variables, including the cell's electrical activity, calcium, and nucleotide concentrations. I work in the development and analysis of mathematical models of Beta-cell activity. This work is done in collaboration with Artie Sherman and Les Satin. Graduate students Joe Rhoads and Bernard Fendler also work on this project, as does undergraduate student Rudy Arceo.

Hypothalamic Control of Hormone Secretion
The hypothalamus is the region of the brain that regulates the level and timing of hormone release from endocrine glands. One such gland, the pituitary, is connected to the hypothalamus, and secretions from this gland regulate secretions from other glands. For this reason, the pituitary is sometimes called the "master gland". The hypothalamus sends both stimulatory and inhibitory input to the pituitary, resulting in neural regulation of secretion from gonadotrophs, somatotrophs, corticotrophs, melanotrophs, and lactotrophs. I collaborate with Marc Freeman , Marcel Egli, and Joel Tabak to use mathematical modeling to help understand the complex cellular and network interactions involved in the secretion of prolactin from pituitary lactotrophs. Prolactin has many roles in the body, including milk production in the mammary gland. Graduate student Natalia Toporikova also works on this project.

Bursting Oscillations in Excitable Cells
In nerve cells, information is transmitted through electrical impulses. Electrical impulses also cause muscles to contract and endocrine cells to secrete hormones. Quite often, impulses are generated as high-frequency bursts, followed by periods of quiescence. This is particularly true in endocrine cells such as pancreatic Beta-cells. I am interested both in the dynamics of bursting (a mathematical topic) and in the mechanisms by which different cells generate periodic bursts of impulses (a biological topic). Current collaborators on this project are Joel Tabak and graduate student Natalia Toporikova.

Synaptic Transmitter Release and Short-Term Plasticity
Information is processed and transmitted in nerve cells by electrical impulses. These impulses are passed from one nerve cell to the next through a process called synaptic transmission. In the presynaptic cell, an impulse evokes the release of one or more chemical neurotransmitters. These transmitters diffuse to the postsynaptic cell and bind to transmitter receptors, resulting in a postsynaptic voltage change. I am working on the development of mathematical models that describe certain aspects of this process, incorporating much of the known biophysical data. The goal is to better understand transmitter release and the mechanisms behind the enhancement or depression of release, i.e., synaptic plasticity. My most recent work focuses on two mechanisms for plasticity: residual binding of calcium ions to vesicle binding sites, and on the effects of G-protein inhibition of calcium channels. The former work is done in collaboration with Artie Sherman and Victor Matveev. The latter research is done in collaboration with Gerald Zamponi . Undergraduate student Michelle Outlaw also works on this project.

Computational Structural Biology
I am currently developing computational methods that use data from solid-state NMR experiments to build models of the atomic structures of membrane-spanning proteins. This work is done in collaboration with Jack Quine, and Tim Cross. Former students involved in this work are Tom Asbury (now a postdoctoral fellow at the Medical University of South Carolina), Sai Achuthan (now a postdoctoral fellow at Luisiana State University Medical School), and Jun Hu (now a postdoctoral fellow at the National Institutes of Health).

Neural Network Controlling Bird Songs
This is my most recent project, done in collaboration with Frank Johnson, and Wei Wu. Song birds have a dedicated region of the brain to produce stereotyped songs. The Johnson lab is studying how this region of the brain controls vocalization and learns or relearns songs. I work with Jonson and Wu to quantify the experimental data and, in the future, to develop models of the neural network controlling song production.

Publications

Bursting in Nerve Cells
Pancreatic Beta-Cells
Synaptic Transmission
Structural Biology
Hypothalamic Control of Hormone Secretion
Birdsong Production
Other Topics

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Structural Biology
Pituitary
Synaptic Transmission
Pancreatic Islet
Neuron
Birdsong

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Full CV

Address

Dr. Richard Bertram
Department of Mathematics (or Institute of Molecular Biophysics)
Florida State University
Tallahassee, Fl 32306

tel.: (850)-644-7195
e-mail: bertram@math.fsu.edu