Dr. Richard Bertram

Research Interest

• Mathematical and Computational Neuroscience
• Mathematical Physiology
• Dynamical Systems

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 at the National Institutes of Health and Les Satin at the University of Michigan Medical School.

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 located near 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, Joel Tabak, Arturo Gonzalez-Iglesias, and Maurizio Tomaiuolo (all at FSU) in the development and testing of mathematical models 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.

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).

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 is done in collaboration with done in collaboration with Artie Sherman and Victor Matveev.

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 in zebra finches. I work with Johnson and Wu to quantify the experimental data and, in the future, to develop models of the neural network controlling song production.

Selected Recent Publications