Computational Neuroscience

Spring 2005

Bard Ermentrout

Jon Rubin

Coordinates:

Lectures: Tues/Thur 9:00 AM - 10:30 AM Thackeray 527


Instructors:

Bard Ermentrout

Jon Rubin

Text

Theoretical Neuroscience

by Larry Abbott and Peter Dayan.

Additional Useful Texts:


Grading

Grades will be based on homework (60%) and final projects (40%). The final project can be done individually or in small teams (preferred). This must be a COMPUTATIONAL project in which you actually do some computation. You should start thinking about projects early on and get an OK from me before embarking on them. You will have to make a written report and perhaps (time permitting) give an oral report.

Some useful links


Syllabus


What is a neuron?

Neurons are specialized cells designed to rapidly communicate signals over long distances in the body. Like all cells, neurons consist of a cell membrane which separates the outside world from the cell itself.

A schematic picture of a neuron

Cells can have very complex shapes but over all have the following parts The soma,axons and often, the dendrites contain numerous ion channels which act to amplify or supress incoming signals and help send these out to other cells.

The signals in neuron are electrical and are measured as the difference in potential between the inside and the outside of the cell. This difference is called the membrane potential . Under normal conditions it is about -70 mV .

Signals from the outside and from other neurons tend to change the membrane potential: those that make it more negative are said the hyperpolarize while those that make it more positive are said to depolarize the cell.

Once a cell is sufficiently depolarized and the potential crosses a threshold , ion flows act in a positive feedback to cause the neuron to fire a action potential . Action potentials are generally 100 mV above rest. Action potentials cause short term and long term changes in the cell's ability to fire. In particular, once a cell has fired there is a period of time, the refractory period before which the cell cannot easily fire again. This can last up to several tens of milliseconds.

Once a cell has fired, the action potential travels down the cell's axon where it terminates on a specialized structure called a synapse . Synapses release chemicals called transmitters which depolarize or hyperpolarize the postsynaptic cell's dendrite or soma.

A synapse

Recording cells

An experimentalist can record electrical activity from one or more ways. The two most common methods are