Electrophysiology

Example of neuronal responses to single (above) and multiple (below) electrical stimuliMathematical analysis frequently assists the understanding of how microscopic properties combine to produce the macroscopic properties; this is especially well illustrated in analysis of electrical responses in excitable cells. Intra- and extra-cellular recordings of neuronal responses can reveal the effects of ion channels that contribute to the generation and spread of complex neuronal signals.

In this module, students will record synaptic- and action-potentials arising spontaneously, or by electrical or pharmacological stimulation. Students will direct single or trains of electrical stimuli to the cell body (intracellularly, resulting action potentials right) or nerve processes (extracellularly, anatomy below) and observe responses. Selected cells will be pharmacologically manipulated by the application of Tetraethylammonium (TEA). Anatomy of the Ganglia and nerve processes. Note cell bodies are faintly visiable in center of ganglia These procedures will provide the opportunity to study changes in the passive (membrane), transitional (spike-production) and active (firing rate) properies of recorded cells.

Morphology

The morphology of recorded cells will be visualized by Lucifer Yellow staining and confocal microscopy imaging. A cluster of cell bodies stained by Lucifer Yellow and visualized on a confocal microscope

Images obtained by backfilling peripheral nerves provide an understanding of the overall arragement of clusters of cell bodies, their dendritic arborization and processes (right). Images obtained by intracellularly filling individual cell bodies show their processes in greater detail (left) and allows for more precise measurment of process diameters and segment lengths.Staining a single cell (cell body shown upper left) reveils the details of its dendritic arborization (below)

Using both elecrophysiological and morphological data they acquire, students will compare their results to existing mathematical models describing the mechanisms underlying potential generation and spread.