Biomedical Engineering Application Brief

Sensory Reception

The Solution

Looft and Baltensperger chose DADiSP, the graphic display data processing software package from DSP Development Corporation, to become an integral part of their complex lab set-up for recording, measuring, and analyzing the response of cat skin receptors. Dr. Looft acquired version 1.0 as his first copy of DADiSP, and has been using it ever since for analysis of action potential data.

Recording Action Potentials

For the IEEE paper, cats were anesthetized and prepared for nerve examination. Their relevant nerve fibers were wrapped over a silver hook electrode. Action potentials were monitored on a speaker and recorded on a tape recorder for off-line analysis. The researchers ascertained a mechanoreceptor's gross response characteristics by gently stroking a cat's leg with a glass rod and listening.

Sensory Signal Processing

A point probe was next used to get more specific information. This probe consisted of a moving coil motor with a cylindrical probe, a position sensor, and an electronic controller. This point probe was touched systematically to different places on the receptor sites, and the responses were low-pass filtered. The data then went to DADiSP for several kinds of calculation, including auto- and cross-spectral estimation, transfer function calculation, and coherence function calculation.

Easy to Test New Ideas

Dr. Looft says that one of the things he appreciates most about DADiSP is the ease with which he can use it to test out new ideas. He says, "If you get an inspiration and you want to try something, you don't have to write a program; you can just sit down and crunch through the data using DADiSP....You can use DADiSP to get ideas for ways to process data." Because the signals he works with require so much effort to record, being able to get the most out of them is vital for streamlining his time and minimizing costs. He also uses DADiSP's display capabilities and user-friendliness to help him teach undergraduate and graduate students. "I can demonstrate things to them and say, "I didn't have to write a program to show you this. Here's what happened in the experiment we just did, and here's what the data look like." He finds DADiSP a useful all-around tool, and over the years keeps coming up with more ways to use it.

DADiSP for Numeric Modeling

Looft and Baltensperger's cat study indicates that the type of skin receptor they examined seems to code differences in light touch with greater distinction than differences in heavy pressure. Dr. Looft is now using the data to develop detailed analytical and numerical models of the system structure of the tactile receptors. He anticipates that he will complete much of the preliminary data analysis and data processing algorithm development with his upgraded DADiSP.