Processing a Neurological Multiunit-Activity Signal
Multiunit activity (MUA) is the superimposed neuronal signal collected from a region of neurons. The code for this Demonstration is based on the MUA preprocessing methods adopted in  and . We can visualize what kind of changes one could observe by changing the sampling frequency and filtering frequency for various standard functions (or signals), as if they had been processed from an actual raw MUA signal.
The signal was filtered from 300 Hz to 4000 Hz using a fourth-order Butterworth filter and was further clipped at about two times the standard deviation. The output was further filtered using a fourth-order lowpass Butterworth filter at a frequency determined by the sampling frequency. In order to avoid a phase shift, filtered reverse data was added to filtered output.
The content of this Demonstration is a part of my master's thesis research (used for MUA signal processing) at Dr. Michel A. Lemay's lab.
 N. AuYong, K. Ollivier-Lanvin, and M. A. Lemay, "Population Spatiotemporal Dynamics of Spinal Intermediate Zone Interneurons during Air-Stepping in Adult Spinal Cats," Journal of Neurophysiology, 106(4), 2011 pp. 1943–1953. doi:10.1152/jn.00258.2011.
 C. M. McMahon, "Lumbar Spinal Interneuron Activity as It Relates to Rhythmic Motor Output in the Adult, Spinal, Air-Stepping Cat," Ph.D. dissertation, Drexel University, Philadelpha, ProQuest, UMI Dissertations Publishing, 2014. gradworks.umi.com/36/29/3629481.html.