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A Control System for Positioning Recording Electrodes to Isolate Neurons in Extracellular Recordings


Branchaud, Edward Allan (2006) A Control System for Positioning Recording Electrodes to Isolate Neurons in Extracellular Recordings. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6HHC-5456.


This thesis presents an algorithm that autonomously positions recording electrodes inside cortical tissue so as to isolate and then maintain optimal extracellular signal recording quality without human intervention. The algorithm is used to improve the quality and efficiency of acute (daily insertion) recordings that are needed for basic research in neurophysiology. It also offers the potential to increase the longevity and quality of chronic (long-term implant) recordings by controlling an emerging class of chronic arrays in which the electrodes can be continually repositioned after implantation.

The challenges encountered in attempting to isolate neurons are studied. A solution is proposed in which a finite state machine oversees a number of signal processing steps, computes various metrics of the recording quality and issues commands to move the electrode close to neurons without causing them damage. A number of metrics of the quality of neuron isolation are compared.

The algorithm has been used to control a number of commercial microdrive systems, including a single-electrode FHC microdrive and multielectrode microdrives from Thomas Recording and NAN, as well as a novel miniature microdrive. The autonomous positioning software is used by several neuroscientists to perform basic neurophysiology research. Analysis of the system's performance in isolating neurons is included.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:electrode positioning; extracellular neural recording; neuron isolation
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Burdick, Joel Wakeman
Thesis Committee:
  • Burdick, Joel Wakeman (chair)
  • Dickinson, Michael H.
  • Andersen, Richard A.
  • Murray, Richard M.
Defense Date:24 May 2006
Non-Caltech Author Email:ebranchaud (AT)
Record Number:CaltechETD:etd-06042006-160620
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2445
Deposited By: Imported from ETD-db
Deposited On:05 Jun 2006
Last Modified:17 Apr 2020 22:31

Thesis Files

PDF (thesis_Branchaud_Edward_A.pdf) - Final Version
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