Restricted (Penn State Only)
Billard, Myles William
Graduate Program:
Engineering Science and Mechanics
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 14, 2017
Committee Members:
  • Bruce Gluckman, Thesis Advisor
  • Kevin Douglas Alloway, Committee Member
  • Mark William Horn, Committee Member
  • Neurophysiology
  • Microdrive
  • Sleep
  • Wake
  • Circuits
  • Systems
  • Electrophysiology
  • Neural Recordings
  • Brainstem
Current neurophysiology tools for chronic recording experiments in small freely-behaving animals are not capable of driving electrodes to multi-site, multi-regional targets at different angles and with greater than two implant axes. Here, we present a novel microdrive system designed to address these limitations for studying distributed behavioral neural circuits. Our design decouples the surgical implantation of a guide cannula with placement of a flexible tube structure to create multiple, independent drive axes with set drive trajectories and electrode depths. The system leverages tight tube-cannula tolerances and geometric constraints on the flexible drive axis to ensure concentric alignment of electrode bundles within guide cannulas as they move through tissue. Acute experiments included targeting of three separated brain targets at radically different trajectory angles to demonstrate the accuracy of the drive axis placement method. Chronic recording experiments involved targeting and recording from three non co-localized and non-collinear cell groups in brainstem of rats. Data from these experiments included identification of multiple neuron discharge waveforms over multiple spatial points as electrodes were driven through tissue. Additionally, sleep-wake behavior correlates were identified using external sensing modalities supported by the microdrive design. This is the first reported instance of a microdrive capable of monitoring neural activity from simultaneous multiple targets along independently-angled trajectories from a single body structure.