Scott

SCOTT N. CURRIE, PH.D.

Associate Professor of Neuroscience
Go to Currie Neuroscience Faculty profile

EDUCATION:
BA, Biology, University of California, San Diego; La Jolla, CA.
M.S., Biology, Northeastern University Marine Science Center, Nahant, MA.
Ph.D., Animal Physiology, University of California, Davis; Davis, CA.
Postdoctoral training, Washington University; St. Louis, MO.

RESEARCH SUMMARY:
Coordinated rhythmic movements (e.g., breathing, walking, swimming, scratching) are characterized by precise temporal sequences of muscle activation referred to as motor patterns or motor programs. Motor pattern sequences are produced by rhythmically active networks of nerve cells called central pattern generators (CPGs) in the brain and spinal cord. Most of my work, funded by an NSF grant, examines cellular- and circuit-level mechanisms used by spinal cord CPG networks to generate rhythmic swimming and scratching movements in the turtle hindlimb. Both whole-animal (in situ) and isolated spinal cord (in vitro) preparations are used in these studies. The understanding of CPG mechanisms in biological neural networks is relevant to the understanding of human movement disorders and the design of biologically based ("biomimetic") control systems in robotics.

We recorded the first fictive swimming motor patterns in turtles that were immobilized by a neuromuscular blocking agent (Juranek and Currie, 2000). "Fictive" motor patterns are recorded directly from muscle nerves, without actual movement. We elicit fictive swim activity by electrically stimulating descending fiber tracts in a specific region of the spinal cord. Brief stimulation of a scratch reflex during ongoing fictive swimming can interrupt and permanently reset the rhythm of the swim. This shows that there are strong central interactions between swim and scratch neural networks, and suggests that they may share key timing elements. I have begun investigating pre-motor command systems in the turtle brainstem that activate locomotor CPGs in the spinal cord.

Click image below for
SCRIPTA ELEGANS

A number of years ago, I collaborated with Dr. Joseph Ayers and several engineers on a project to design and build biomimetic underwater robots for use in mine detection. The ultimate goal of this work, funded by DARPA-CBS, is to use finite-state-machine controllers, organized into command, coordinating and CPG systems, to control (1) an 8-legged ambulatory robot based on the lobster, and (2) an undulatory swimming robot based on the lamprey (an eel-like lower vertebrate). My part in this project was to assist in the "reverse engineering" of lamprey swimming, turning, and orientation behaviors from the animal to the robot. Shape-memory-alloy (nitinol, or Flexinol™) wires, which shorten by about 5% in response to a train of current pulses, are used as "artificial muscle" to produce robotic movement. This work is described in the new book "Neurotechnology for Biomimetic Robots", published by MIT Press.

Click on image to see movie (https://youtu.be/zNCqh1ew6K4).
Soft rubber lamprey model, fabricated for the Biomimetic Underwater Robot Program.

The model swam via passively conducted undulatory waves while suspended beneath a frictionless air track.

Undulatory oscillations were generated by a DC motor via a thin rod, inserted into the model just behind the "head"
and driven by a sine wave from a function generator. By manually adjusting the sine wave's DC offset,

the model could be made to turn right or left.

Publications: See faculty webpage

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