Scott N. Currie, Ph.D.

The goal of my research is to understand the physiological mechanisms underlying the control of behavior. My main focus is the spinal cord and brainstem control of limb movements in the turtle. The nervous system must generate precise temporal sequences of muscle contraction when an organism produces a coordinated movement. These programmed sequences of muscle activity are referred to as "motor patterns", and are produced by rhythmically active networks of nerve cells called "central pattern generators" (CPGs) in the central nervous system. Most of my research has examined cellular and network-level mechanisms that are utilized by spinal cord CPGs in the turtle to generate coordinated scratching and swimming movements of the hindlimbs. More recently, I have begun investigating (1) pre-motor command systems in the turtle brainstem that activate locomotor CPGs in the spinal cord, and (2) the limb kinematics and EMG motor patterns that underlie lateral (yaw) turns during turtle swimming. I am also interested in the interactions and coordination between turtle locomotor and respiratory systems. The investigation of sensory-motor control mechanisms in biological neural networks has direct impact on the design of biomimetic control systems in robotics and new approaches to the treatment of human spinal cord injury and paralysis.

Fictive swim motor pattern, elicited by electrical stimulation of the spinal cord DLF (dorso-lateral funiculus) at segment D3 and recorded from 3 hindlimb muscle nerves on the right side: a knee extensor (red), an hip flexor (violet) and an hip extensor (blue). The 30 Hz electrical stimulus pulses are shown in the bottom trace (black).

Recent Publications:

• Samara, R.F. and Currie, S.N.  (2008)  Electrically evoked locomotor activity in the turtle spinal cord hemi-enlargement preparation.  Neuroscience Letters 441: 105-109.

• Samara, R.F. and Currie, S.N.  (2008) Location of spinal cord pathways that control hindlimb movement amplitude and interlimb coordination during voluntary swimming in turtles.  Journal of Neurophysiology 99: 1953-1968.

• Samara, R.F. and Currie, S.N.  (2007)  Crossed commissural pathways in the spinal hindlimb enlargement are not necessary for right-left hindlimb alternation during turtle swimming. Journal of Neurophysiology 98: 2223-2231.

• Currie, S.N. (In preparation) Interaction between right and left hindlimb swim networks in the turtle spinal cord. To be submitted to the Journal of Neurophysiology.

• Currie, S.N. (In preparation) Different activity patterns in multifunctional turtle abdominal muscles during breathing and swimming. To be submitted to the Journal of Experimental Biology.

• Wilbur, C., Vorus, W., Cao, Y. and Currie, S. (2002) A lamprey-based undulatory vehicle. In: Neurotechnology for Biomimetic Robots (J. Ayers, J. Davis, A. Rudolph, eds.). MIT Press, Cambridge, MA.   [buy book]

• Juranek, J. and Currie, S.N. (2000) Electrically evoked fictive swimming in the low-spinal immobilized turtle. Journal of Neurophysiology 83: 146-155.

• Currie, S.N. (1999) Fictive hindlimb motor patterns evoked by AMPA and NMDA in turtle spinal cord-hindlimb nerve preparations. Journal of Physiology (Paris) 93: 199-211.

• Currie, S.N. and Gonsalves, G.G. (1999) Reciprocal interactions in the turtle hindlimb enlargement contribute to scratch rhythmogenesis. Journal of Neurophysiology 81: 2977-2987.

• Currie, S.N. and Gonsalves, G.G. (1998) Crossed reciprocal inhibition and scratch rhythmogenesis in the turtle spinal cord. Ann. NY Acad. Sci. 860: 458-460.

• Stein, P.S.G., McCullough, M.L. and Currie, S.N. (1998) Spinal motor patterns in the turtle. Ann. NY Acad. Sci. 860: 142-154.

• Ayers, J., Zavracky, P., McGruer, N., Massa, D.P., Vorus, W.S., Mukherjee, R. and Currie, S.N. (1998) A modular behavioral-based architecture for biomimetic autonomous underwater robots. Proceedings of the Autonomous Vehicles in Mine Countermeasures Symposium. Naval Postgraduate School. (Published on CD). [html version]

• Stein, P.S.G., McCullough, M.L., Currie, S.N. (1998) Reconstruction of flexor/extensor alternation during fictive rostral scratching by two-site stimulation in the spinal turtle with a transverse spinal hemisection. Journal of Neuroscience 18: 467-479.

• Currie, S.N. and Gonsalves, G.G. (1997) Right-left interactions between rostral scratch networks generate rhythmicity in the pre-enlargement spinal cord of the turtle. Journal of Neurophysiology 78: 3479-3483.

• Currie, S.N. and Lee, S. (1997) Glycinergic inhibition contributes to the generation rostral scratch motor patterns in the turtle spinal cord. Journal of Neuroscience 17: 3322-3333.

• Currie, S.N. and Lee, S. (1996) Sensory-evoked pocket scratch motor patterns in the in vitro turtle spinal cord: reduction of excitability by an N-methyl-D-aspartate antagonist. Journal of Neurophysiology 76: 81-92.

• Currie, S.N. and Lee, S. (1996) Glycinergic inhibition in the turtle spinal cord regulates the intensity and pattern of fictive flexion reflex motor output. Neuroscience Letters 205: 75-78.

• Stein, P.S.G., Victor, J.C., Field, E.C. and Currie, S.N. (1995) Bilateral control of hindlimb scratching in the spinal turtle: contralateral spinal circuitry contributes to the normal ipsilateral motor pattern of fictive rostral scratching. Journal of Neuroscience 15: 4343-4355.

CBNS/PSYC 127. Behavioral Control Systems: Comparative analysis of the principles of nervous system initiation and control of behavior, concentrating on motor systems. Topics include: (1) command neurons and motor hierarchies, (2) simple reflexes, (3) CPGs and motor pattern generation, (4) neuromodulation of multifunctional networks, (5) artificial neural networks, (6) development of behavior, (7) motor learning in the cerebellum, and (8) cortical control of voluntary movement. (Spring quarter)