Portable conduction velocity experiments using earthworms for the college and high school neuroscience teaching laboratory.

The earthworm is ideal for studying action potential conduction velocity in a classroom setting, as its simple linear anatomy allows easy axon length measurements and the worm's sparse coding allows single action potentials to be easily identified. The earthworm has two giant fiber systems (lateral and medial) with different conduction velocities that can be easily measured by manipulating electrode placement and the tactile stimulus. Here, we present a portable and robust experimental setup that allows students to perform conduction velocity measurements within a 30-min to 1-h laboratory session. Our improvement over this well-known preparation is the combination of behaviorally relevant tactile stimuli (avoiding electrical stimulation) with the invention of minimal, low-cost, and portable equipment. We tested these experiments during workshops in both a high school and college classroom environment and found positive learning outcomes when we compared pre- and posttests taken by the students.

[1]  Joseph Krajcik,et al.  Standardized Test Outcomes for Students Engaged in Inquiry-Based Science Curricula in the Context of Urban Reform. , 2008 .

[2]  J. Nicol.  The Giant Axons of Annelids , 1948, The Quarterly Review of Biology.

[3]  A. Hodgkin,et al.  Action Potentials Recorded from Inside a Nerve Fibre , 1939, Nature.

[4]  G. Gage,et al.  The SpikerBox: A Low Cost, Open-Source BioAmplifier for Increasing Public Participation in Neuroscience Inquiry , 2012, PloS one.

[5]  D. Hartline,et al.  Rapid Conduction and the Evolution of Giant Axons and Myelinated Fibers , 2007, Current Biology.

[6]  Bruce R. Johnson,et al.  Tools for physiology labs: an inexpensive high-performance amplifier and electrode for extracellular recording , 2001, Journal of Neuroscience Methods.

[7]  K. Kusano.  Electrical activity and structural correlates of giant nerve fibers in Kuruma shrimp (Penaeus japonicus) , 1966 .

[8]  H. S. Gasser,et al.  The classification of nerve fibers. , 1941 .

[9]  C. Drewes,et al.  Giant nerve fibre activity in intact, freely moving earthworms. , 1978, The Journal of experimental biology.

[10]  Abigail Jurist Levy,et al.  Inquiry-based science instruction—what is it and does it matter? Results from a research synthesis years 1984 to 2002 , 2010 .

[11]  H. Barlow,et al.  Single-Fibre Response from an Intact Animal , 1943, Nature.

[12]  Gregory J Gage,et al.  Using crickets to introduce neurophysiology to early undergraduate students. , 2013, Journal of undergraduate neuroscience education : JUNE : a publication of FUN, Faculty for Undergraduate Neuroscience.

[13]  Bruce R. Johnson,et al.  Optogenetics in the teaching laboratory: using channelrhodopsin-2 to study the neural basis of behavior and synaptic physiology in Drosophila. , 2011, Advances in physiology education.

[14]  Michael J. Prince,et al.  Inductive Teaching and Learning Methods: Definitions, Comparisons, and Research Bases , 2006 .

[15]  J. Dubinsky.  Neuroscience Education for Prekindergarten–12 Teachers , 2010, The Journal of Neuroscience.

[16]  F. Bezanilla,et al.  Seasonal variation in conduction velocity of action potentials in squid giant axons. , 2000, The Biological bulletin.

[17]  J. Günther.  Overlapping sensory fields of the giant fiber systems in the earthworm , 1973, Naturwissenschaften.

[18]  Nikolay Kladt,et al.  Teaching Basic Neurophysiology Using Intact Earthworms , 2010, Journal of undergraduate neuroscience education : JUNE : a publication of FUN, Faculty for Undergraduate Neuroscience.

[19]  Helen R. Quinn.  A Framework for K-12 Science Education , 2012 .

[20]  Howard Brown Stough.  Giant nerve fibers of the earthworm , 1926 .

[21]  H. S. Gasser,et al.  POTENTIALS PRODUCED IN THE SPINAL CORD BY STIMULATION OF DORSAL ROOTS , 1933 .

[22]  Polarization of the giant nerve fibers of the earthworm , 1930 .

[23]  W A H RUSHTON,et al.  Reflex conduction in the giant fibres of the earthworm , 1946, Proceedings of the Royal Society of London. Series B - Biological Sciences.

[24]  Theodore H. Bullock,et al.  FUNCTIONAL ORGANIZATION OF THE GIANT FIBER SYSTEM OF LUMBRICUS , 1945 .

[25]  The Giant Fibre Reflex of the Earthworm, Lumbricus Terrestris L , 1962 .

[26]  J. Csicsvari,et al.  Intracellular features predicted by extracellular recordings in the hippocampus in vivo. , 2000, Journal of neurophysiology.