The Journal of Neuroscience, November 15, 2000, 20(22):8485-8492
Distributed and Partially Separate Pools of Neurons Are
Correlated with Two Different Components of the Gill-Withdrawal Reflex
in Aplysia
Michal
Zochowski1, 2, 5,
Lawrence B.
Cohen1, 2,
Galit
Fuhrmann2, 3, and
David
Kleinfeld2, 4
1 Department of Molecular and Cellular Physiology, Yale
University School of Medicine, New Haven, Connecticut 06520, 2 Marine Biological Laboratory, Woods Hole, Massachusetts
02543, 3 Center for Neural Computation, The Hebrew
University, Jerusalem, Israel 91904, 4 Department of
Physics, University of California at San Diego, La Jolla, California
92093-0319, and 5 Center for Theoretical Physics, Polish
Academy of Science, 02-668 Warsaw, Poland
We compared the spike activity of individual neurons in the
Aplysia abdominal ganglion with the movement of the gill
during the gill-withdrawal reflex. We discriminated four populations that collectively encompass approximately half of the active neurons in
the ganglion: (1) second-order sensory neurons that respond to the
onset and offset of stimulation of the gill and are active before the
movement starts; (2) neurons whose activity is correlated with the
position of the gill and typically have a tonic output during gill
withdrawal; (3) neurons whose activity is correlated with the velocity
of the movement and typically fire in a phasic manner; and (4) neurons
whose activity is correlated with both position and velocity. A
reliable prediction of the position of the gill is achieved only with
the combined output of 15-20 neurons, whereas a reliable prediction of
the velocity depends on the combined output of 40 or more cells.
Key words:
distributed activity; motor planning; neural coding; neural networks; optical recordings; optimal filtering
Copyright © 2000 Society for Neuroscience 0270-6474/00/20228485-08$05.00/0