Distributed and partially separate pools of neurons are correlated with two different components of the gill-withdrawal reflex in Aplysia.
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.
Zochowski
M
M
Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA. mrz@fred.med.yale.edu
Cohen
L B
LB
Fuhrmann
G
G
Kleinfeld
D
D
D000200:Action Potentials / Q000502:physiology; D000465:Algorithms; D000818:Animals; D001048:Aplysia / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D002452:Cell Count; D004558:Electric Stimulation; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000502:physiology; D005880:Gills / Q000294:innervation* / Q000502:physiology; D066298:In Vitro Techniques; D008959:Models, Neurological; D009475:Neurons, Afferent / Q000145:classification / Q000166:cytology / Q000502:physiology*; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D012018:Reflex / Q000502:physiology*