Somadendritic backpropagation of action potentials in cortical pyramidal cells of the awake rat. Gy”rgy Buzs ki and Adam Kandel. Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102,.
APStracts 4:322N, 1997.
ABSTRACT
The invasion of fast (Na+) spikes from the soma into dendrites was studied in pyramidal cells of the sensorimotor cortex by simultaneous extracellular recordings of the somatic and dendritic action potentials in freely behaving rats. Field potentials and unit activity were monitored with multiple-site silicon probes along trajectories perpendicular to the cortical layers at spatial intervals of 100 ĉm. Dendritic action potentials of individual layer V pyramidal neurons could be recorded up to 400 ĉm from the cell body. Action potentials were initiated at the somatic recording site and traveled back to the apical dendrite at a velocity of 0.67 m/sec. Current source density analysis of the action potential revealed time shifted dipoles, supporting the view of active spike propagation in dendrites. The presented method is suitable for exploring the conditions affecting the somadendritic propagation action of potentials in the behaving animal. 

Received 29 September 1997; accepted in final form 14 November 1997.
APS Manuscript Number J791-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 12 December 1997