Conduction velocity costs energy

Hodgkin and Adrian’s 1975 hypothesis that the squid axon is optimized for maximum conduction velocity is flawed by (i) the inaccurate value of its prediction for channel density, and (ii) the prohibitive energetic expense entailed by their prediction. Here we investigate the metabolic cost of conduction velocity. By manipulating ion channel density or by manipulating the Nernst battery voltages, we demonstrate that action potential velocity has a significant metabolic cost. Thus, in addition to the cost of information transmission (Neural Comput. 8(1996) 531 [9]), there is a cost associated with the timely arrival of such transmitted information. r 2004 Elsevier B.V. All rights reserved.