Table 1.

Axonal action potential properties from recent studies of cell types in three major brain regions.

Brain Area	Cell Type	Tissue Species	Animal Age	Temp (°C)	Axon Myelination Status	Conduction Velocity (m/s)	Est. AP Initation Site (μm from soma)	Recording Configuation	Reference
neocortex	layer 5 pyr	Rat	P26-30	35	?	antidromic 0.3 –0.4	≥ 30	dual whole-cell soma and axon initial segment	Stuart et al., 1997
	layer 5 pyr	Rat	P14-24	23	?	?	≥ 30	axon initial segment patches, whole-cell soma	Colbert and Pan, 2002
	layer 5 pyr	Rat	P21-35	34	starting at ~40 um	orthodromic ~0.4	~35	whole-cell soma, voltage sensitive dyes	Palmer Stuart, 2006
	layer 5 pyr	Rat	P12-60	34	starting at ~50 um	orthrodromic 2.9	~38	dual whole-cell soma and axon bleb	Kole et al., 2007
	layer 5 pyr	ferret	P49-56	36.5	starting at ~200 um	orthrodromic 0.83 antidromic 0.77	40–55	dual whole-cell soma and axon bleb	Shu et al., 2007
cerebellum	Purkinje	Rat	P13-31	22	Yes	?	≥ 7	dual whole-cell soma and axon initial segment	Stuart and Hausser, 1994
	Purkinje	mouse	P15-29	33	yes	orthrodromic 1	~30	dual whole-cell soma and axon loose-seal	Khaliq and Raman, 2006
	Purkinje	Rat	P18-26	34	starting at ~20 um	orthrodromic 0.77 antidromic 0.56	75+−11	dual soma attached recording and axon loose-seal	Clark et al., 2005
hippocampus	CA3 pyr	Rat	P 18-22	25	not within 1 mm	orthrodromic 0.3	35–40	dual whole-cell soma and axon loose-seal	Meeks and Mennerick, 2007
	CA3 pyr	Rat	P21-84	23	unmyelinated	estimated ~0.23	NA	Antidromic stimulation, CA3 unit	Soleng et al., 2003a
	dentate granule	Rat	P17-23	25	not within 1 mm	orthrodromic 0.25	~40	dual whole-cell soma and axon loose-seal	Kress et al., 2007
	dentate granule	Rat	P30-50	33	?	antidromic 0.67	?	antidromic population spike	Langdon et al. 1993
	subicular pyr	Rat	P14-56	24	yes	?	30–60	dual whole-cell soma and axon initial segment	Colbert and Johnston 1996

Est estimate, AP action potential, Temp temperature, Pyr Pyramidal.