Table 4.

Comparison of α-spinal motor neurons and oculomotor neurons.

	Spinal α-MN	Oculomotor neuron
Target muscle fiber	Single fiber type1	Multiple fiber types1
Soma size	Larger2,3	Smaller2,3
Dendrite branching	Larger2	Smaller2
Motor unit size (innervation ratio)	Larger4,5,6,7	Smaller4,5,6,7
Resting potential	Smaller8,9,10	Higher8,9,10
Discharge frequency	100 Hz8,9,10	100–600 Hz8,9,10
Affected in ALS	Yes11,12,13,14	No11,12,13,14
Affected in aging	Yes15,16	No15,16

¹(Zhou et al., 2011), ²(Durand, 1989), ³(Shoenfeld et al., 2014), ⁴(Burke et al., 1971), ⁵(Burke and Tsairis, 1973), ⁶(Enoka, 1995), ⁷(Guéritaud et al., 1985), ⁸(Robinson, 1970), ⁹(Fuchs et al., 1988), ¹⁰(Torres-Torrelo et al., 2012), ¹¹(Nimchinsky et al., 2000), ¹²(Hedlund et al., 2010), ¹³(Valdez et al., 2012), ¹⁴(Comley et al., 2016), ¹⁵(Hashizume et al., 1988), ¹⁶(Swash and Fox, 1972).