Motor neuron numbers from the spinal cords of the ageing cohort.

Mean motor neuron counts from spinal cord sections from the ageing cohort. WT indicates wild-type animals, HET indicates heterozygote animals N  =  number of animals in the group, Mean  =  average of group, Min  =  minimum reading of group, max  =  maximum reading of group, S.D  =  standard deviation. No differences were significant.