Fig. 5.

Paranodal length is conserved in the CNS. A) Mean paranodal length was not significantly different among the ages analyzed. B) A scatter plot of paranode length versus myelin thickness indicated that thicker myelin sheaths generally formed longer paranodal regions; however, the plot also indicates that the rate of paranodal lengthening is not maintained as myelin thickness increases. This difference in rate lengthening is demonstrated by graphing paranodes from myelin sheaths ≥ 0.25 um (C) separately from paranodes from myelin sheaths thinner than 0.25 μm (D). By calculating the best fit line for the two populations of paranodes, the rate of paranodal lengthening for thin sheaths was determined to be three times greater than the lengthening rate of thick sheaths.