The human lateral lemniscus and its nuclei. The human auditory pathways: a quantitative study.

Abstract Quantification of the human lateral lemniscus and its nuclei in 15 brains of patients without hearing impairment revealed these average values: Cross-sectional surface area of the bundle at the level of the nucleus of cranial nerve IV of 2.5 mm 2 , fiber density of 77,000/mm 2 ; 194,000 total fibers on each side; grouping of the nerve cells in three nuclei (olive remnant, ventral, and dorsal) the largest of which is the ventral; cell density in the olive remnant of 5009/mm 3 , in the ventral nucleus of 15,184/mm 3 , and 13,169 cells per mm 3 in the dorsal nucleus; total cell populations in all nuclei of 20,063 on the left and 26,137 on the right; glial-neuronal index of 9.2; cell dimensions of 23.6 × 15.4 microns in the olive remnant and 21.2 × 12.2 in the other nuclei; combined nuclear volume of 1.91 mm 3 . Loss of neurons was not apparent in the aged brains but a significant reduction in counts of axons and in lemniscal bulk appeared in two of the older brains of the series (77 and 91 years).