CELL SIZES AND FREQUENCIES IN HUMAN NUCLEUS INTERCALATUS

A considerable area of the floor of the fourth ventricle, extending from the facial colliculus down to the vagal triangle, is underlaid by the nerve cells of the nucleus intercalatus. Only a minor portion of this nuclear complex is actually “intercalated” this portion comprising about 2,500 cells or 6% of the total. The great majority of cells making up this nucleus, 80% or 32,000 are found in front of the oral pole of the hypoglossal nucleus. The remaining 14% of cells or about 6,000 form a third distinct group located opposite the medial vestibular nucleus. The mean cell sizes in the three parts of the nucleus are also different, they are 90 μ2, 135 μ2 and 190 μ2 respectively. These differences of cell sizes and of location were the basis for the division of this nucleus into three parts by some authors. In the three cases studied, this division was, however, not so complete as to permit a separate cell count for each part to be kept. The mean of the cell frequencies in the three cases is 36349 ± 4114 cells. Copyright © 1968 Wiley‐Liss, Inc.