Total numbers of neurons in the layers of the human entorhinal cortex. Hippocampus 1998;8:69–82
✍ Scribed by Mark J. West; Lutz Slomianka
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 31 KB
- Volume
- 8
- Category
- Article
- ISSN
- 1050-9631
No coin nor oath required. For personal study only.
✦ Synopsis
A correction factor related to the difference between the distance that the plane of focus of dry lens moves through a section and the distance that the section moves relative to the surface of the section (Galbraith, 1955) was omitted from the calculations used in our recent paper, in which we estimated the total numbers of neurons in the various layers of the entorhinal cortex of humans. This omission resulted in a systematic distortion in the measurement of the height h of the optical disectors, with the consequence that the true h of the disectors was 16.6 m rather than the 10 m that was used in the calculations. Because the thickness of the sections was determined with an oil objective, which produces minimal distortions of this type, a systematic error existed in the determination of the ''thickness sampling fraction,'' or tsf, used in the formula to estimate the total number of neurons according to the optical fractionator method (p. 71). Accordingly, the tsf should have been 1.66 times larger than that used, with the consequence that the estimates should have been 1.66 times smaller than those reported. The correct estimates are presented here in Table 1. It should be noted that the relative variances of the individual (CE) and group (CV) estimates are not changed, and that the correct values of the estimates are now more compatible with those reported by Gomez-Isla et al. (1996) and the recent figures published by Krimer et al. (1997). The major conclusion that ''the perforant path system is truly divergent and that different components have different degrees of divergence'' is not altered in that the lower estimates resulting from the correction increase the estimate of divergence both between layer II entorhinal cells and dentate granule cells, and between later III entorhinal cells and CA1, by a factor of 1.66.