Nissl stain

More recently, Rademacher et al. applied quantitative criteria in Nissl stained sections to identify the borders of primary auditory cortex in 27 postmortem brains (14 females), and also concluded that there is not a consistent hemispheric asymmetry (Rademacher et al., 2001a, b). Their delineation of primary cortex included an expanded area that extended across Heschl s sulcus. They did not measure the volume of the smaller area that corresponds to the classical primary auditory cortex restricted to HG (their Tel.O) (Morosan et al., 2001). 

Fig. 5. The plate illustrates the ventral midbrain tegmentum as illustrated in the atlas of the rat brain of Swanson (1992), at levels approximately equivalent to those shown in Fig. 4. B and D are images of Nissl-stained sections. Abbreviations CLI, central linear nucleus of the raphe cpd, cerebral peduncle DGlb, dentate gyrus, lateral blade EW, Edinger-Westphal nucleus fr, fasciculus retroflexus hf, hippocampal fixure IF, interfascicular...

Architecture of the MOB (A, B) and primary olfactory cortex (POC, C). A and B Coronal section (Nissl stain) of the rat MOB at low (A) and high (B) magnifications. C Coronal section through the rat brain showing several structures of the POC. Abbreviations ac, anterior commissure Acb, nucleus accumbens AONvp, anterior olfactory nucleus, ventroposterior division DP, dorsal peduncular cortex IL, infralimbic cortex Pir, piriform cortex SEL, subependymal layer Scale bar in A and C = 1 mm. Modified from Handbook of Chem. Neuroanat. Integrated Sys. CNS, Vol. 12, Part III, Chapter III, The Olfactory System, M. Shipley etal., pp. 469-573,1996, with permission from Elsevier... 

The EPL lies beneath or deep to the glomeruli, and it primarily consists of dense neuropil formed by the dendrites of mitral cells and GCs that ascend from the MCL and GCL, respectively. Relative to other MOB layers, the EPL has a low cell density. In Nissl-stained sections, however, it can nevertheless be seen to contain significant numbers of neurons ( Figure 6-3). These include several subtypes of tufted cells and intrinsic interneurons, which are described later. Because tufted cells are in many aspects similar to mitral cells, and as mitral and tufted cell dendrites cannot be distinguished ultrastructurally, the term mitral/tufted cell is often used when generalizing to these two cell populations. The dominant feature of the EPL is nevertheless the extensive dendrodendritic synapses between mitral/tufted cells and GCs. 

Fig. 12. The distribution of GluR-A flip and flop mRNAs in the adult rat neocortex (emulsion autoradiographs). (A), Nissl stain (B), GluR-A flip ((7), GluR-A flop. Roman numerals indicate cortical layers. Arrows indicate examples of labelled cells. A strong band of flip-expressing cells is present in layer II of panel B (Wisden and Seeburg, unpublished).

Minicolumns Based on Vertical Arrays of Neuronal Cell Bodies Seen in Nissl Stained Sections... 

Fig. 8 Nissl stained section of primary auditory cortex, area 41, from a human cerebral hemisphere. In this cortical area there are obvious vertical strings of neurons arrows) separated by pale spaces that are largely occupied by the apical dendrites of pyramidal cells. Scale bar = 100 p,m...

One reason why more studies like that of Gabbott (2003) have not been carried out is that most studies of the composition and dimensions of dendritic clusters and pyramidal cell modules have been carried out in mice, rats, cats, and rabbits, with a few studies in monkeys and only one in humans (see Table 1). In contrast all of the studies of the dimensions of minicolumns based on spacing of vertical strings of neurons in Nissl stained sections have been carried out in monkeys, ape, and human cortex (see Table 2). 

The real point of making measurements of minicolumns from digitized images of Nissl stained material is to determine if there are alterations in the dimensions of the minicolumns between species, in disease states, and in the brains of humans with behavioral disorders. 

There have been a number of smdies on the features and dimensions of minicolumns seen in digitized images of vertical Nissl stained sections taken from the brains of patients with a variety of disorders. They will not all be considered here. Consideration will only be given to the differences that have been reported in Alzheimer s disease, in normal aging and in autism, which is the focus of this book. 

Buldyrev et al. (2000) used a quantitative method derived from condensed matter physics to examine the disposition of neurons in Nissl stained sections from the inferior bank of superior temporal sulcus in normal human brains, in brains from patients with Alzheimer s disease, and in patients with dementia resulting from Lewy body disease. In control brains they find evidence for the presence of minicolumnar ensembles with a periodicity of about 80 xm, but in brains from Alzheimer s patients in whom there is a loss of neurons, they report an almost complete loss of the minicolumnar organization. Further, the relative degree of loss of the minicolumnar organization appears to be directly proportional to the number of neurofibrillary tangles present, but not to the amount of f)-amyloid. In brains... 

Casanova et al. (2002) have compared the brains from autistic individuals with normal brains and found that in Nissl stained vertical sections taken from Brodmann s areas 9, 21, and 22, the minicolumns in the normal and autistic brains have a somewhat different structure. In the autistic brains, the minicolumns are smaller in width, and the neurons within the vertical strings are less tightly packed, leading the authors to conclude that per unit volume of cerebral cortex, the minicolumns are more numerous in the cortices of autistic individuals. Since studies by earlier authors have shown that there is no abnormality in cell density in the cortices of autistic individuals compared to controls (Coleman et al., 1985 Bailey et al., 1993), Casanova et al. (2002) suggest that autism is the consequence of a defect in migration of cells into the cortex during development. 

Fig. 3. A. Nissl-stained section of the cerebellar cortex of the cat. G = Golgi cell Gr = granule cells P = Purkinje cell, asterisks protoplasmatic islands of Held, Bar = 20 fira. B. diagram of the cerebellar cortex of Purkinje (1837).

---