Cell Tiss. Res. 153, 219--226 (1974) �9 by Springer-Verlag 1974

Regional Differences in the Distribution of Golgi Cells in the Cerebellar Cortex

of Man and Some Other Mammals*

W. Lange

Anatomisches Institut der Universitiit Kiel (Direktor: Professor Dr. med. Drs. h.e.W. Bargmann)

Received July 12, 1974

Summary. The number of Golgi cells per unit volume was determined in different regions of the eerebellar cortex of man and of ten other mammals. Despite the general belief in the uniform architecture of the cerebellar cortex, regional differences in the distribution of Golgi cells were found. In the inferior parts of the vermis, the number of Golgi cells per unit volume is twice that in the corresponding hemispheres. In addition, there are differences between the anterior and inferior parts of the vermis. These differences are a feature of the cytoarchitecture of the cerebellum in man and all the investigated mammals. The ratio of Purkinje cells to Golgi cells was also determined and found to differ in different species. In man, this ratio is 1:1.5, while in the monkey and cat it is almost 1:1.9 and in the rat 1:3.3. These differences in the ratio of Purkinje cells to Golgi cells are discussed from the point of view of cerebellar evolution.

Key words: Cerebellar cortex - - Man and other mammals - - Golgi cells - - Regional differences - - Light and electron microscopy.

The cerebellar cor tex of m a n and of o ther m a m m a l i a n species is genera l ly supposed to be essent ia l ly homogeneous and no t to d i sp lay regional differences in cy toarchi tec ture . Nevertheless , wi th var ious methods J a k o b (1928), Scot t (1963), Voogd (1967) and Korne l inssen (1968, 1969) could subs tan t i a t e a longi- tud ina l subdivis ion of the cerebel lar cortex. Fu r the rmore , J a k o b (1928), Csillik, Joo and K a s a (1963), Brodal and Drablos (1963), K a s a (1969), P a r m a (1969), P a r m a and Bald in i (1969), Lange (1972), and Spacek, Par izek and L iebe rman (1973) have given his tochemical and cy toa rch i t ec tu ra l evidence also for a specific t r ansversa l o rganiza t ion of the cerebel lar cortex.

As J a k o b (1928) a l r eady ment ions in his ve ry de ta i led descr ip t ion of the cy toa rch i t ec tu re of the cerebel lar cortex, the number of Golgi cells varies in different regions of the cerebellar cortex. Brodal and Drablos (1963) have conf i rmed these findings, showing t h a t in the inferior pa r t s of the vermis, and in the flocculus, Golgi cells are more f requent t h a n in the hemispheres ; however, t h e y d id no t p resen t a n y quan t i t a t i ve evidence per ta in ing to these differences. Spacek, Par izek and L iebe rman (1973) also have shown regional differences in the d i s t r ibu t ion of Golgi cells not in the g ranu la r layer , bu t in the molecular layer of r a b b i t and

Send offprint request8 to: Prof. Dr. W. Lange, Anatomisches Institut der UniversitKt, 23 Kiel, Neue Univ., Eingang F 1, Federal Republic of Germany.

* Supported by the Deutsche Forschungsgemeinschaft.

15"

220 W. Lange

hare. Recent ly , Mugnaini (1972) summar ized the l i t e ra ture on this subject , and po in ted out, t ha t we lack precise da t a as on regional differences in the d is t r ibu t ion of Golgi cells in the cerebellar cortex.

I t is the purpose of this inves t iga t ion to clarify with quan t i t a t i ve methods the differences in the regional d i s t r ibu t ion of Golgi cells in the anter ior , poster ior and f locculo-nodular lobe of the cerebellum. In addi t ion , the quest ion as whether regional differences in the d i s t r ibu t ion of Golgi cells are a specific s t ruc tura l fea ture of the human cerebellar cor tex or occur also in other mammals , will be considered.

Materials and Methods

Five human cerebella, 2 cerebella of rhesus monkey (Macaca rhesus), 2 cerebella of crab eating macaque (Macaca cynomolgus), 2 cerebella of cat (Felis domestica), 2 cerebella of ocelot (Felis pardalis), 2 cerebella of the G6ttinger mini pig (Sus scro/a,/, domestica), 2 cerebella of rabbit (Oryctolagus cuniculus), 2 cerebella of opossum (Didelphys virginiana), 2 cerebella of hedgehog (Erinaceus europaeus), 2 cerebella of rat (Rattus norvegicus) and 2 cerebella of mole (Talpa europaea) were used for this study.

The human cerebella were fixed in buffered formalin, embedded in paraffin, and 10 ~z sections were stained according the method of Einarson (Romeis, 1968). Golgi impregnations were made according to the modification of the Golgi procedure of Bubenaite (1929). The animals were perfused with glutaraldehyde (6%, 0.05 M Millonig-phosphate-buffer, pH 7.2). The cerebella were removed and pieces postfixed for one hour in a 1% OsO~ solution and embedded in Epon 812. Semithin sections were stained by the method of Ito and Winchester (1963), and thin sections with lead-citrate and uranyl-acetate.

From all cerebella the following areas were examined for Golgi cell counts: Lobus anterior, vermis and hemispheres of Lobulus II ; Lobus posterior, vermis and hemispheres of Lobulus IX ; Lobus nodulo-floccularis, vermis and hemispheres of Lobulus X.

Golgi cell counts were made according to the methods of Haug (1967a, b), using the Floderus correction (1944); shrinkage was determined according to the data of Palkovits, Magyar and Szentagothai (i971 a). Differences in cell density per unit volume are proved to be significant applying the t-Test (p < 0.01).

Results

Beside the Lugaro cells, the Golgi cells are the other larger cell t y p e wi thin the granular layer of the eerebel lar cor tex and are easi ly d i f ferent ia ted f rom the granule cells in Golgi impregna t ions (Fig. 1 a). W i t h the usual s ta ining methods for l ight microscopy including semithin sections, Golgi cells are easily recognized b y thei r large pale nucleus wi th character is t ic invaginat ions , the voluminous cell body and the d i s t inc t ly s ta ined Nissl granules (Fig. 1 b). In the electron micro- scope, Golgi cells are also easily ident i f ied by the large infoldings of the nuclear envelope, the voluminous cy top lasm and the d i s t r ibu t ion of cell organelles a round the nucleus and at the cy toplasmic pe r iphery (Fig. 1 e). This type of large Golgi cell mos t ly appears within the upper half of the granular layer, whereas smal ler Golgi cells wi th a s imilar nuclear s t ruc ture and a r rangement of cell organelles are more f requent in the lower half of the granular layer and in the medu l l a ry rays of the folia.

A first examina t ion of the semithin sections shows t ha t the Golgi cells in the vermal pa r t s of the nodulofloeeular lobe and also in the vermis of Lobule I X are obviously more numerous t han in the other pa r t s of the cerebellar cortex. Fur the r -

Distribution of Golgi Cells in the Cerebellar Cortex 221

Fig. 1. (a) Large Golgi cell close to the Purkinje cell layer in the cerebellar cortex of the cat. Golgi-Bnbenaite impregnation. X 500. (b) Large and small Golgi cell in the cerebellar cortex of rhesus monkey. The infoldings of the nuclear membrane are visible. • 1200. (c) Golgi cell in the cerebellar cortex of rhesus monkey. The cell is surrounded by granule cells. X 5300

222 W. Lange

Table 1. Number of Golgi cells per mm a in the human eerebellar cortex

V e r m i s Hemisphere

Lobus an~rior 271.11 189.91 (Lobulus II) • 22.34 -4-17.56 Lobus posterior 435.12 253.47 (Lobulus IX) -4-36.71 • 19.58 Lobus nodulo- 517.32 309.18 floccularis -4- 53.19 i 25.44

more, most of the light microscopically identified Golgi cells are located in the upper half of the granular layer close to the Purkinje cell layer. Before any quan- titative evaluations are presented, we wish to draw attention to the fact, that in the human material it is very difficult to distinguish the smaller Golgi cells from the granule ceils. Thus the smaller Golgi cells are probably not counted. The cell counts within 6 different areas of such human material, however, confirm the anticipation of a regional variation in the distribution of Golgi cells. In the nodulus, which phylogenetically is one of the oldest parts of the cerebellar cortex, the number of Golgi cells is higher than in all other parts. But in the vermis of Lo- bule I X (uvula) a fairly high density of Golgi cells was also found. The number of Golgi cells in the hemisphere of the nodulofloccular lobe and Lobule IX in all cerebella was significantly lower than in the vermis. Table 1 surveys regional differences in the distribution of Golgi cells in the human cerebellar cortex.

As shown in Table 1 the differences in the density of Golgi cells between the hemispheres and vermis of the nodulofloeeular and the posterior lobe are remark- able. In the anterior lobe, the differences between the vermis and hemispheres are not as striking, but are nevertheless significant (t-Test, p < 0.01).

In the non-human material, cell counts were performed on semithin sections. Because only two animals of each species were available to obtain the data in Table 2 the cell counts for both animals were averaged. With only two animals, nothing can be said about individual variation.

The cell numbers in Table 2 indicate that in the mammals investigated, as in man, there are remarkable differences in the distribution of Golgi cells in the cerebellar cortex. The highest density of Golgi cells as in man is found in the vermal parts of the nodulofloccular lobe and of lobulus IX. In all mammals, the diffe- rences between the vermal and hemispherical parts of the same lobe are significant. There are also significant differences between the vermal parts of the anterior and posterior lobe, because in the anterior lobe the density of Golgi cells is lower than in all other parts of the cerebellar cortex that were investigated. But attention should be focussed on another noteworthy feature. In man, the number of Golgi cells per mm a is very low in contrast to other mammals. There exists a positive correlation between the brain weight of the investigated animals and the number of Golgi cells per mm a. This means, that the cell density increases from man (with the highest brain weight) to the smaller animals such as the mole, the hedge- hog and the rat.

Distribution of Golgi Cells in the Cerebellar Cortex 223

Table 2. Number of Golgi cells per mm a in the eerebellar cortex of some mammals

Vermis ttemi- Vermis Hemi- sphere sphere

Rhesus monkey Lobus anterior 543.87 485.62 (Lobulus II) • • Lobus posterior 722.57 491.14 {Lobulus IX) • • Lobus nodulo- 739.25 620.55 floccularis • •

Crab eating macaque Lobus anterior 552.49 364.24 (Lobulus II) • • Lobus posterior 892.92 702.71 (Lobulus IX) • • Lobus nodulo- 1008.22 661.20 floccularis • •

Cat Lobus anterior 628.64 303.23 (Lobulus II) • • Lobus posterior 739.58 355.00 (Lobulus IX) • • Lobus nodulo- 702.60 525.10 floccularis • •

Ocelot Lobus anterior 743.78 615.81 (Lobulus II) • • Lobus posterior 895.57 721.19 (Lobulus IX) • • Lobus nodulo- 901.56 693.48 floecularis • •

Pig Lobus anterior 497.12 367.13 (Lobulus II) • • Lobus posterior 624.41 421.44 (Lobulus IX) • • Lobus nodulo- 680.91 447.23 floceularis • -V26.77

Rabbit Lobus anterior 1050.21 769.12 (Lobulus II) • i63.48 Lobus posterior 1346.04 902.29 (Lobulus IX) • • Lobus nodulo- 2174.37 1127.83 floecularis • 189.76 • 101.59

Opo88um Lobus anterior 636.04 576.87 (Lobulus II) • • Lobus posterior 961.46 532.50 (Lobulus IX) • • Lobus nodule- 1198.12 680.42 floccularis • •

Hedgehog Lobus anterior 1437.86 1075.76 (Lobulus II) • 131.23 • 125.50 Lobus posterior 1804.48 1425.49 (Lobulus IX) • • Lobus nodulo- 2277.72 1708.81 floccularis • •

Rat Lobus anterior 769.18 558.85 (Lobulus II) • • Lobus posterior 1050.21 695.19 (Lobulus IX) • 121.52 • Lobus nodulo- 1464.37 591.67 floccularis • 135.43 •

Mole Lobus anterior 1567.92 1109.26 (Lobulus II) • • Lobus posterior 1834.17 1480.00 (Lobulus IX) • • Lobus nodulo- 2410.93 1477.35 floccularis • •

Discussion

L a n d a u in 1928 first ment ioned the p robab i l i t y of regional differences in the a r r angemen t of granule cells in the cerebel lar cortex. Bu t in more recent studies, his f indings could not be confirmed {Jansen and Brodal , 1958). The resul ts of our quan t i t a t i ve s t u d y in m a n and 10 different m a m m a l s confirm the observat ions of J a k o b (1928) and Brodal and Drablos (1963) on the regional d i s t r ibu t ion of Golgi cells in the g ranu la r l ayer using quan t i t a t i ve da ta . Fu r the rmore , there are no t only differences in the d i s t r ibu t ion of Golgi cells between the ve rmal pa r t s of the anter ior and poster ior lobes of the cerebellum, which had been previous ly suggested b y these earl ier inves t iga tors : there are also r emarkab le differences be tween the

F

Corpus cereboll

Lob, i post,!

Lob, flocc, nod.

224 W. Lange

Fig. 2. Schematic diagram showing the distribution of Golgi cells in the mammalian cerebellar cortex. Note the high number of Golgi cells in the inferior vermal parts and the lower cell

density in the vermal parts of the anterior lobe and in the hemispheres

vermis and the corresponding hemispheres of each lobe. These findings are summarized in Fig. 2. From this diagram it is evident, that in the vermis of the nodulofloccular lobe and of lobulus IX, the number of Golgi cells is very high and becomes notably smaller in the vermis of lobulus I I in the anterior lobe. Bat there appear also to be differences in the hemispherical parts of the various lobes. While the number of Golgi cells in the flocculus is relatively high, it decreases in the hemispherical part of lobulus II.

Palkovits, Magyar and Szent~gothai (1972b) also determined the number of Golgi cells in the cerebellar cortex of the cat. But these authors did not demon- strate regional differences in their distribution. In addition, these investigators did not count the small Golgi cells, but only the larger ones. Consequently, their "total" number of Golgi cells per mm s is smaller than in our study. So the con- vincing scheme of Palkovits et al. (1972b) with a numerical relationship between Purkinje cells and Golgi cells of 3: 1 has to be slightly modified. A constant relation between Purkinje cells and Golgi cells can be averaged for the whole cerebellum, but it has to be determined for every region separately in view of the striking differences of Golgi cell density in various parts of the cerebellar cortex. Thus, when considering such numerical relation one must restrict oneself to one area or, if the total number of all Purkinje cells and of all Golgi cells are known, to one species.

From a neurophysiological point of view, we must draw attention to the op- timal ratio of Purkinje cells to Golgi cells, which would be close to 1:1. In man this ratio is 1:1.5. In the other mammals, this ratio is lower. Our calculations suggest the following ratios: rhesus monkey 1 : 1.85; cat 1 : 1.84 ; rabbit 1 : 1.85; hedgehog 1 : 1.94; rat 1 : 3.31 ; mole 1:2.17 ; opossum 1:2.68. In the other mammals, the total number of Purkinje cells could not be determined.

Distribution of Golgi Cells in the Cerebellar Cortex 225

However, with the increasing number of all cell types per unit volume in the cerebellar cortex from animals with a low brain weight to animals with a high brain weight (e.g. man), the number of Golgi cells also increases. One should point out that no linear increase is apparent in relation to brain weight. The hedgehog and the mole, with a low brain weight have a very large number of Golgi cells per unit volume, twice as in other species with a comparable brain weight such as the opossum. Probably this exception is due to the evolutionary level of these insectivores. Nevertheless, the relation of Golgi cells to Purkinje cells in these animals should not be considered exceptional because of the very high number of Purkinje cells also found in the hedgehog and mole brain (Lange, in preparation).

According to Palay and Chan-Palay (1974) Golgi cells receive afferents from the climbing and mossy fibres, from granule cells, and also from basket cells and stellate cells. The axons of the Golgi cells terminate upon granule cells at inhibitory synapses. Thus the Golgi cells are engaged in the cerebellar circuits of both afferent pathways and may modulate the input and output of the cerebellar cortex in many different ways. One can speculate that a ratio of Golgi cells to Purkinje cells approaching 1:1 probably provides for a better modulation of the cerebellar cortex than is possible when the disparity between the numbers of these two cell types is greater. Perhaps ratios approaching 1:1 include a higher evolutionary status of those brains in which it is found.

Finally, the results of Spacck, Parizek and Lieberman (1973) on the differential distribution of molecular layer Golgi cells, the results of Braak (1974) on the differential distribution of Lugaro cells and our findings demonstrate that, like the cerebral cortex, the cerebellar cortex exhibits distinct regional cytoarchitec- rural variations.

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