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Microglial cells play an important role in the pathophysiology of intracerebral haemorrhage. We have examined the possible influence of sevoflurane on the reactivity of microglial cells during intracranial haemorrhage.Forty adult male rats were divided into two groups. All animals were anaesthetized with fentanyl, dehydrobenzperidol and midazolam. In the experimental group animals additionally received sevoflurane 2.2 vol% end-tidal concentration. Intracranial haemorrhage was produced through infusion of blood into the striatum. The microglial cell population (numerical density of immunoreactive cells and their distribution) was assessed on days 1, 3, 7, 14 and 21 after producing a haematoma using antibodies OX42 and OX6.In the control group significant differences in the density of OX42-ir cells between 3rd and 7th (81.86 vs. 129.99) (95% CI: -77.99 to -18.25, P = 0.0035) and between 14th and 21st (105.36 vs. 63.81) (95% CI: 13.21 to 69.89, P = 0.006) survival days were observed. However, significant increase of percentage of amoeboid OX42-ir cells between 3rd and 7th (0.98 vs. 48.71) (95% CI: -52.17 to -43.30, P = 0.0001) and between 7th and 14th (48.71 vs. 58.47) (95% CI: -13.96 to -5.55, P = 0.0002) and then their decrease - between 14th and 21st (58.47 vs. 31.74) (95% CI: 22.52 to 30.93, P = 0.0001) days of observation were noted. In the sevoflurane groups OX42-ir cells were not found. On the 3rd day the density of OX6-ir cells in the sevoflurane group was significantly lower than that in the control group (12.39 vs. 34.57) (95% CI: -49.78 to -2.96, P = 0.02). The percentage of an amoeboid form of OX6-ir cells was significantly lower in the sevoflurane group than that in the control group (27.31 vs. 82.03) (95% CI: -72.52 to -36.92, P = 0.0001) (58.76 vs. 82.37) (95% CI: -38.81 to -8.41, P = 0.003) (42.87 vs. 81.55) (95% CI: -53.23 to -24.10, P = 0.0001) respectively for 3rd, 7th and 14th days of survival.Administration of sevoflurane during anaesthesia in animals with intracerebral haemorrhage evoked a decrease of activation of the microglial cells.

The retrograde axonal transport method was used to compare the topography and organization of the visual zone of the claustrum in rat, guinea pig, rabbit and cat. First, massive Fluoro-Gold injections were placed into the primary visual cortex and the secondary areas. Experiments showed differences in the location of the visual zone among the animals under study. In rat, the visual zone occupied the posteroventral part of the claustrum and spread to its anterior pole. In guinea pig, neurons projecting to the visual cortex were located dorsally in the posterior half of the claustrum. In rabbit, similarly to the rat, they were localized in the posteroventral part; however, they did not reach the anterior pole. In cat, neurons that project to the visual cortex were concentrated dorsally in the posterior fourth of the claustrum. In double-injection experiments, Fast Blue and Diamidino Yellow were placed into the primary and secondary visual areas in various combinations. The experiments showed that in the rat and the rabbit claustral neurons project to primary visual cortex (area 17) as well as to both secondary visual areas (areas 18a and b). Populations of neurons sending axons to the primary and secondary areas showed full overlap. The presence of double-labeled neurons indicates that some claustral neurons project both to the primary and secondary fields. In cat, neurons that project to the primary visual cortex appear to be clearly separated from those connected with the secondary visual area, as no double-labeled neurons were found. In all studied species, the double injections placed into the visual and primary somatosensory cortex did not result in any double-labeling neurons. Our results indicate that the location of the visual zone in the posterior part of the claustrum is a phylogenetically stable feature, whereas its dorsoventral shift as well as the extent toward the anterior pole is related to the particular species. The overlap of neurons projecting to the primary and secondary visual areas in the rat and rabbit as well as the separation of both projections in cat appear to reflect the higher degree of complexity of the visual system in the latter.

Methods of retrograde axonal transport were employed to evaluate the topography and overlap of claustroneocortical connections in the rat. Fluorescent tracers Fast Blue (FB) and Diamidino Yellow (DY) were injected simultaneously in various combinations into the motor, somatosensory, auditory and visual cortical areas. Experiments showed that claustroneocortical projections are organized in two main cortico-related zones: sensorimotor and visuoauditory. The sensorimotor zone occupies the anterodorsal part whereas the visuoauditory occupies the posteroventral part of the claustrum. Between these two main zones only a scanty overlap was observed. In the sensorimotor zone a large overlap between neurons projecting to the motor and somatosensory cortical areas exists. The visuoauditory zone is characterized by a full overlap of neuronal populations projecting to the visual and auditory areas.

In dogs under 17 years of age no amyloid deposits were observed in the claustrum. After that age amyloid deposits were found in all the brains studied. The number of amyloid deposits increases rapidly between 17 and 19 years of age. In none of the animals were neurofibrillary tangles found. However, in almost all claustra with amyloid deposits the number of neurones was smaller than in those without amyloid pathology. The loss of neurones resulted in a decrease in the volume of claustrum, which is about 22% smaller in dogs over 17 years of age than in younger animals. No considerable age-related differences were found in the average size of neurones and their nuclei.

Intracerebral haematoma was produced in 25 adult rats by infusion of 100 microl of autologous blood into the striatum. The animals' brains were removed at 1, 3, 7, 14 and 21 days after production of the haematoma. The TUNEL method was used to detect DNA fragmentation and TUNEL-positive cells were qualified. TUNEL-positive cells were already found on the first day of observation and were present for three weeks after haematoma production. These results provide evidence that programmed cell death is associated with intracerebral haemorrhage.

40 adult Wistar rats were divided into two groups depending on the applied anaesthesia. In both groups animals were generally anaesthetized with fentanyl, dehydrobenzperidol administered intraperitoneally and midazolam given intramuscularly. In the second group (SEVO) animals received sevoflurane of 2.2 vol% end-tidal concentration. Intracerebral haematoma was produced through infusion of 100 microl of autologous blood into the striatum. Each group was divided into five subgroups depending on the length of survival period: 1, 3, 7, 14, 21 days. The astrocytic population was studied by means of anti-GFAP staining. Stereological analysis was applied to estimate the numerical density of immunoreactive cells and the distribution of their types. On 7th day of observation the density of GFAP-immunoreactive astrocytes in SEVO was lower (p0,05) than that in the control group. In the control group, the increase (p0.05) of per cent of activated astrocytes between the 1st and 3rd survival day was noted, which remained at this level till the end of observation. In SEVO group, the increase (p0.05) of per cent of activated astrocytes between the 3rd and 7th day and the decrease (p0.05) between the 14th and 21st survival day were observed. During days of observation the per cent of activated astrocytes was lower (p0.05) in the SEVO group than that in the control group. Administration of sevoflurane during anaesthesia to animals with intracerebral haemorrhage has evoked not only the delay of the activation of astrocytes but also decrease in its level.

The shape of the inferior horn of the lateral ventricle has been investigated in 100 (50 right and 50 left) human brain hemispheres which were fixed in 40% formaldehyde solution and cut frontally. It has been found that the shape of the inferior horn depends on the course and depth of the collateral and occipitotemporal sulci. In most cases a part from two main ventricular surfaces: the hippocampal and superolateral, there is one surface more, either the inferior-collateral eminence (Type I--97% of cases in the posterior part of the inferior horn, 49%--in the middle and 42%--in the anterior part) or the inferolateral, adjecent to the occipitotemporal sulcus (Type II--0%, 26% and 35%, respectively). In a few cases both collateral eminence and inferolateral surface were present (Type III--3%, 2% and 6% respectively). In type IV neither collateral eminence nor the inferolateral surface appeared (0%, 23%, 17% respectively). The authors suggest to designate the inferolateral surface, not mentioned in the literature, as the occpitotemporal eminence (of the inferior horn).

Data obtained by using ultrastructural and morphometric approaches revealed three types of neurons in the cat visual claustrum. The most numerous were medium-sized and large ones. They formed 3/4 of the cell population. The ultrastructural properties of those cell types were largely similar. Their cell bodies were oval, round, fusiform or triangular and contained more or less indented nuclear envelope. The cytoplasm of those cells was characterized by a high concentration of subcellular organelles and particularly rough endoplasmic reticulum. The characteristic feature of those cells was a low nucleus/cell body area ratio (47 +/- 1% and 43 +/- 1%, respectively). The proximal dendrites of medium-sized cells were usually wide at the base, relatively short and tapering, whereas, those arising in the large cells were often thick and had a short tapering base. The neurons described above stained by Golgi impregnation method showed spines on their distal dendrites both under the light and electron microscopy. The retrograde axonal transport of HRP and WGA-HRP following injections into the visual cortex confirm that they are mainly projection cells which form the ascending limb of the claustrocortical loop. The third type of neurons formed a less numerous group of small cells which differed from the larger ones in various respects. They possessed the large nuclei with deeply indented nuclear envelope and comparatively a thim layer of cytoplasm poor in subcellular organells among which free ribosomes and mitochondria were common. The nucleus/cells body area ratio high (59 +/- 2%). In Golgi preparations their dendrites did not show spines. The dendrites originating from that type of neurons were thin, long and did not posses a wide tapering base. They are mainly claustral intrinsic neurons.

The claustrocortical connections in the rabbit were assessed for the first time by the method of axonal retrograde transport of two fluorescent tracers (Fast Blue and Diamidino Yellow). The material consisted of 23 adult New Zealand rabbits. Projection zones of spindle-like form, connected with the precentral, postcentral, temporal and occipital cortices have been delineated. They are organized topographically both in the anteroposterior and ventrodorsal direction. The precentral (motor) projection zone is localized in the anterodorsal part of the claustrum. It may be divided into two separate parts that project to the medial and lateral part of the precentral cortex. The large postcentral (somatosensory) zone occupies mainly the central part, whereas the temporal (auditory) and occipital (visual) zones are situated in the posteroventral part of the claustrum. The overlap of various claustral projection zones is differentiated, the largest being that of the somatosensory zones. In comparison to the results of study of claustral projection zones performed on other species, presumably on the rat and cat, its seems plausible to conclude that the extension of claustral projection zones and degree of their overlap in the rabbit represent an intermediate character.

The morphology of claustral neurons projecting to the motor, somatosensory, auditory and visual cortical areas in the rat was analyzed by means of combination of axonal retrograde transport and morphometric analysis. Fluoro-Gold (FG) injections placed into various cortical fields resulted in labeling in the claustrum four neuronal types: pyramidal with thick main dendrite, oval with a few thin dendrites spreading out in various directions, fusiform possessing two main dendrites arising from opposite poles of the cell body and polygonal. Pyramidal neurons prevailed in populations of neurons projecting to the motor cortex of the contralateral hemisphere. Oval neurons outnumbered other types in populations projecting to the somatosensory, auditory and visual cortical fields. The number of fusiform and polygonal neurons did not exceed at 12.5% together in any populations. Neurons projecting to the contralateral hemisphere were the largest claustral neurons (mean cross-section are 167.19 +/- 2.9 micron 2) whereas neurons projecting to the motor cortex where the largest claustral neurons projecting ipsilaterally (141.89 +/- 2.22 micron 2). There was no significant difference between neurons projecting to the somatosensory (113.46 +/- 1.9 micron 2) cortex and to the visual (111.8 +/- 1.4 micron 2) cortex whereas neurons related to the auditory are (95.98 +/- 1.75 micron 2) were the smallest claustral neurons. These observations pointed out that the morphology of claustral neurons is closely related to a cortical area to which they send axons.

Development and maturation of the basolateral complex of the amygdaloid body were studied in fetal and postnatal rat brains. In cresyl violet-stained sections the basolateral complex was distinguishable at the 17th prenatal day. On about the 14th postnatal day, it showed all the features of the adult structure. The acetylcholinesterase activity appeared in neuropil of the basolateral complex on the seventh postnatal day; it increased slowly up to the 60th day. After that age, the acetylcholinesterase activity was stable in all parts of the basolateral complex and corresponded to its cytoarchitectonic differentiation. Our results suggest that the process of maturation of the amygdaloid basolateral complex, being related to the ingrowing of the cholinergic fibers from the basal forebrain, lasts at least up to the end of the second month of postnatal life.

The topography and cytoarchitectonics of the claustrum as well as morphometric parameters of its neurons were studied in 10 human brains obtained from patients without any detectable neuropathological changes. We distinguished four parts of the claustrum: dorsal, orbital, temporal and paraamygdalar. The dorsal and orbital parts contain larger cells, than those of the temporal and paraamygdalar parts, although these differences were statistically non significant. The highest neuronal density was observed in the paraamygdalar part. The nucleus and nucleus@cell body area ratio was significantly smaller in the dorsal part than in other parts of the claustrum. We described three types of neurons in the claustrum: (1) medium-sized either fusiform or triangular cells with darkly stained cytoplasm; they predominate in the dorsal and temporal parts, (2) medium-sized as well as large cells, either multipolar or pyramidal-like with lightly stained cytoplasm; they are most numerous in the orbital and paraamygdalar parts, (3) small, multipolar or oval neurons with darkly stained ring of cytoplasm; these types of neurons are uniformly distributed throughout all parts of the claustrum. The subdivision of the human claustrum is in accordance with our observations that each of these parts possesses connections with different cortical regions.

Pathological changes in the claustrum and its main parts (dorsal, temporal, orbital and paramygdalar) were studied on ten brains of patients with Alzheimer's disease and five control brains. The brains after fixation in formalin were embedded in paraffin, coronal-8-micron-thick serial sections were cut and stained either with cresyl violet or with immunocytochemical methods for amyloid and tangles. Morphometrical studies were performed in all parts of the claustrum along its whole extension. The claustrum in control brains was free of neurofibrillary and amyloid pathology except for one case with few senile plaques in the paramygdalar part. In AD affected brains the most severe changes were found in the paramygdalar part connected with the entorhinal cortex (neuronal loss -46%; 698 +/- 244.6 neurofibrillary tangles per mm3, tangle/neuron ratio -6.8 +/- 2.4%). In other parts of the claustrum related mainly with the neocortex pathological changes were significantly less expressed. As pathological AD type alteration affects severely practically the whole hippocampal formation, including the entorhinal cortex, the extensive neuronal pathology of the paramygdalar part of the claustrum is probably related to this process and may deeper memory dysfunction.

The morphometric analysis of some hypothalamic nuclei was performed on 20 brains of subjects of both sexes aged from 29 to 79 years. They were divided into two groups: below and above the age of 60. Supraoptic (SON), lateral tuberal (LTN) and lateral mammillary (LMN) nuclei were investigated. In the group of aged subjects a decrease in cross-section area of neuron nuclei was observed in all investigated structures, expressed most in the LTN. A considerable increase in the neuron density with age was found in the LTN. The size of neuron cell bodies and the number of neurons did not change significantly with age in any of the investigated nuclei.

Methylazoxymethanol acetate (MAM) is a substance that inhibits migration of neurons in the embryonic brain. After intraperitoneal injection of two different doses of MAM to pregnant rats, microcephaly with or without complete development of the cerebral cortex was observed in every litter. High MAM doses (30 mg/kg) resulted in the lack of superficial layers (II-IV) of the cerebral cortex when the deep layers (V, VI) were seen. The claustrum was present but composed of loosely packed, medium-size, triangular or fusiform neurons with anarchic oriented long axes. After administration of low MAM doses (14 mg/kg) two different parts (medial and lateral) of the insular claustrum were observed. Our results suggest that neurons of the insular claustrum create two different subpopulations of cells, which were similar to that observed in primitive insectivore (e.g., hedgehog), but fuse in development.

Cytoarchitectonics of the lateral tuberal nucleus--a phylogenetically new hypothalamic structure--was investigated using morphometric methods. The most characteristic feature of the human lateral tuberal nucleus is an extremely great variability of its shape and segmentation. The lateral tuberal nucleus consists mostly of several separated neuronal groups; in each brain the arrangement of these groups is different. In macaca the lateral tuberal nucleus is a single elongated neuronal structure much less variable than in man. The human LTN is approximately ten times larger than that in macaca, but the number of neurons is only about four times higher due to a lower neuronal density. The lateral tuberal nucleus both of man and macaca is a homogenous neuronal population with a very low coefficient of variability of cross-section neuronal area (30% and 24% respectively). The size of neuronal bodies in the lateral tuberal nucleus is about 42% smaller in macaca than in man. However, the size of neuronal nuclei is slightly (15%) bigger and the nucleus/cell body area ratio is about twice as high in macaca as that in man (40% and 21% respectively).

The parahippocampal (ventral) surface of the lateral part of the transverse fissure (LTF), formed by the parahippocampal gyrus, was examined in 53 human brain hemispheres without pathological changes. Cytoarchitectonics of this region was studied on the frontal histological sections stained either with cresyl violet or with Weil method. Four types of the shape of the parahippocampal surface of LTF were distinguished. In type 1 the surface is either flat or elevated in its medial part (medial eminence; 34.0%). In type 2 the surface is elevated in its lateral part (lateral eminence, 24.5%). In type 3 there are two eminences--the lateral and the medial; both of similar height (20.8%). In type 4 the lateral eminence is distinctly higher than the medial one (20.7%). The eminences contain cytoarchitectonically different structures. The lateral eminence is formed mainly by the subiculum and CA1 area, the medial by the presubicular region. The shape of the parahippocampal surface of LTF may be of importance in assessment of the Alzheimer's disease pathology.

Investigation of the dog's insular claustrum was performed using morphometric methods. The brains of 14 dogs (7-14 year-old) were studied. The size, shape and density of neurons are different in various parts of the insular claustrum. The posterior part, related to the visual system, is heterogenous and possesses medium-sized and small densely packed neurons, the average cross-sectional area of cell body being 175.8 +/- 45.5 micron2. The similar average cross-sectional area of cell body (174.1 +/- 55.3 micron2) was found in the central part of the insular claustrum. However, neuronal architecture is here less heterogenous and neurons are less densely arranged. The anterior part, connected mainly with the frontal and motor cortex, is more homogenous and contains loosely arranged neurons of a rather large size (average size--198.7 +/- 53.46 micron2).

The hippocampal formation was studied in 5 brains of younger (29 to 52 years of age) and 6 brains of elderly (61 to 89 years of age) subjects without signs of dementia, as well as in 11 brains of patients with Alzheimer's disease (65 to 91 years of age). The 8-microns-thick sections were stained either with cresyl violet, Weil method or with immunocytochemical methods for amyloid (4G8) and neurofibrillary tangles (Tau-1). Cell bodies, senile plaques and tangles were counted in all brains. In brains of patients with Alzheimer's disease a significant neuronal loss (about 56%) was observed in the second layer of the entorhinal cortex. The tangles/neurones ratio was very high (62.79.1%) in this layer. A great number of senile plaques were present in the whole hippocampal formation, especially in the molecular layer of the dentate gyrus (22.91.5 plaques/mm2) which is the termination zone of the perforant path. It seems therefore, that pathological alterations in Alzheimer's disease disrupt the main input to the hippocampal formation. In "physiological" ageing we did not observe changes in the density of neurones, although single tangles and plaques were found in all hippocampal areas. In elderly individuals 3.81.3% of neurones of the second layer revealed neurofibrillary pathology; a few plaques were found in various areas of the hippocampal formation. These observations may suggest only a slight decrease in number of neurones in the hippocampal formation. However, these changes cause a slight impairment of memory and learning often found in elderly individuals without dementia.

The claustrum is a large subcortical structure that in animals possesses extensive connections with almost all regions of the cerebral cortex. Because there are no data that support the presence of claustrocortical connections in human brain, the main aims of the present study were to confirm the existence of these connections in the human brain. Five controlbrain and nine brains with bilateral and large ulegyria were studied. Severe neuronal loss in the anterior part of the claustrum was observed after pathological lesions that involved the frontal cortex. Pathological changes localized in the parietal and occipital cortices caused neuronal loss in the central and posterior part of the human claustrum. These findings suggest that the human claustrum is dependent on the neocortex and that, as in animals, it possesses extensive connections with the cerebral cortex that are topographically organized. The anterior part of the claustrum is connected with the frontal cortex, and the central and posterior parts with the parietal and occipital cortices.

The morphology of the claustrum in Galloway syndrome was investigated. Galloway syndrome is a rare autosomal recessive disease that causes microcephaly and is associated with kidney pathology. The brain examined was small, and the external surface of the hemispheres was lissencephalic, with an abnormal gyrification pattern. The whole cerebral cortex showed severe pathological changes, but the most affected area was the cortex lying on the medial aspect of the temporal lobe, especially the entorhinal cortex. In addition, the paraamygdalar and temporal parts of the claustrum were intensively changed. These results may confirm the opinion that the claustrum is a cortico-dependent structure and that the limbic cortex receives large projection from its ventral parts.

Post-mortem MRI (magnetic resonance images) studies followed by histopathological examination were used to study the size and the shape of the lateral part of the transverse fissure of the brain in seven individuals with Alzheimer disease (AD) and five controls. In control brains, the lateral part of the transverse fissure is a narrow cleft protruding laterally as choroid and hippocampal recesses. In AD-affected brains, the lateral part of the transverse fissure becomes a large subarachnoid space as a result of different degrees of atrophy of various hippocampal and parahippocampal structures. Our findings directly indicate the relationship between changes in the hippocampal and parahippocampal structures and the size of the lateral part of the transverse fissure. Sector CA1, the subiculum, the entorhinal cortex, and the parahippocampal isocortex are the most affected, whereas the dentate gyrus is much less affected. Adjacent thalamic structures, which are less vulnerable to the AD pathology, do not appear to contribute to transverse fissure changes. The size and the shape of the lateral part of the transverse fissure of the brain in AD reflect the atrophy of the hippocampus and parahippocampal structures.

Studies of aged animals and aging humans have revealed numerous age — associated decrements in brain functioning. Foremost among behavioral changes are the declines in memory functioning. While animal studies have linked many of these aging changes to brain alterations, very little direct evidence is available for the human. By and large, our current understandings suggest that damage to the hippocampus is at least in part related to these age-related memory changes. In Alzheimer’s disease (AD) many of these age-related behavioral changes are markedly exacerbated and there is clear evidence for extensive neuropathological involvement of the hippocampus and associated regions.

The cytoarchitectonics of the nucleus of the lateral olfactory tract (NLOT) was studied on Nissl stained sections in 6 brains of adult Wistar rats by using morphometric methods. The neuronal density of layer III (11,866 +/- 547 mm-3) is on average about three times smaller than that of layer II (30,947 +/- 1110 mm-3). The average cross-section area of neurons in layer III (254.3 +/- 3.8 microns2) is about twice as large as that of neurons in layer II (115.8 +/- 0.8 microns2). The layer II is rather homogenous in contrast to layer III which possesses neurons of various size. Other morphometric parameters of layer II and III are also different.

The claustra of 9 species of Insectivora (Sorex araneus, Sorex minutus, Tenrec ecaudatus, Solenodon paradoxus, Neomys fodiens, Erinaceus europaeus, Talpa europaea, Desmana moschata, Potamogale velox) were investigated. In all examined animals we found two parts of the insular claustrum: the main part called by us the pars principalis and more medially situated lamina profunda claustri. In the "basal" Insectivora the main part is in close contact with the layer VIa of the neocortex. In some more developed "basal" and in all "progressive" Insectivora the area capsularis appears. Dorsolaterally it separates the main part of the insular claustrum from the neocortex and possesses, besides neurons, also numerous fibers of the extreme capsule. The above data strongly suggest that in the phylogenesis the insular claustrum originates from the cortex from which it gets separated by the extreme capsule. Lamina profunda claustri is rather a narrow band of neurons situated on the medial side of the pars principalis and mostly separated from it by a thin lamina of white substance. Lamina profunda is continuous with the layer VIb of the neocortex.

Unilateral, left electrocoagulative septal lesions of the rat brain were performed. Acetylcholinesterase and choline acetyltransferase activities in the left and right hippocampi were measured 6–8 and 14–17 days postoperatively. Small lesions, damaging mainly the nucleus lateralis evoked a small (10–20%) decrease in the activity of both enzymes on the ipsilateral and side a tendency to an increase in the enzymatic activity on the contralateral side. No differences were observed between values obtained on the sixth-eighth and the fourteenth-seventeenth days after the operation. Larger lesions, including the nucleus fimbriatus and the nucleus of the diagonal band evoked on the sixth-eighth day a decrease (40–50%) in the activity of both enzymes on the ipsilateral side, but on the fourteenth-seventeenth day a significant recovery in the enzymatic activity was noted. Contralaterally, following larger lesions, an initial decrease on the sixth-eighth day in choline acetyltransferase activity was followed by an overshoot in comparison to controls on the fourteenth-seventeenth day; acetylcholinesterase activity remained unchanged on the sixth-eighth day, but also surpassed the control value on the fourteenth-seventeenth day. It is suggested that the post-lesion changes in enzyme activity in the ipsilateral hippocampus occur mainly within the cholinergic system, while in the contralateral hippocampus they may be the result of damage to non-cholinergic fibres followed by sprouting of cholinergic axons.

Ipsi- and contralateral cortical somatosensory evoked potentials (SEP) were recorded following median nerve stimulation in 12 patients with unilateral brain lesions and in 5 healthy subjects. Computed tomographic scans of brain were performed on admission. In all patients with lesions of the claustrum there was absence of SEP contralateral to the side of the lesion and ipsilateral to the stimulated nerve. This phenomenon did not appear in our material following lesions involving other structures e.g. thalamus or somatosensory cortex. Our observations suggest that the claustrum may influence deeply the contralateral somatosensory cortex. This may be due to the fact that a large part of the claustrum is involved in transmission of the sensory information from receptors to the somatosensory cortex.

Cyto- and myeloarchitectonics as well as acetylcholinesterase activity of the nucleus limitans thalami--an important part of the nociceptive system--were studied in insectivora (Sorex araneus, Erinaceus europaeus, Talpa europaeus), rat, rabbit, cat, monkey and man. Our results suggest that nucleus limitans is phylogenetically a rather new structure. In insectivora and in the rat we could not find any evident group of neurons resembling nucleus limitans. In the rabbit and cat nucleus limitans is composed of few layers of elongated cells. In macaca and man it is a larger, more complicated structure possessing various types of neurons, and arranged into many layers.

On the basis of retrograde horseradish peroxidase transport from nuclei ot the amygdaloid body of the rat to the thalamus, it was found that several groups of thalamic nuclei send fibers to the amygdala. These are: (i) nuclei of posterior region of thalamus and neighboring area of the tegmentum - peripeduncular nucleus, suprageniculate-limitans nucleus, (ii) midline nuclei - paraventricular nucleus, parataenial nucleus, nucleus reuniens, (ii) intralaminar nuclei - central medial nucleus, parafascicular nucleus, (iv) medidorsal nucleus. There are two main systems of thalamoamygdaloid connections. One of them arising in the posterior region of the thalamus terminates in the lateral nucleus of the amygdala and the lateral part of its central nucleus. The other system begins in the intralaminar and midline nuclei and in the mediodorsal nucleus of the thalamus. It reaches the remaining nuclei of the amygdala. Amygdalopetal connections of the interlaminar and middline nuclei of the thalamus, especially those arising in the paraventricular and parataenial nucleus, are mostly bilateral.

The morphology of synapses in the amygdaloid nuclei was studied in 10 cats. On the basis of the percentage of axon terminals with flattened vesicles (F-type) nuclei were distinguished, in which these terminals are as sparsely distributed as in most areas of the central nervous system, from other nuclei in which they are abundant (about one-third to one-half of all synaptic boutons). The lateral, basal dorsal and basal ventral nuclei belong to the first, the medial and central nucleus and the anterior amygdaloid area--to the second group. The cortical nucleus, which generally has a small number of boutons of F-type has some parts seemingly belonging to the first, and others to the second group. In all amygdaloid nuclei axon terminals of F-type form symmetrical synaptic contacts. In nuclei with a low percentage of F-type terminals these boutons are predominantly small and synapse either with perikarya or with large dendrites. The amygdaloid nuclei having numerous F-type terminals contain not only small but also larger terminals with flattened vesicles. Both, the larger and smaller axon terminals form in these nuclei synaptic contacts with various parts of dendrites even with very small ones and with dendritic spines. The subdivision of amygdala into two parts, one with a low and another with a high number of F-type boutons would seem to support the hypothesis that amygdala may be subdivided physiologically into a dorsomedial--"excitatory" and basolateral--"inhibitory" portion.

The localization of acetylcholinesterase (AChE) activity in the nuclei of the amygdaloid body of man was studied by Gerebtzoff's modification of Koelle's acetylthiocholine method on 10 human brains. To compare the histochemical results with the cytoarchitectionics, additionally sections from 10 human brains were stained with cresyl violet. The intensity of AChE activity in the different amygdaloid nuclei varied widely. The high AChE activity occurred in the basal lateral nucleus and in the lateral part of the central nucleus. Very little activity was found in the medial nucleus and in the intermediate part of the central nucleus. All remaining nuclei showed AChE activity of moderate intensity. In almost each amygdaloid nucleus, differences of AChE activity among various areas were observed. In the amygdala of man all nuclei described in animals were found except nucleus of the lateral olfactory tract. Most of the human amygdaloid nuclei show more differentiated structure than in lower mammals in terms of not only cytoarchitectonic subdivision, but also in the intensity of AChE activity.

Horseradish peroxidase (HRP) was injected to various parts of the amygdala in 50 rats. Retrograde axonal transport revealed that tegmental areas containing biogenic amines: dorsal and median raphe nuclei, locus coeruleus and ventral tegmental area, project diffusely to various amygdaloid areas. Moreover, HRP labeled cells were found in the parabrachial nucleus (following injection of the lateral amygdaloid nucleus) and in tegmental dorsolateral nucleus (after injection of the central nucleus of amygdala).

The localization of neurons from which the projections to other amygdaloid nuclei arise was studied using the retrograde transport of horseradish peroxidase. It was found that the basal nuclei (dorsal and ventral) appear to be the main source of intraamygdaloid connections; they project to the central, medial and lateral nucleus of the amygdala. The medial and the central nucleus receive the most intraamygdaloid connections: the medial--from the basal dorsal, basal ventral, posterior part of the cortical nucleus and from the nucleus of the lateral olfactory tract; the central nucleus--from the basal (dorsal and ventral) nuclei and from the nucleus of the lateral olfactory tract. The afferent intraamygdaloid connections of the cortical and lateral nucleus were also found. These results are discussed with reference to the physiological differentiation and hypothalamic afferents of the amygdaloid body.

Injections of tritiated amino acid into the pretectothalamic border area of cats resulted in the appearance of numerous silver grains in the ipsilateral claustrum. The accumulation of grains was especially abundant in the dorsomedial area of the central part of the claustrum. These results indicate the presence of substantial projection from the pretectothalamic border area to the claustrum. It may be assumed that these projections belong to the somatosensory system, since they connect mainly di(mes)encephalic nuclei, receiving largely the somatosensory input, with the somatosensory part of the claustrum.

Experiments were performed on brains of 15 cats with the use of horseradish peroxidase (HRP) retrograde transport method. After injections of HRP to the insular cortex, relatively great numbers of labeled neurons were found in all main nuclei of the amygdaloid body. After injections to the anterior part of the granular insular cortex numerous labeled neurons were located in the lateral, central lateral, basal dorsal and basal ventral nucleus of the amygdaloid body. Injections to the agranular insular cortex labeled neurons in the lateral, basal dorsal and basal ventral nucleus and in the claustrum prepiriforme. These results indicate the presence of large projections from vast areas of the amygdaloid body to the agranular insular cortex and the anterior part of the granular insular cortex.

The insular claustrum of the cat was studied using Kopsch modification of the Golgi technique. Neurons with or without dendritic spines were found. Among spiny neurons large pyramid-like cells with one main dendrite (S I type) appeared most frequently. Spindle-shaped neurons with two main dendrites (S II type) and multipolar ones (S III type) occurred much less frequently. Two types of aspimny multipolar neurons were found-larger (A I type) and smaller (A II type). Both were observed only in the posterior areas of the claustrum, mainly in its visual part. In the narrower regions of the claustrum, especialy in its anterior and posterior part, the dendritic fields of neurons were mostly arranged parallel to the surface of the claustrum. Centrally in the broader intermediate part of the claustrum long axes of neurons were oriented in various directions.