Morphological evolution of the neurons in the rat's inferior colliculus.
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Biomedical subjects
Publications and source records attributed to V Meininger.
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The systematic pathological study of 500 patients with intracranial hemorrhages (ICH) [341 (68 P. 100) CEREBRAL HEMORRHAGES (C.H.); 119 (24 p. 100) meningeal hemorrhages (M.H.); 39 (7,8 p. 100) subdural hematomas (S.H.) and, at last, one extradural hematoma] has been practiced. Those cases were issued primarily from neurological and, at a lesser degree, from neurosurgical departments. Etiological data, complications, associated findings and causes of death have been analysed. High blood pressure is the main etiological factor in C.H. This is confirmed by the statistical comparison between the incidence of this factor in our material and in the whole French population. However, nearly 50 p. 100 of ICH occuring in normotensive patients are C.H. The incidence of cirrhosis is much higher in our study than in other reports from the literature. The frequently associated high blood pressure does not seem to enhance the incidence of CH in patients with liver cirrhosis. Although this last factor can be found alone, its real etiological importance in CH cannot be assessed on account of the lack of data concerning the incidence of liver cirrhosis in the French population. The incidence of anticoagulant therapy is high in S.H. On the contrary, this factor does not seem to enhance the risk of high blood pressure induced C.H. The traumatic etiology of S.H. is significantly higher than the anticoagulant therapy etiology which, however, is very high in our study.
The authors report 5 cases of avoiding phenomenon of the hand from parietal lesions. Four of these patients were operated for intractable epilepsy, from a parietal cortectomy that implicated a certain amount of white matter. The avoiding phenomena observed are analyzed as elementary motor perturbations rather than a disturbance of motor comportment. The authors distinguish two types of avoiding phenomena: 1--Avoiding phenomenon of dystonic type occurs during any motor activity and persists during all its development. It is probably related to the removal of the cortex of the post-central gyrus and of the anterior part of the superior parietal lobule; 2--The initial avoiding phenomenon is brief and occurs only at the beginning of the movements which implicate solely the upper limb; it seems related to the removal of the internal part of the superior parietal lobule that corresponds approximately to areas 5 and 7 from Brodmann. Some hypotheses are discussed concerning the possible physio-pathological mechanisms of these disturbances.
The motoneuronal organisation of the anterior horn with respect to the peripheral nerves, is still imprecise due to methodological problems. The chromatolytic and Golgi methods have furnished some fruitful but incomplete data. The retrograde transport of horseradish peroxidase permits to obtain both the topography of cells and their dendritic tree. With such a method we studied the cervical enlargment of the rat's spinal cord. Each nerve is in relation with a column of motoneurons whose both the metameric extension and the exact topography in the anterior horn have been defined. An histogram of the cell volumes has been performed for some nerves. These data permit to discuss the possible significance of the topographical separation of the cells related to the girdle with those in relation with the distal part of the upper limb. The histogram shows that the small cells, claimed to be gamma motoneurons, are much more numerous than generally supposed. The significance of the dendritic tree, which seemed oriented selectively in the cranio-caudal axis, is discussed.
Two different functional zones may be described in the superior colliculus. The superficial layers receive retinal and cortical fibers, the deep layers are a multimodal center and are implied in the oculo-motor control mechanisms. The aim of the present study has been to use network analysis in order to quantify the cell types of the deep layers of the superior colliculus in Man. 50 Golgi impregnated cell have been drawn in the three plans of space. Topological analysis permits to emphasize the existence of two different cell types: collaterally-branched cells or CB cells, and dichotomously-branched cells or DR cells. Quantitative analysis of the dendritic arcs has shown the spatial orientation of the dendritic tree. The proximal dendrites of DR cells are in the horizontal plane, the terminal dendrites are in the vertico-frontal plane. This difference seems to be due to different functional afferences.
The exact localisation of the motor pools of anterior horn providing the different nerves of the brachial plexus remains unclear. The data obtained have been furnished by different methods: Nissl methods furnish cytoarchitectonic data -- Golgi methods furnish dendro-architectonic data. The topographical data were obtained by the chromatolytic modifications of the moto-neurons after a peripheral nerve injury. The recently used method of the retrograde transport of HRP permits to get information about the exact localisation and the dendritic extent of the neurons of a motor pool related to a particular nerve. We have studied the localisation of the nerves of the brachial plexus in the cervical enlargement of the spinal cord. We have determined the exact extent of the different motor pools in relation to each nerve. It seems that two different regions may be recognized in the anterior horn: a ventro lateral one in relation with the girdle muscles and a dorso lateral region related with the more distal muscles of the anterior limb.
Bilateral tactile aphasia was exhibited by a patient who was operated upon for a left parieto-occipital haematoma. Neuropsychological investigation established the following points: (1) the patient, in whom no expressive or receptive dysphasia could be found, misnamed objects when they were presented to him tactually, whereas he almost always gave the correct name when they were presented visually or auditorily; (2) the naming disturbance was identical when the object was presented to the left hand or to the right hand; (3) not only did the patient have no sensory deficit, but he could give unquestionable proof of correct tactile identification by using the objects presented to him tactually; (4) the defect appeared in the verbo-tactile as well as in the tacto-verbal direction; (5) it was not restricted to the name of the object since the patient was unable to describe, without making dysphasic errors, the morphology or usage of objects presented to him tactually; (6) the tacto-verbal dysfunction did not result from a tacto-visual impairment. Computerized tomography scans showed that: (1) there was no evidence suggesting a lesion of the right hemisphere, nor of the corpus callosum; (2) the left lesion involved the angular gyrus, the posterior part of the second temporal convolution, the inferior longitudinal fasciculus, the geniculostriate fibres and some fibres of the tapetum.
The present study gives an histometric analysis of cells in the different subdivisions of the inferior colliculus. The use of principles and methods of stereology allows the definition of various cellular parameters, i.e. nuclear and cell volume, nuclear and cell profile areas, nuclear diameter, volume proportion of perikaryon, nuclear/cytoplasmic volume ratio and nuclear packing density. Our data confirm the existence of at least 3 parts in the inferior colliculus of the cat, namely: the ventral, the dorso-medial and the lateral parts. We furnish the various parameters which permit the characterisation of cells in these different parts. The dorso medial part or region appears to be composed of numerous cells characterized by their small volume and their high nuclear/cytoplasmic volume ratio. The ventral region seems to be distinguished by its scattered cells, characterized by their large volume and their low nuclear/cytoplasmic volume ratio, whereas the lateral region appears as an intermediate one with scattered cells of low volume. It seems notable that these cytoarchitectonic subdivisions fit well with the functional subdivision since the dorsomedial region receives cortical fibres, the ventral region receives cochlear fibres and the lateral region receives both cortical and cochlear fibres.
Three patients with well-mapped, circumscribed ablations of the medial part of the frontal lobe are reported. A specific clinical evolution in 3 stages was observed: (1) post-operatively there was global akinesia, more prominent contralaterally, with an arrest of speech; (2) recovery occurred suddenly but even then there was severe reduction of spontaneous motor activity contralaterally, an emotional type facial palsy and a reduction of spontaneous speech; (3) long after the operation the only sequela was disturbance of the alternating movements of the hands. The anatomical basis of these disorders appears to be a lesion of the supplementary motor area (SMA). Three main points have been discussed, namely: (1) the nature of the motor disorder which may be a disturbance of the function of the SMA in initiating and sustaining spontaneous and automatic motor activity; (2) the nature of the arrest of speech which appears not to be aphasic; the studies reported in the present paper do not support a left cerebral dominance for the SMA as suggested by previous studies; (3) the method of clinical examination appears to be important in distinguishing between spontaneous and voluntary motor and speech performance. Differences in method may account for differences between our findings and those reported in previous studies.
The network analysis methods have been applied to study the neurons of the medial bulbo pontine reticular formation in the cat. The bifurcation ratio allows isolation of two different cellular patterns: collateral branched cells or CB type, and at random pendant vertices dichotomously branched cells or DA type. The morphologic features of CB cells lead to the assumption that these cells have an integrative function. The topographic distribution of the two cells types seems to vary in the different parts of the reticular formation and should argue for the fact that the reticular formation represents an aggregation of several discrete anatomical units.
Two different types of protoplasmic astrocytes were studied by scanning transmission and conventional electron microscopy in order to determine the exact nature of the aspect described by Chan Palay and Palay as velate astrocyte. This study provides new data about the usefulness of S.T.E.M and brings into question the results of the Palays.
A network analysis of dendritic fields of the cells of the inferior colliculus has been performed in the adult cat. The cells of the dorso-medial nucleus have a smaller volume, less terminal segments and more dendritic spines than the cells of the ventral lateral nucleus. The bifurcation ratio of the different cells makes it possible to separate two different types of cells: order 2 cells with a strictly monochotomous branching on random segment and order 3 cells which dendrites grown by terminal branching on random pendant arcs.
As a result of 6 cases of frontal tumour presenting central facial paralysis with inverse dissociation this symptom was investigated in patients subjected to cortical excisions for intractable epielpsy. A study of 8 cases of frontal cortical excision, 6 of them affecting the internal and posterior portion, and two the prefrontal region, has provided evidence of a link between inverse automatic-voluntary dissociation facial paralysis and lesions affecting the Penfield supplementary motor area. In such cases, facial palsy is usually associated with motor disorders in the limbs, the most characteristic of which is unilateral motor under-utilisation. The possibility of inverse dissociated facial paralysis occurring as a result of a rostral premotor lesion cannot be ruled out in our present state of knowledge.
A comparative study of "normal" and "improperly oriented" pyramidal cells has been performed in the medial frontal lobe cortex of the monkey (Macacus Irus). The comparison of the observed number of topological types for each group of dendrites shows that the apical dendrites of each type of cells have a different growth. The apical dendrites of the normal pyramidal cells grow by monochotomous branching on random segments and have much more spines on the first order segments, the apical dendrites of the improperly oriented pyramidal cells grow by branching on pendant arcs (terminal growth model), and have fewer spines. The functional signification of these differences remains actually obscure.
The comparative study by network analysis of the dorso-median nucleus of the inferior colliculus has been performed in the adult and new born cat, the adult rat and the adult monkey. For each animal, the two previously recognized types of cells have been identified. However the number of each type of cells is different. The 2 order cells have the same volume in the rat, the adult cat and the monkey. The 3 order cells are larger in the monkey and the cat than in the rat. The number and the volume of the different types of cells is similar in the ventro-lateral nucleus of the adult cat and in the dorso-medial nucleus of the new born cat.
Pure dural arteriovenous fistulas are still not properly understood, and pose problems wich are far from being resolved. Among these, dural fistulas with cortical venous drainage represent a very special entity since they alone are expressed clinically by a neurological brain syndrome. Diagnosis is difficult and mistakes can be made as it is only by means of hyperselective arteriography of the branches of the external carotid that an accurate diagnosis can be made. However, their diagnosis assumes considerable importance since surgical or radiological treatment of hese fistulas brings about complete disappearance of clinical symptoms.
Scanning transmission electron microscopy of the dendritic spines of multipolar neurons in the cat inferior Colliculus was achieved on Golgi semi-thin sections. The three basic types of dendritic spines (ST, MS, TH) were identified. Scanning transmission electron microscopy provides a reliable method for a three dimensional view of these structures at high resolution and consequently a more accurate appreciation of their size. In addition, it could prove very useful in the quantitative analysis of the dendritic spines.