Functional details of the basal ganglia as related to the spatial organization of their fibers in cortex and thalamus.

This study compared the results of experimental-morphological and physiological studies in which facts were obtained regarding the functional and morphological heterogeneity of the basal ganglia. Experiments were done on dogs in order to study delayed responses and Hunterian delayed choice responses. Electrical and chemical stimulation of striopallidal structures and recording of spike activity in neurons were done in cats during the formation of conditioned reflexes. Morphological studies were done on cats and dogs by the technique of axon-terminal degeneration. On the basis of an analysis of our own data and data in the literature we have advanced the hypothesis that: 1)There is a correlation between the general features of the disturbance in higher nervous activity and the overlap of striopallidal projections onto cortical and thalamic structures; 2) in a series of cases the behavioral disturbance after shut-off or stimulation of the thalamic structures; 2) in a series of cases the behavioral disturbance after shut-off or stimulation of the basal ganglia can be correlated with the topical details of their projection onto cortical fields and thalamic nuclei.

[Functional significance of the spatial organization of efferent projections of the striopallidum to the cortex and thalamus]. / O funktsional'nom znachenii prostranstvennoi organizatsii éfferentnykh proektsii striopalliduma na koru i talamus.

A correlation has been found between spatial organization of efferent projections of the striopallidum to the cortex and the thalamus and the nature of behavioural reactions. A relative homogeneity of cellular structure of the striopallidal nuclei and a wide overlap of their efferent connections in the cortex and the thalamus are one of the causes of the common character of striate influences on behaviour. Differences of spatial organization of striate projections may be connected with functional heterogeneity of striate structures.

[Organization of the thalamic and cortical projections of the cat neostriatum]. / Nekotorye osobennosti organizatsii talamicheskikh i kortikal'nykh proektsii neostriatuma koshki.

The investigation has demonstrated that in the cat the nucleus caudatus and the putamen are projected on the cortex and thalamic nuclei of the ipsilateral hemisphere according to a certain topical principle characterized by both similarity in localization of projections of these two structures of the neostriatum and their difference. On the one hand, to the same fields of the cortex and the thalamic nuclei fibres from both structures of the neostriatum go, and on the other hand--a number of cortical zones and thalamic nuclei get projections either from the nucleus caudatus or from the putamen only. Owing to a certain organization of the connections studied, it is possible to consider them as the base of functional heterogeneity of the basal ganglia. Over-lapping of the cortical and thalamic projections of the nucleus caudatus and the putamen might explain common striatal effects on behavioral reactions.

[Caudate-cortical connections in the cat brain]. / Kaudato-kortikal'nye sviazi golovnogo mozga koshki.

By means of optical and electron microscopic methods, the cortical fields from the ipsilateral hemisphere was analysed in the cat after electrocoagulation of the dorsal part in the nucleus caudatus (NC). Degenerating axonal preterminals and terminals were detected in the preparations impregnated after Nauta--Gygax and Wiitanen's methods and in electronograms. To exclude degeneration of cortical and projective thalamic fibrillae from the great number of regenerated conductors, additional operations were performed on the same cats--thalamic and ventral NC nuclei were damaged and coagulative electrode was inserted into the dorsal NC a month before the last operation.

[Efferent projections of the ventral portion of the putamen to the frontal, parietal and temporal regions of the cat cerebral cortex]. / Efferentnye proektsii ventral'nogo otdela skorpuly na lobnuiu, temennuiu i visochnuiu oblasti kory mozga koshki

Following the electrolytic lesion of putamen (rostral and caudal parts of the ventral field) of the cat's brain, degenerating endings of axons in the cerebral cortex were revealed ipsi and heterolaterally in frontal sections of the brain impregnated after Nauta--Gygax and Wiitanen. The projections were organized topically: the rostal part of putamen was projected to anterior parts of the cortex (motor and premotor, orbito-insular and S zones), while the caudal part sended the fibres to the occipital and auditory fields of the cortex and S2 zone.

[Efferent projections of the caudate nucleus to the cerebral cortex in monkeys]. / Efferentnye proektsii khvostatogo iadra na koru golovnogo mozga obez'ian

The efferent direct connections of the head and tail of the caudate nucleus with the cortex of the ipsilateral hemisphere were studied in adult Macaca mulatta. Degeneration of endings in the frontal, precentral and postcentral convolutions was found ipsilaterally in sections of the brain impregnanted after Wiitanen after destruction of the caudate nucleus. The course of solitary fibres to sites of localization of degenerating endings was followed. as compared with the cat in which caudate-cortical projections had been established earlier, cortical zones with degenerated endings were located more discretely in Macaca mulatta.

[Topical characteristics of the organization of the strio-cortical tract in the brain of the dog]. / Topicheskie osobennosti organizatsii strio-kortikal'nykh sviazei golovnogo mozga sobaki

The study was carried out by the method of axo-terminal regeneration with impregnation of frontal sections of the brain with the Laidlaw liquid. It was shown that following a lesion of the dorsal and ventral area of the caudate nucleus in the dog's cerebral cortex correspondingly different amount of degenerating terminations of strio-cortical fibres could be revealed. These bonds were mainly directed into the VI and V layers of the cortex, namely into the frontal, precoronary, postcoronary, orbital and insular areas.