[Efferent connections of various parts of the orbitofrontal cortex with thalamic structures in cats]

By means of impregnation methods of Fink-Heimer and Kawamura-Niimi in 29 cats after unilateral extirpation of various parts of the orbitofrontal cortex (middle part, superior and inferior areas of the dorsolateral part of the proreal gyrus, anterior area of the orbital gyrus) connections with various groups of the thalamic nuclei have been studied. Essential differences have been revealed in projections of various parts of the orbitofrontal cortex to specific, nonspecific, associative and limbic nuclei of the thalamus. The most distributed system of the subcortical projections has the orbital gyrus cortex. Connections of the cortex in the superior and inferior areas of the dorsolateral part of the proreal gyrus are well manifested, the connections of the superior area being less prevalent than the inferior ones. The cortex of the medial part in the proreal gyrus has connections mainly with the subcortical limbic formations. Thus, the orbitofrontal cortex in the cat possesses a system of topographically organized, to some extent selective monosinaptic connections practically with all nuclear groups of the thalamus and influences upon the function of the most of the important subcortical structures.