[Comparative analysis of the quantitative characteristics of the corticothalamic projections of the parietal cortex areas 5 and 7].

Relative number of the corticothalamic efferents after local coagulation of the parietal cortex areas 5 and 7 was studied. It was shown that areas 5 and 7 were maximally represented in the thalamic reticular, parafascicular nuclei and zona incerta. The number of the efferent fibers projecting from area 5 to the mentioned nuclei was greater than those from area 7. Projection of area 7 to lateral posterior nucleus was greater than that from area 5. The number of afferent fibers of the parietal cortex that terminated in the central lateral, ventral anterior nuclei and pulvinar was insignificant. It was suggested, that the predominant maximal projection of areas 5 and 7 on thalamic reticular, parafascicular nuclei and zona incerta may be dictated by the necessity of inhibitory control of descending corticothalamic influences.