Comparative study of the neuronal structure of the neostriatum in birds with different extrapolation capabilities

A comparative study of the neuronal structure of neostriatum in crows possessing a great capacity for extrapolation of the movement direction of an alimentary stimulus, and in pigeons deprived of it, did not reveal any fundamental differences in the size of cells, the number of dendritic endings and dendritic ramifications. Differences were observed in the neuronal morphology. In the crow neostriatum neurones, the dendrites are thinner, more sinous and provided with a denser cover of extremely fine protoplasmatic protrusions. In corresponding pigeon neurones the dendrites are thicker, more straight and with a smaller number of rather large protoplasmatic outgrowths. Such differences apparently set up morphological prerequisites for a finer analysis and processing of information, which may contribute to greater capacity of crows for extrapolation.