The first detailed 'Anatomy of the Brain' was by Thomas Willis. It was published in 1664.
Willis had a different view of the brain than did Descartes. He felt that the structures of the brain itself had influence on behavior, rather than the cerebral spinal fluid or the ventricles.
Thomas also found that there were two types of tissue in the brain; gray matter and white matter.
Willis did however agree with Descartes about the matter of the spirits. He felt that the white matter was a series of channels used to distribute the spirits that were generated in the gray matter.