Dendritic bundles: survey of anatomical experiments and physiological theories.

Dendritic bundles have been found throughout the mammalian brain. Unquestionably, these bundles must serve one or more important, fundamental roles in the brain's functioning. However, no physiological experiments to determine their function have been performed on these well-established anatomical units. We survey the numerous anatomical reports of bundling. In addition, we discuss several physiological possibilities for the functional significance of bundles.