Though many experimental and clinical studies1 have recently been made on the premotor area (area 6), little is known concerning its anatomic connections. Kennard2 has shown that lesions restricted to that region of the cortex of the monkey give rise to spinal degenerations demonstrable by the Marchi method. Since premotor corticospinal fibers descend through the brain and brain stem along with the pyramidal fibers, it becomes a problem of importance to know where and how these fibers end in the spinal cord. The bouton method, previously used for studying terminations of the pyramidal tracts3 and posterior root fibers,4 has been utilized, since it allows an estimation of the proportion of ipsilateral to contralateral fibers, as well as a determination of the individual neurons on which each fiber terminates.
The bouton method is based on the observation that severing axons from their cell bodies results in
E. C. HOFF. CORTICOSPINAL FIBERS ARISING IN THE PREMOTOR AREA OF THE MONKEYDISTRIBUTION OF BOUTON TERMINATIONS. Arch NeurPsych. 1935;33(4):687–697. doi:10.1001/archneurpsyc.1935.02250160002001