Input organization of distal and proximal forelimb areas in the monkey primary motor cortex: A retrograde double labeling study
Article first published online: 9 OCT 2004
Copyright © 1993 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 333, Issue 2, pages 199–209, 8 July 1993
How to Cite
Tokuno, H. and Tanji, J. (1993), Input organization of distal and proximal forelimb areas in the monkey primary motor cortex: A retrograde double labeling study. J. Comp. Neurol., 333: 199–209. doi: 10.1002/cne.903330206
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 26 FEB 1993
- cerebral cortex;
- forelimb movements;
- motor control;
- intracortical microstimulation;
- fluorescent dyes
The present double-labeling study was designed to demonstrate the morphological framework for motor control in coordinated distal and proximal forelimb movements, which may partly, at least, depend on corticocortical and thalamocortical inputs to the forelimb area in the primary motor cortex. After intracortical microstimulation mapping of the forelimb area in the primary motor cortex of four macaque monkeys, a retrograde tracing study with fluorescent dyes was attempted to label simultaneously neurons in cortical and subcortical sites projecting to the distal forelimb representation area and those projecting to the proximal representation area of the primary motor cortex. Neurons projecting to distal and proximal forelimb parts of the primary motor cortex were largely separate in the following areas: the premotor area, primary somatosensory area, secondary somatosensory area, area 5, and thalamus. In contrast, there was no precise topographic organization of labeled projection neurons in the following areas: the supplementary motor area, cingulate motor area, primary motor cortex adjacent to the injection sites, claustrum, and basal nucleus of Meynert. The present study revealed that the forelimb area of the primary motor cortex receives both segregated and intermixed inputs from cortical and subcortical sources. In particular, the fact that the forelimb area of the primary motor cortex receives topographically organized inputs from the premotor area and nontopographically organized inputs from the supplementary motor area and cingulate motor area indicates possible different functional roles of frontal premotor areas in control of coordinated distal and proximal forelimb movements. © 1993 Wiley-Liss, Inc.