Organization of frontoparietal cortex in the tree shrew (Tupaia belangeri). I. Architecture, microelectrode maps, and corticospinal connections
- 5 May 2006
- journal article
- research article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 497 (1), 133-154
- https://doi.org/10.1002/cne.20975
Abstract
Despite extensive investigation of the motor cortex of primates, little is known about the organization of motor cortex in tree shrews, one of their closest living relatives. We investigated the organization of frontoparietal cortex in Belanger's tree shrews (Tupaia belangeri) by using intracortical microstimulation (ICMS), corticospinal tracing, and detailed histological analysis. The results provide evidence for the subdivision of tree shrew frontoparietal cortex into seven distinct areas (five are newly identified), including two motor fields (M1 and M2) and five somatosensory fields (3a, 3b, S2, PV, and SC). The types of movements evoked in M1 and M2 were similar, but M2 required higher currents to elicit movements and had few connections to the cervical spinal cord and distinctive cyto‐ and immunoarchitecture. The borders between M1 and the anterior somatosensory regions (3a and 3b) were identified primarily from histological analysis, because thresholds were similar between these regions, and differences in corticospinal neuron distribution were subtle. The caudal (SC) and lateral (S2 and PV) somatosensory fields were identified based on differences in architecture and distribution of corticospinal neurons. Myelin‐dense modules were identified in lateral cortex, in the expected location of the oral, forelimb, and hindlimb representations of S2, and possibly PV. Evidence for a complex primate‐like array of motor fields is lacking in tree shrews, but their motor cortex shares a number of basic features with that of primates, which are not found in more distantly related species, such as rats. J. Comp. Neurol. 497:133–154, 2006.Keywords
This publication has 91 references indexed in Scilit:
- Spatial coding of position and orientation in primary visual cortexNature Neuroscience, 2002
- Descending pathways to the spinal cord, III: Sites of origin of the corticospinal tractJournal of Comparative Neurology, 1990
- Frontal eye field as defined by intracortical microstimulation in squirrel monkeys, owl monkeys, and macaque monkeys II. cortical connectionsJournal of Comparative Neurology, 1987
- The motor cortex of the rat: Cytoarchitecture and microstimulation mappingJournal of Comparative Neurology, 1982
- Physiological and anatomical evidence for a discontinuous representation of the trunk in S-I of tree shrewsJournal of Comparative Neurology, 1981
- Representation of the body surface in somatosensory area I of tree shrews,Tupaia glisJournal of Comparative Neurology, 1980
- Frontal ‘oculomotor’ area in alert cat. I. Eye movements and neck activity evoked by stimulationBrain Research, 1978
- Superior Colliculus of the Tree Shrew: A Structural and Functional Subdivision into Superficial and Deep LayersScience, 1972
- EARLY FORERUNNERS OF MANThe American Journal of the Medical Sciences, 1934