Quantitative analyses of thalamic and cortical origins of neurons projecting to the rostral and caudal forelimb motor areas in the cerebral cortex of rats. 1998

Y Wang, and K Kurata
Department of Physiology, Tohoku University School of Medicine, Sendai, 980-77, Japan.

On the basis of studies using intracortical microstimulation, the existence of rostrocaudally separate two forelimb representation areas has been inferred in the motor cortex of rats. They are termed caudal and rostral forelimb areas (CFA and RFA). In this study, it was confirmed first that RFA and CFA are located in cytoarchitectonically distinct areas (medial and lateral parts of agranular cortex, respectively). In the second part of this study, the distribution of thalamic and cortical neurons projecting to RFA and CFA was quantitatively compared by injections of small and relatively constant amounts of retrograde fluorescent dyes (diamidino yellow and fast blue) into these areas. It was observed that (1) main inputs to RFA originated from AGl, namely CFA (2) CFA received dominant inputs from AGm including RFA and caudally adjacent granular cortex and (3) wider cortical areas and larger number of neurons projected to CFA than to RFA. As for the thalamocortical projections, both RFA and CFA received inputs from various thalamic nuclei, such as VL, VM, Po, PC, PF, CL, but cells projecting to RFA and CFA were differentially located in each nucleus. It was found that labeled cell number and/or density in VM, PC, CL, CM and MD after RFA injections were significantly larger than those after CFA injections. On the other hand, labeled cell number and/or density in VPL and VL were significantly higher after CFA injections than after RFA injections. In comparison with findings in primates, the results suggest that the cortical motor areas of rats may be specialized for different aspects of motor control.

UI MeSH Term Description Entries
D009044 Motor Cortex Area of the FRONTAL LOBE concerned with primary motor control located in the dorsal PRECENTRAL GYRUS immediately anterior to the central sulcus. It is comprised of three areas: the primary motor cortex located on the anterior paracentral lobule on the medial surface of the brain; the premotor cortex located anterior to the primary motor cortex; and the supplementary motor area located on the midline surface of the hemisphere anterior to the primary motor cortex. Brodmann Area 4,Brodmann Area 6,Brodmann's Area 4,Brodmann's Area 6,Premotor Cortex and Supplementary Motor Cortex,Premotor and Supplementary Motor Cortices,Anterior Central Gyrus,Gyrus Precentralis,Motor Area,Motor Strip,Precentral Gyrus,Precentral Motor Area,Precentral Motor Cortex,Premotor Area,Premotor Cortex,Primary Motor Area,Primary Motor Cortex,Secondary Motor Areas,Secondary Motor Cortex,Somatic Motor Areas,Somatomotor Areas,Supplementary Motor Area,Area 4, Brodmann,Area 4, Brodmann's,Area 6, Brodmann,Area 6, Brodmann's,Area, Motor,Area, Precentral Motor,Area, Premotor,Area, Primary Motor,Area, Secondary Motor,Area, Somatic Motor,Area, Somatomotor,Area, Supplementary Motor,Brodmann's Area 6s,Brodmanns Area 4,Brodmanns Area 6,Central Gyrus, Anterior,Cortex, Motor,Cortex, Precentral Motor,Cortex, Premotor,Cortex, Primary Motor,Cortex, Secondary Motor,Cortices, Secondary Motor,Gyrus, Anterior Central,Gyrus, Precentral,Motor Area, Precentral,Motor Area, Primary,Motor Area, Secondary,Motor Area, Somatic,Motor Areas,Motor Cortex, Precentral,Motor Cortex, Primary,Motor Cortex, Secondary,Motor Strips,Precentral Motor Areas,Precentral Motor Cortices,Premotor Areas,Primary Motor Areas,Primary Motor Cortices,Secondary Motor Area,Secondary Motor Cortices,Somatic Motor Area,Somatomotor Area,Supplementary Motor Areas
D009434 Neural Pathways Neural tracts connecting one part of the nervous system with another. Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D001931 Brain Mapping Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures. Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D005552 Forelimb A front limb of a quadruped. (The Random House College Dictionary, 1980) Forelimbs
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013788 Thalamus Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain. Thalamencephalon,Thalamencephalons
D017207 Rats, Sprague-Dawley A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company. Holtzman Rat,Rats, Holtzman,Sprague-Dawley Rat,Rats, Sprague Dawley,Holtzman Rats,Rat, Holtzman,Rat, Sprague-Dawley,Sprague Dawley Rat,Sprague Dawley Rats,Sprague-Dawley Rats
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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