Cytoarchitecture and cortical connections of the anterior insula and adjacent frontal motor fields in the rhesus monkey.
The cytoarchitecture and cortical connections of the ventral motor region are investigated using Nissl, and NeuN staining methods and the fluorescent retrograde tract tracing technique in the rhesus monkey. On the basis of gradual laminar differentiation, it is shown that the ventral motor region stems from the ventral proisocortical area (anterior insula and dorsal Sylvian opercular region). The cytoarchitecture of the ventral motor region is shown to progress in three lines, as we have recently shown for the dorsal motor region. Namely, root (anterior insular and dorsal Sylvian opercular area ProM), belt (ventral premotor cortex) and core (precentral motor cortex) lines. This stepwise architectonic organization is supported by the overall patterns of corticocortical connections. Areas in each line are sequentially interconnected (intralineal connections) and all lines are interconnected (interlinear connections). Moreover, root areas, as well as some of the belt areas of the ventral and dorsal trend are interconnected. The ventral motor region is also connected with the ventral somatosensory areas in a topographic manner. The root and belt areas of ventral motor region are connected with paralimbic, multimodal and prefrontal (outer belt) areas. In contrast, the core area has a comparatively more restricted pattern of corticocortical connections. This architectonic and connectional organization is consistent in part, with the functional organization of the ventral motor region as reported in behavioral and neuroimaging studies which include the mediation of facial expression and emotion, communication, phonic articulation, and language in human.
University of South Dakota School of Medicine, Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, Vermillion, SD 57069, USA. Electronic address: Robert.Morecraft@usd.edu.
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Morecraft
University of South Dakota School of Medicine, Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, Vermillion, SD 57069, USA.
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Stilwell-Morecraft
University of South Dakota School of Medicine, Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, Vermillion, SD 57069, USA.
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Research Service, Bedford VA Medical Center, Bedford, MA 01730, USA; Boston University School of Medicine, Department of Anatomy and Neurobiology and Department of Neurology, Boston, MA 02118, USA.
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Cipolloni
Research Service, Bedford VA Medical Center, Bedford, MA 01730, USA; Boston University School of Medicine, Department of Anatomy and Neurobiology and Department of Neurology, Boston, MA 02118, USA; Harvard Neurological Unit, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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D000818:Animals; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D008253:Macaca mulatta / Q000033:anatomy & histology* / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques; D010784:Photomicrography
Cerebral cortex; Frontal lobe; Limbic system; Motivation; Motor behavior; Orofacial movement