QUANTITATIVE MORPHOLOGICAL ANALYSIS OF THE HUMAN INSULAR CORTEX: A CADAVERIC STUDY
Main Article Content
Keywords
Morphology, Morphometric, Insular cortex, Gyri, Sulci, Anatomical Variation.
Abstract
Introduction and Aim: The insular cortex, a concealed fifth lobe of the brain, exhibits significant variability in its gross anatomical organization within the operculoinsular compartment of the Sylvian fissure. This study aimed to comprehensively characterize the morphological patterns and morphometric features of the insular gyri and sulci in a cohort of human cadaveric cerebral hemispheres.
Materials and Methods: Fifty-eight formalin-fixed human cerebral hemispheres were meticulously examined to identify variations in the gyri and sulci of the insular cortex. The lengths of these structures were precisely measured using a digital vernier caliper. This investigation was conducted in the Department of Anatomy at Gandhi Medical College, Bhopal.
Results: Morphological analysis revealed both typical and variant insular patterns, including discontinuous sulci and fused gyri. Among the observed variations (21%, 85/406 gyri), bifid gyri were most frequent (10.3%, 44/406), particularly affecting the anterior short gyrus (41%, 18/44). Hypoplastic gyri constituted 7.63% (31/406) of variations and were most commonly found in the middle short gyri (58%, 18/31). Trifid gyri were observed in 2.46% (10/406) of cases. Notably, transverse gyri were present in 22.41% (13/58) and accessory gyri in 65.51% (39/58) of hemispheres, while both were absent in 32.76% (19/58). The mean lengths of the insular gyri were: anterior short (24.54mm), middle short (25.04mm), posterior short (34.08mm), anterior long (36.87mm), and posterior long (37.1mm). The mean lengths of the insular sulci were: central insular (35.3mm), superior periinsular (52.48mm), anterior periinsular (24.5mm), inferior periinsular (26.4mm), and posterior periinsular (12.81mm).
Conclusion: This study highlights the considerable morphological variability of the insular gyri, with bifid, trifid, and hypoplastic patterns being prevalent. The presence of transverse and accessory gyri, primarily in the anterior insula, contributes to variations in the total number of gyri, making the anterior lobule generally larger but with shorter gyri compared to the posterior lobule. These detailed morphological and morphometric findings of the insular cortex are crucial for neurosurgical planning and understanding individual anatomical differences.
References
2. Augustine, J. R. (1996). Circuitry and functional aspects of the insular lobe in primates including humans. Brain Research Reviews, 22(3), 229-244..
3. Mesulam, M. M., & Mufson, E. J. (1982a). Insula of the old-world monkey. I. Cytoarchitecture and chemoarchitecture. Journal of Comparative Neurology, 212(1), 1-22.
4. Mesulam, M. M., & Mufson, E. J. (1982b). Insula of the old-world monkey. II. Afferent cortical input and comments on the claustrum. Journal of Comparative Neurology, 212(1), 23-41
5. Mesulam, M. M., & Mufson, E. J. (1982c). Insula of the old-world monkey. III. Efferent cortical output and comments on function. Journal of Comparative Neurology, 212(1), 42-66.
6. Nieuwenhuys, R. (2012). The human central nervous system. Springer Science & Business Media.
7. Morel, A., Gallay, M. N., Jeanmonod, D., Seeck, M., & Vercueil, L. (2013). Cytoarchitectonic organization of the human insula and adjacent cortex. Brain Structure and Function, 218(5), 1231-1249.
8. von Economo, C., & Koskinas, G. N. (1925). Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen. Springer.
9. Braak, H. (1980). Architectonics of the human telencephalic cortex. Studies of Brain Function, 4, 1-183.
10. Bonthius, D. J., Solodkin, A., & Van Hoesen, G. W. (2005). Pathology of the insular cortex in Alzheimer disease depends on cortical architecture. Journal of Neuropathology & Experimental Neurology, 64(10), 910-922.
11. Türe, U., Yaşargil, M. G., Al-Mefty, O., & Yasargil, D. C. (1999). Topographic anatomy of the insular region. Journal of Neurosurgery, 90(4), 720-733.
12. Cortex in Human Cadaveric Brains. Indian Journal of Clinical Anatomy and Physiology, 5(2), 194-197.
13. Britton, J. C., Phan, K. L., Taylor, S. F., Welsh, R. C., Berridge, K. C., & Liberzon, I. (2006). Neural correlates of social anxiety during public speaking. Social Cognitive and Affective Neuroscience, 1(1), 38-46.
14. Craig, A. D. B. (2002). How do you feel? Interoception: the sense of the physiological condition of the body. Nature Reviews Neuroscience, 3(8), 655-666.
15. Damasio, A. R., Grabowski, T. J., Bechara, A., Tranel, D., Ponto, L. L. B., Hichwa, R. D., & Damasio, H. (2000). Subcortical and cortical brain activity during the feeling of self-generated emotions. Nature Neuroscience, 3(10), 1049-1056.
16. Naqvi, N. H., & Bechara, A. (2010). The hidden island: the insula and drug addiction. Brain Research, 1350, 130-149
Article Sidebar
Article Details
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
All articles published in JPTCP are licensed under Copyright Creative Commons Attribution-NonCommercial 4.0 International License.
Dr Jaya Deshmukh
Demonstrator, Department of Anatomy, Gandhi Medical College Hamidia Hospital, Bhopal.
Dr Deepak Sharma
Assistant Professor, Department of Anatomy, Gandhi Medical College Hamidia Hospital, Bhopal.
Dr Vandana Sharma
Professor and Head, Department of Anatomy, Gandhi Medical College Hamidia Hospital, Bhopal.
Dr Juhi Agarwal
Assistant Professor, Department of Physiology, Gandhi Medical College Hamidia Hospital, Bhopal.