The sulcal patterns of the human orbitofrontal cortex have not been adequately characterized. Classical authors, as well as more recent investigators, have attempted to identify and label the sulci of this part of the brain. Nevertheless, there is considerable confusion regarding the orbital sulcal patterns with inconsistencies in the naming of orbitofrontal sulci in many modern texts. Moreover, a correlation between specific landmarks and architectonic areas has not been demonstrated. / A clarification of the patterns of the orbitofrontal sulci and their relationship to architectonic subregions is necessary if the results of functional neuroimaging and other physiological and anatomical findings are to be properly interpreted. Although studies have reported altered activity in the orbitofrontal cortex in relation to various sensory processes and pathological states it has been difficult to relate these changes to specific orbitofrontal regions because of a limited understanding of the anatomical landmarks. The absence of reliable reference markers forces the use of vague terminology (e.g., "orbital frontal activation") in describing the location of functional changes in the orbital frontal cortex. / The aim of this doctoral thesis was to gain a better understanding of the sulcal pattern of the human orbitofrontal cortex and its relation to the underlying cytoarchitecture. The first study resolved the confusion associated with the orbitofrontal sulci by identifying, quantifying, and precisely localizing the various orbital sulci from fifty human magnetic resonance scans that were transformed into the standardized stereotaxic space of Talairach and Tournoux (1988). The second study compared the individual sulci and sulcal patterns of these fifty human brains with the brains of fifty adult rhesus monkeys. Having examined the orbitofrontal sulci in these two species, a nomenclature for the human orbitofrontal sulci was established which was based on comparable sulci in the less convoluted macaque monkey brain while trying to preserve many of the familiar labels associated with this region in the human brain. The final part of this thesis examined the orbitofrontal cytoarchitecture of 10 human adult cerebral hemispheres to determine if a correlation exists between the different orbital sulci and the borders of the architectonic subregions.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37646 |
| Date | January 2001 |
| Creators | Chiavaras, Mary M. |
| Contributors | Petrides, Michael (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Division of Neuroscience.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001862344, proquestno: NQ78664, Theses scanned by UMI/ProQuest. |
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