Anatomy and white matter connections of the orbitofrontal gyrus

Abstract

OBJECTIVE The orbitofrontal cortex (OFC) is understood to have a role in outcome evaluation and risk assessment and is commonly involved with infiltrative tumors. A detailed understanding of the exact location and nature of associated white matter tracts could significantly improve postoperative morbidity related to declining capacity. Through diffusion tensor imaging-based fiber tracking validated by gross anatomical dissection as ground truth, the authors have characterized these connections based on relationships to other well-known structures. METHODS Diffusion imaging from the Human Connectome Project for 10 healthy adult controls was used for tractography analysis. The OFC was evaluated as a whole based on connectivity with other regions. All OFC tracts were mapped in both hemispheres, and a lateralization index was calculated with resultant tract volumes. Ten postmortem dissections were then performed using a modified Klingler technique to demonstrate the location of major tracts. RESULTS The authors identified 3 major connections of the OFC: a bundle to the thalamus and anterior cingulate gyrus, passing inferior to the caudate and medial to the vertical fibers of the thalamic projections; a bundle to the brainstem, traveling lateral to the caudate and medial to the internal capsule; and radiations to the parietal and occipital lobes traveling with the inferior fronto-occipital fasciculus. CONCLUSIONS The OFC is an important center for processing visual, spatial, and emotional information. Subtle differences in executive functioning following surgery for frontal lobe tumors may be better understood in the context of the fiber-bundle anatomy highlighted by this study.

Pain and reward circuits antagonistically modulate alcohol expectancy to regulate drinking

“…During alcohol cue exposure, we again observed the opposing effects of the PAG and mOFC but with the involvement of the OC. While the recruitment of the visual cortex may not be surprising given its robust activation to alcohol cues 10 and anatomical connections with both mOFC 68 and PAG 69 , the current findings suggest a more direct role of the OC in shaping drinking behavior. Previous theoretical work proposes that the visual cortex links perceptual processing of drug cues to the psychophysiological responses to actual consumption 70 .…”

Brain Imaging Study on the Pathogenesis of Depression & Therapeutic Effect of Selective Serotonin Reuptake Inhibitors

“…The orbitofrontal cortex (OFC) is a subregion of the prefrontal cortex, inferiorly to the superior frontal gyrus (SFG) and the medial frontal gyrus (MFG), and partially at the middle-lower pars triangularis (PT). 23 OFC controls emotions and affections, mainly collecting the signals transmitted from sensory areas and is highly connected with the limbic brain regions such as the amygdala, which plays a vital role in emotional assessment. This study showed that reductions of gray matter volume observed in the orbital part of the right medial frontal gyrus and right inferior frontal gyrus was the brain structure background for mood and cognitive impairment in MDD patients.…”

Anatomy and white matter connections of the inferior frontal gyrus

“…To validate tractography results we sought to demonstrate the location of white matter tracts connecting to the IFG with gross anatomical dissections as ground truth (Catani et al ; Burks et al ; Burks et al ; Burks et al ). Postmortem dissections were performed using a modified Klingler technique (Koutsarnakis et al ).…”