Frontal terminations for the inferior fronto-occipital fascicle: anatomical dissection, DTI study and functional considerations on a multi-component bundle.
The anatomy and functional role of the inferior fronto-occipital fascicle (IFOF) remain poorly known. We accurately analyze its course and the anatomical distribution of its frontal terminations. We propose a classification of the IFOF in different subcomponents. Ten hemispheres (5 left, 5 right) were dissected with Klingler's technique. In addition to the IFOF dissection, we performed a 4-T diffusion tensor imaging study on a single healthy subject. We identified two layers of IFOF. The first one is superficial and antero-superiorly directed, terminating in the inferior frontal gyrus. The second is deeper and consists of three portions: posterior, middle and anterior. The posterior component terminates in the middle frontal gyrus (MFG) and dorso-lateral prefrontal cortex. The middle component terminates in the MFG and lateral orbito-frontal cortex. The anterior one is directed to the orbito-frontal cortex and frontal pole. In vivo tractography study confirmed these anatomical findings. We suggest that the distribution of IFOF fibers within the frontal lobe corresponds to a fine functional segmentation. IFOF can be considered as a "multi-function" bundle, with each anatomical subcomponent subserving different brain processing. The superficial layer and the posterior component of the deep layer, which connects the occipital extrastriate, temporo-basal and inferior frontal cortices, might subserve semantic processing. The middle component of the deep layer could play a role in a multimodal sensory-motor integration. Finally, the anterior component of the deep layer might be involved in emotional and behavioral aspects.
Division of Neurosurgery, Department of Neurosciences and Rehabilitation, S. Anna University-Hospital, 203 C.so della Giovecca, 44100 Ferrara, Italy.
Silvio
S
Sarubbo
Alessandro
A
De Benedictis
Igor L
IL
Maldonado
Gianpaolo
G
Basso
Hugues
H
Duffau
D001519:Behavior; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology; D056324:Diffusion Tensor Imaging; D004210:Dissection; D004644:Emotions; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D008959:Models, Neurological; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D009778:Occipital Lobe / Q000033:anatomy & histology / Q000502:physiology; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000502:physiology