Short frontal lobe connections of the human brain

Marco Catani, Flavio Dell’Acqua, Francesco Vergani, Farah Malik, Harry Hodge, Prasun Roy, Romain Valabregue, Michel Thiebaut de Schotten
Cortex. 2012-02-01; 48(2): 273-291
DOI: 10.1016/j.cortex.2011.12.001

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1. Cortex. 2012 Feb;48(2):273-91. doi: 10.1016/j.cortex.2011.12.001. Epub 2011 Dec

Short frontal lobe connections of the human brain.

Catani M(1), Dell’acqua F, Vergani F, Malik F, Hodge H, Roy P, Valabregue R,
Thiebaut de Schotten M.

Author information:
(1)Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute
of Psychiatry, King’s College London, UK.

Advances in our understanding of sensory-motor integration suggest a unique role
of the frontal lobe circuits in cognition and behaviour. Long-range afferent
connections convey higher order sensory information to the frontal cortex, which
in turn responds to internal and external stimuli with flexible and adaptive
behaviour. Long-range connections from and to frontal lobes have been described
in detail in monkeys but little is known about short intralobar frontal
connections mediating local connectivity in humans. Here we used spherical
deconvolution diffusion tractography and post-mortem dissections to visualize the
short frontal lobe connections of the human brain. We identified three intralobar
tracts connecting: i) posterior Broca’s region with supplementary motor area
(SMA) and pre-supplementary motor area (pre-SMA) (i.e., the frontal ‘aslant’
tract – FAT); ii) posterior orbitofrontal cortex with anterior polar region
(i.e., fronto-orbitopolar tract – FOP); iii) posterior pre-central cortex with
anterior prefrontal cortex (i.e., the frontal superior longitudinal – FSL
faciculus system). In addition more complex systems of short U-shaped fibres were
identified in the regions of the central, pre-central, perinsular and
fronto-marginal sulcus (FMS). The connections between Broca and medial frontal
areas (i.e. FAT) and those between the hand-knob motor region and post-central
gyrus (PoCG) were found left lateralized in a group of twelve healthy
right-handed subjects. The existence of these short frontal connections was
confirmed using post-mortem blunt dissections. The functional role of these
tracts in motor learning, verbal fluency, prospective behaviour, episodic and
working memory is discussed. Our study provides a general model for the local
connectivity of the frontal lobes that could be used as an anatomical framework
for studies on lateralization and future clinical research in neurological and
psychiatric disorders.

Copyright © 2011 Elsevier Srl. All rights reserved.

DOI: 10.1016/j.cortex.2011.12.001
PMID: 22209688 [Indexed for MEDLINE]

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