Libelle of note

Although in the Fasciculus arcuatus (Arcuate fasciculus) three segments (anterior, long and posterior) were distinguished (Cayani M, Jones DK, ffytche DH 2005 Perisylvian language pathways. Ann Neurol 57:8-16), more recent research showed that the anterior segment belongs to the superior longitudinal fasciculus and the posterior segment is in reality separate and was renamed Fasciculus temporoparietalis verticalis (temporoparietal vertical or aslant tract), leaving the long segment as the true arcuate fasciculus (Fernandez-Miranda JC, Wang Y, Pathak S, et al. 2015 Asymmetry, connectivity, and segmentation of the arcuate fascicle in the human brain. Brain Struct Funct 220:3665-3680)

The Fasciculus longitudinalis superior (Superior longitudinal fasciculus) appears to be composed of three bundles (SLFI-III or Superior, Middle and Inferior; Makris N, Kennedy DN, McInerney S, et al. 2005 Segmentation of subcomponents within the superior longitudinal fascicle in humans: A quantitative, in vivo, DT-MRI study. Cereb Cortex 15:854-869) as in monkeys (Schmahmann JD, Pandya DN 2006 Fiber Pathways of the Brain. Oxford University Press, New York; Thiebaut de Schotten M, Dell'Acqua F, Valabreque R, Catani M 2012 Monkey to human comparative anatomy of the frontal lobe association tracts. Cortex 48:82-96).

Here, the new nomenclature for the long association fibres of the cerebrum is advocated as proposed by Mandonnet E, Sarubbo S, Petit L (2018 The nomenclature of human white matter association pathways: Proposal for a systematic taxonomic anatomical classification. Front Neuroanat 12:94).

The Fibrae U-figuratae (U-shaped fibres) were first described by Meynert (1872), and replaced the term Fibrae arcuatae cerebri (Arnold 1838) that became obsolete.

Recently, the Fasciculus temporoparietalis verticalis (Temporoparietal aslant tract) was demonstrated, replacing the vertical segment of the arcuate fasciculus (Panesar SS, Belo JT, Yeh F-C, Fernandez-Miranda JC 2019 Structure, asymmetry, and connectivity of the human temporo-parietal asland and vertical occipital fasciculi. Brain Struct Funct 224:907-923; see also 6273).

The Fasciculus subcallosus (Subcallosal fasciculus or Bundle of Muratoff; Muratoff W 1893 Secundäre Degenerationen nach Durchschneidung des Balkens. Neurol Centralbl 12:714-729) forms a separate bundle of Corticostriatal fibres (see Schmahmann JD, Pandya DN 2007 The complex history of the fronto-occipital fasciculus. J Hist Med 16:362-377).

The Fasciculus frontalis obliquus (Frontal aslant tract or Frontal oblique tract) connects the SMA and pre-SMA with the opercular part of the Inferior frontal gyrus (Catani M, Dell'Acqua F, Vergani F, et al. 2012 Short frontal lobe connections of the human brain. Cortex 48:273-291).