Superior longitudinal fasciculus

View Details

Status

Done

Shape

Reversed C-shaped structure surrounding the insula

Interconnection

Lateral frontoparietotemporal connections

Interconnects the frontal and temporal lobes

Connects

Broca area
Wernicke area
Geschwind area

notion image

Relations

Superficial to

The corona radiata and external capsule

Deep to

Function

Non dominant

Spatial awareness

Dominant

Language (repetition)

Segments

notion image

Arcuate fibre

Frontoparietal segments

Aka

Horizontal segment
Anterior segment

3 parts

$\color{#35b5a0}{SLF I (dorsal pathway)}$

Courses within the superior bank of the cingulate sulcus

Just above the cingulum

Pathway

Dorsal superior parietal lobe and the medial parietal lobe (precuneus) → through the white matter of the superior parietal and frontal regions → premotor and prefrontal cortex (dorsal parts of areas 6, 8, and 9 and the supplementary motor area)

notion image — $\color{#35b5a0}{SLF I (dorsal pathway)}$

$\color{#ba6da9}{SLF II (middle pathway)}$

Extends from the inferior parietal lobe to the middle frontal gyrus

Within Middle frontal gyrus

Pathway

Posterior portion of the inferior parietal lobe (angular gyrus) → through the central core of the white matter above the superior limiting sulcus of the insula → dorsal premotor and prefrontal regions.

Medial: Corona radiata

notion image — $\color{#ba6da9}{SLF II (middle pathway)}$

$\color{bfc978}{SLF III (ventral pathway)}$

Within the frontoparietal operculum

Pathway

Anterior portion of the inferior parietal lobe (supramarginal gyrus) → through the opercular white matter of the parietal and frontal lobes → ventral premotor and prefrontal cortex (Broca’ s territory)

notion image — $\color{bfc978}{SLF III (ventral pathway)}$

Function a high order multisensory associative system → deficits

Rt hemisphere: Visual spatial processing → Left spatial hemineglect
Lt hemisphere: Dorsal phonological pathway (motor language) → Phonological apraxia

Temporoparietal segment

Aka

Vertical segment
Posterior segment

Craniocaudally orientated

Runs parallel and lateral to arcuate fasciculus

Pathway

Posterior part of the superior and middle temporal gyrus (wernicke's area) → Inferior parietal lobe

Function → deficits

Audiospatial processing → vestibular symptoms
Sensitive language (auditory comprehension) → sensitive aphasia

Frontotemporal segment

Aka

Arcuate segment
Arcuate fasciculus
Long segment

Two parts

$\color{#d08966}{Dorsal}$
$\color{#7273a7}{Ventral}$

Originates

Wernicke's area (posterior parts of the superior, middle and inferior temporal gyri)

Arches around the caudal end of the Sylvian fissure, running within the white matter of the parietal and frontal operculi

Runs

Parallel and medial to the two other SLF tracts
Lateral to the corticospinal tract

Terminates (controversial)

Precentral gyrus
Broca's areas (Posterior two-thirds of the inferior frontal gyrus) composed of

Pars opercularis
Pars triangularis

Function → deficits

Visu-audio spatial → Vestibular symptoms (?)
Repetition → conductive aphasia

Precentral gyrus

Pars opercularis

Arcuate fibres

Pars triangularis

Clinical

Segment of SLF	Functional Role	Disconnection Syndrome
Frontoparietal segment	Visuospatial processing	Left spatial hemineglect
ㅤ	Dorsal phonological pathway (motor language)	Phonological apraxia
Temporoparietal segment	Audiospatial processing	Vestibular symptoms
ㅤ	Sensitive language (auditory comprehension)	Sensitive aphasia
Frontotemporal or arcuate segment	Visu-audiospatial (?)	Vestibular symptoms (?)
ㅤ	Repetition	Conductive aphasia

Images

A, removal of the cortical gray matter and adjacent superficial short fibers of the frontal, temporal, and parietal opercula, the middle frontal, superior temporal, and middle temporal gyri, and the inferior parietal lobule exposes the superior longitudinal fasciculus arching around the outer edges of the insula. The superior parietal lobule and the pars orbicularis of the inferior frontal gyrus are intact. Long fibers are observed descending from the frontal opercula, precentral and postcentral gyri, inferior parietal lobule, and transverse superior and middle temporal gyri.

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