science

Superior longitudinal fasciculus

Superior longitudinal fasciculus is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Superior longitudinal fasciculus rather than just read about it. In short: The superior longitudinal fasciculus (SLF) is an association tract in the brain that is composed of three separate components. It is present in both hemispheres and can be found lateral to the centrum semiovale and connects the frontal, occipital, parietal, and temporal lobes.

Key takeaways

Superior longitudinal fasciculus belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Superior longitudinal fasciculus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Superior longitudinal fasciculus from memory before moving on to harder problems.

Reference excerpt

The superior longitudinal fasciculus (SLF) is an association tract in the brain that is composed of three separate components. It is present in both hemispheres and can be found lateral to the centrum semiovale and connects the frontal, occipital, parietal, and temporal lobes. This bundle of tracts (fasciculus) passes from the frontal lobe through the operculum to the posterior end of the lateral sulcus where they either radiate to and synapse on neurons in the occipital lobe, or turn downward and forward around the putamen and then radiate to and synapse on neurons in anterior portions of the temporal lobe. The SLF is composed of three distinct components SLF I, SLF II, and SLF III.

SLF I SLF I is the dorsal component and originates in the superior and medial parietal cortex, passes around the cingulate sulcus and in the superior parietal and frontal white matter, and terminates in the dorsal and medial cortex of the frontal lobe (Brodmann 6, 8, and 9) and in the supplementary motor cortex (M II). SLF I connects to the superior parietal cortex which encodes locations of body parts in a body-centric coordinate system and with M II and dorsal premotor cortex. This suggests the SLF I is involved with regulating motor behavior, especially conditional associative tasks which select among competing motor tasks based on conditional rules.

SLF II SLF II is the major component of SLF and originates in the caudal-inferior parietal cortex and terminates in the dorsolateral prefrontal cortex (Brodmann 6, 8 and 46). SLF II connects to the caudal inferior parietal cortex which controls spatial attention and visual and oculomotor functions. This suggests the SLF II provides the prefrontal cortex with parietal cortex information regarding perception of visual space. Since these bundles are bi-directional, working memory (Brodmann 46) in the prefrontal cortex may provide the parietal cortex with information to focus spatial attention and regulate selection and retrieval of spatial information. Some research suggests a larger SLF II volumes in the "right hemisphere corresponded to faster detection times in the left hemifield". An hemispheric specialization that "is associated with an unbalanced speed of visuospatial processing along the SLF II. This lateralization may be predictive of visuospatial recovery in patients with lesions of parietofrontal networks."

SLF III SLF III is the ventral component and originates in the supramarginal gyrus (rostral portion of the inferior parietal lobe) and terminates in the ventral premotor and prefrontal cortex (Brodmann 6, 44, and 46). SLF III connects the rostral inferior parietal cortex which receives information from the ventral precentral gyrus. This suggests that the SLF III transfers somatosensory information, such as language articulation, between the ventral premotor cortex, Brodmann 44 (pars opercularis), the supramarginal gyrus (Brodmann 40), and the laterial inferior prefrontal cortex working memory (Brodmann 46).

References

External links

Atlas image: n1a5p6 at the University of Michigan Health System - "Dissection of the Left Hemisphere"

Illustrations

Worked examples

Example 1 — a first encounter with Superior longitudinal fasciculus

Start with the simplest possible case. Write down what Superior longitudinal fasciculus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Superior longitudinal fasciculus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Superior longitudinal fasciculus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Superior longitudinal fasciculus

In research: Superior longitudinal fasciculus appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Superior longitudinal fasciculus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Superior longitudinal fasciculus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Central nervous system pathways, Cerebral white matter, so understanding it makes those chapters shorter.
In everyday life: Look for Superior longitudinal fasciculus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Superior longitudinal fasciculus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Superior longitudinal fasciculus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Superior longitudinal fasciculus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Superior longitudinal fasciculus in simple terms?

Why does Superior longitudinal fasciculus matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Superior longitudinal fasciculus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Superior longitudinal fasciculus.