Nerve pathway · one in each half of the brain

Inferior fronto-occipital fasciculus

Also called IFOF, Inferior occipitofrontal fasciculus

One of the brain's longest cables, running from the back of your head to your forehead.

Open in 3D

The inferior fronto-occipital fasciculus, or IFOF for short, is one of the longest fiber bundles in the brain. It runs all the way from the visual areas at the back of the head to the frontal lobe behind the forehead, squeezing through a narrow passage under the insula on the way. It is thought to be a main route for linking what you see, read, and hear to its meaning.

Where it is

Deep inside each half of the brain. It starts in the occipital lobe and nearby areas, runs forward deep under the side of the temporal lobe, squeezes through a narrow bridge under the insula, and fans out into the frontal lobe.

What it does

Think of it as a long-distance express rail line from the brain's camera room at the back to its planning office at the front.

Works with

• Lateral occipital cortexIts back end starts in visual areas like this one, which recognize objects.
• Fusiform gyrusIt is thought to link this area, which recognizes faces and written words, with the frontal lobe.
• InsulaIt squeezes through a narrow passage just beneath the insula on its way forward.
• Uncinate fasciculusThe two bundles share the same narrow passage under the insula before splitting apart.
• Pars triangularisIts front end reaches this part of Broca's area, which helps choose the right words.
• Lateral orbitofrontal cortexSome fibers end here, above the eyes, in an area that weighs choices.

When it goes wrong

For learning only, not medical advice. If you have a health concern, talk to a doctor.

Surprising facts

• Its narrow passage under the insula is shared with other important bundles, so surgeons working in this area must be extremely careful.

Where the name comes from

A descriptive name: inferior means "lower", fronto-occipital means "from the front of the head to the back", and fasciculus is Latin for "little bundle". The lower front-to-back bundle.

Sources

1. External capsule, Radiopaedia
2. Extreme capsule, Radiopaedia

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