General
- Aka: ventral extreme-external capsule
- Looks like two open fans joined at limen insulae above the uncinate fasciculus
Relations
- Anterior: Uncinate fasciculus
- Laterally
- Uncinate fasciculus
- UF crosses the anterior 1/3 of the temporal stem, passing through the region of the limen insulae and a few millimeters of the inferior limiting sulcus of the insula
- IFOF crosses the posterior 2/3 of the temporal stem, in the region between the posterior limit of the UF and the lateral geniculate body
- Inferior longitudinal fasciculus
- Superficial: Insular cortex
- Deep: temporal horn
- Forms the roof of temporal horn
- Medially
- Anterior Commissure
- IFOF separates the origin of the auditory and optic radiations at the medial and lateral geniculate bodies
- The initial segment of the auditory radiations coming from the medial geniculate body passes above the IFOF at the temporal stem,
- The initial segment of the optic radiations coming from the lateral geniculate body passes below the IFOF
- Internal capsule
- Dorsally
- Lentiform nucleus
Interconnections
- Summary: Frontotemporal → occipital
- Dorsal component
- Frontal lobe → superior parietal lobe + posterosuperior occipital lobe
- Ventral component
- Frontal lobe → posteroinferior occipital lobe + posterior basal temporal lobe
Function
- Verbal semantic processing
- Non verbal semantic processing
- Awareness inhibitory control
- Inhibitory control
Deficits
- Semantic paraphasia:
- Entire word is substituted for the intended word: son for daughter, orange instead of apple
- Anomia:
- A form of aphasia in which the patient is unable to recall the names of everyday objects.
- Abnormal pyramid and palm tree test:
- Assess semantic access from words and pictures. Determine the degree to which a subject can access meaning from pictures and words.
- Perseveration:
- Repetition of a particular response (such as a word, phrase, or gesture) regardless of the absence or cessation of a stimulus.
- Conductive aphasia
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