Neurosurgery notes/Anatomy/White matter tracts/Association fibres/Uncinate fasciculus

Uncinate fasciculus

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Parent item
Association fibres

General

  • A frontotemporal long association fibre pathway
  • Thick, hook/U-shaped
  • Like a continuation of the inferior longitudinal fasciculus
  • Forms the anterior part of the frontotemporal transition (also known as the temporal stem)

Parts

  • Dorsolateral part
    • Which goes to the orbitofrontal area
  • Ventromedial part
    • Which goes to the septal area from the temporal pole

Interconnections

  • Fronto-orbital region → temporomesial region (temporal pole)
  • Cortical nuclei of amygdala → subcallosal region
  • Forms part of the ventral portion of the extreme and external capsule

Relationships

  • Superficial
    • Cortical surface of limen insulae
  • Deep
    • Ventral claustrum
  • Medial and inferiorly
    • IFOF

Function

  • Behavioural inhibition
  • Emotional related memory
  • Semantic processing: Proper names
 
flowchart TD
    A["Lateral Orbitofrontal Cortex<br>• Value assignment<br>• Value updating"]
    B["BA 10"]
    C["Uncinate Fasciculus<br> Allows temporal lobe-based stimulus association (eg name + face + voice + feelings about a person) to modify behaviour via interactions with the OFC. This interaction is instrumental in assigning value (rewards/punishments) to store representations. the bidirectionality of UF information flow ensures that stored representation reflect uptodate reward & punishment history"]
    D["Temporal Pole / Ventral Anterior Temporal Cortex / Perirhinal Cortex / Amygdala <br> creates and stores mnemonic associations between objects, people & emotions"]
    E[Amygdala<br>• Adds emotional tone<br>• Personal significance<br>• Reflects recent history]

    C --> A
    C --> B
    C --> D
    C --> E
    
    D <-- Amydala-temporal fascicle --> E
		A --> E

Deficits

  • Emotional lability
  • Disinhibition
  • Semantic dementia
  • Impaired naming
  • DTI studies in patients with schizophrenia have found morphometric changes in the UF
  • Disruption of the UF during the anteromedial temporal lobectomy may be associated with psychosocial clinical improvement because the UF can no longer convey the pathological information from the temporal lobe to the orbitofrontal cortex, which is involved in decision making

Images

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AC: anterior commissure OR: optic radiation UF: uncinate fasciculus AIS, SIS, PLS, ILS: anterior, superior, posterior, inferior limiting sulcus
AC: anterior commissure
OR: optic radiation
UF: uncinate fasciculus
AIS, SIS, PLS, ILS: anterior, superior, posterior, inferior limiting sulcus
notion image
notion image