A lesion in the right anterior limb of the internal capsule most characteristically disrupts which connections?
- A Thalamocortical (anterior thalamic peduncle) fibres between the mediodorsal thalamus and prefrontal cortex, plus anterior corona radiata ✓
- B Corticospinal fibres to the left leg
- C Optic radiations (geniculocalcarine fibres)
- D Auditory radiations from the medial geniculate
Explanation
The anterior limb of the internal capsule lies between the caudate nucleus (medially) and the lentiform nucleus (laterally). It transmits the anterior thalamic peduncle — thalamocortical fibres connecting the mediodorsal and anterior thalamic nuclei with the prefrontal and cingulate cortex — and frontopontine fibres. Lesions here can produce frontal lobe disconnection, cognitive/personality changes, and executive dysfunction. The corticospinal fibres (especially to the leg) travel in the posterior limb. Optic radiations are in the retrolenticular part of the posterior limb and sublenticular capsule. Auditory radiations are in the sublenticular capsule.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.