Posterior limb of internal capsule R

Overview

The bilateral Posterior limb of internal capsule R, as defined in the JHU ICBM labels 2 mm atlas, corresponds to a major white matter tract within the internal capsule that contains ascending and descending projection fibers connecting the cerebral cortex with subcortical and spinal targets. Anatomically, it lies between the thalamus medially and the lentiform nucleus laterally, with its posterior limb specifically conveying corticospinal, corticobulbar, and thalamocortical fibers crucial for voluntary motor control and somatosensory transmission. Damage to this region frequently results in contralateral motor weakness or paralysis and sensory deficits, reflecting its dense concentration of motor and sensory pathways. A closely related structure with a dedicated article is the Internal capsule.

The bilateral posterior limb of the internal capsule (PLIC), as defined in the JHU ICBM-DTI-81 2 mm atlas, has been implicated in several genetic and genome-wide association studies that link white matter microstructure and integrity to specific variants and polygenic influences. Diffusion MRI GWAS consistently identify common variants in genes affecting myelination, axon guidance, and oligodendrocyte function (e.g., variants near or within genes such as MAG, NRG1, CNTN4, and those involved in lipid metabolism) as contributors to fractional anisotropy and mean diffusivity in the internal capsule and related corticospinal tracts. Polygenic risk for schizophrenia, bipolar disorder, and major depressive disorder has been associated with altered microstructure in the PLIC, and individual risk variants in genes related to neurodevelopment (such as DISC1 and NRG1) have been linked indirectly via case–control imaging genetics to abnormalities in internal capsule integrity. GWAS of stroke and small-vessel disease, including variants near or in genes influencing vascular integrity and blood–brain barrier function (e.g., COL4A1/2, HTRA1), have connected lesion burden and ischemic damage in regions encompassing the internal capsule with specific risk alleles, reflecting the region’s vulnerability in lacunar infarcts. Moreover, imaging genetics studies in neurodegenerative disorders such as multiple sclerosis and ALS associate susceptibility alleles in immune and neuroinflammatory genes (e.g., HLA loci, IL2RA, and others) with demyelination and tract degeneration affecting the PLIC. Collectively, these findings indicate that genetic influences on myelin, vascular health, and neurodevelopment converge on the microstructural properties and disease vulnerability of the posterior limb of the internal capsule.

Overview generated by GPT-4o (2026).

Region ID: 19
Hemisphere: bilateral
Atlas: JHU ICBM labels 2mm

Posterior limb of internal capsule R – Black Background (Full Brain)

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Posterior limb of internal capsule R – White Background (Full Brain)

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Triplanar View – T1 Background

Triplanar View – Ghost Brain