Ventral posterior inferior nucleus

The ventral posterior inferior nucleus (VPI) of the thalamus is a relatively small sensory relay region associated with the ventral posterior thalamic complex, generally located inferior (ventral) to the VPL and VPM nuclei.

Processing of pain and temperature-related information

The ventral posterior inferior nucleus VPI receives sensory information from ascending anterolateral system pathways, including spinothalamic inputs carrying nociceptive and thermal information. Compared with the VPL and VPM, the VPI is particularly associated with the processing and integration of pain and temperature-related somatosensory information, although its sensory connections are more complex than those of a simple modality-specific relay.

Its thalamocortical projections reach somatosensory cortical territories. Experimental and anatomical studies also describe connections with regions involved in higher-order sensory processing, including the secondary somatosensory cortex and insular-related cortical areas.

Functional correlates (VPI, VPL, and VPM nuclei)

Functionally, the ventral posterior inferior nucleus VPI contributes to the thalamic processing and cortical transmission of somatosensory information, particularly nociceptive and thermal signals. The VPL predominantly relays somatic sensation from the contralateral body, the VPM predominantly relays somatic sensation from the contralateral face, whereas the VPI participates more broadly in integrative somatosensory and nociceptive processing.

Clinical correlates

Lesions affecting VPI region as part of the ventral posterior thalamus may contribute to contralateral sensory disturbances and central post-stroke (thalamic) pain.