Central thalamic radiation

The central thalamic radiation is a group of ascending thalamocortical projection fibres that connect the ventral and lateral regions of the thalamus with central and parietal regions of the cerebral cortex. It includes important somatosensory projections from the ventral posterolateral (VPL) and ventral posteromedial (VPM) nuclei to the primary somatosensory cortex of the postcentral gyrus.

From the thalamus, these fibres pass laterally through the posterior limb of the internal capsule and then fan superiorly through the corona radiata toward their cortical destinations. They therefore form an important component of the projection fibres within the internal capsule's posterior limb.

These fibres carry somatic sensory information from the contralateral side of the body and face, including touch, pressure, pain, temperature and conscious proprioception.

Difference between superior and central thalamic radiation fibres

The terms superior and central thalamic radiation come from different naming systems, but they include some of the same physical nerve fibres. In particular, the somatosensory fibres that pass from the VPL and VPM nuclei of the thalamus, through the posterior limb of the internal capsule and corona radiata, to the postcentral gyrus may be described as part of the central thalamic radiation in one classification and as part of the superior thalamic radiation in another.

So, the overlap is not just that the two pathways are close to each other; some of the same fibres are being given different group names. However, the terms should not be treated as completely interchangeable because the boundaries and additional fibres included in each group vary between anatomical classifications.