Neuroanatomy, Substantia Gelatinosa

The substantia gelatinosa of Rolando (SGR) is a specialized region of grey matter located within lamina II of the dorsal horn of the spinal cord (see . Spinal Cord Cross-Section Showing Substantia Gelatinosa and Nuclei). This region serves a central role in modulating nociception, temperature, and crude tactile sensation. The structure is eponymously named for Italian anatomist Luigi Rolando, who first described it in the early 19th century. The SGR exhibits a translucent appearance due to a dense network of unmyelinated fibers and abundant neuropil. Anatomically, the SGR extends along the entire length of the spinal cord and continues rostrally into the caudal medulla, where it becomes continuous with the spinal nucleus of the trigeminal nerve. The structure receives primary afferent inputs predominantly from C and Aδ fibers originating in the dorsal root ganglia (DRG), which convey nociceptive and thermal information. The region also receives descending modulatory input from supraspinal centers, including the brainstem. Projections from the SGR target adjacent regions of the dorsal horn and contribute to the anterolateral (spinothalamic) pathway, transmitting processed nociceptive signals centrally. The SGR acts as a key modulatory center in pain processing by integrating peripheral inputs with descending signals, consistent with the gate control theory of pain.