Spinal ascending pathways for somatosensory information processing

The somatosensory system detects and processes diverse types of information from the external and internal environment, and is critical for animal survival. The ascending pathway originating from spinal projection neurons is crucial for transmitting the various subtypes of somatosensory information to multiple brain areas, and is involved in perception, emotion, motivation, and cognition. Although most spinal projection neurons target contralateral brain regions, spinal projection neurons with bilateral targets have also been described. The diverse projection patterns of spinal projection neurons are likely determined by their molecular properties. Given the heterogeneity of spinal projection neurons, it is possible that different subpopulations of spinal projection neurons and spinal ascending pathways are differentially involved in diverse submodalities of somatosensation and its distinct components. The somatosensory system processes diverse types of information including mechanical, thermal, and chemical signals. It has an essential role in sensory perception and body movement and, thus, is crucial for organism survival. The neural network for processing somatosensory information comprises multiple key nodes. Spinal projection neurons represent the key node for transmitting somatosensory information from the periphery to the brain. Although the anatomy of spinal ascending pathways has been characterized, the mechanisms underlying somatosensory information processing by spinal ascending pathways are incompletely understood. Recent studies have begun to reveal the diversity of spinal ascending pathways and their functional roles in somatosensory information processing. Here, we review the anatomic, molecular, and functional characteristics of spinal ascending pathways. The somatosensory system processes diverse types of information including mechanical, thermal, and chemical signals. It has an essential role in sensory perception and body movement and, thus, is crucial for organism survival. The neural network for processing somatosensory information comprises multiple key nodes. Spinal projection neurons represent the key node for transmitting somatosensory information from the periphery to the brain. Although the anatomy of spinal ascending pathways has been characterized, the mechanisms underlying somatosensory information processing by spinal ascending pathways are incompletely understood. Recent studies have begun to reveal the diversity of spinal ascending pathways and their functional roles in somatosensory information processing. Here, we review the anatomic, molecular, and functional characteristics of spinal ascending pathways.