The functional anatomy of lamina I and its role in post-stroke central pain

Abstract

Lamina I of the dorsal horn is an integral component of the central representation of pain and temperature sensibilities. The functional and anatomical characteristics summarized in the chapter demonstrate a strong correspondence of the lamina I projection system with clinical and imaging observations in humans. These characteristics indicate that the fundamental role of the lamina I projection system is to distribute modality-selective sensory information on the physiological status of the tissues of the body to a hierarchical network of sensory and homeostatic substrates involved in the maintenance and preservation of the integrity (or well-being) of the organism. Pain and temperature are functionally and anatomically intimately related because they inform the central nervous system about the condition of the tissues of the body. The lamina I projection system can be viewed as a set of ascending pathways that subserve enteroception, the sense of the condition (or health) of the body. The concept that both pain and temperature sensibilities are specific aspects of integrative enteroception provides a global perspective for understanding the integrative nature of pain and a new basis for understanding the clinical syndrome of post-stroke central pain.