Figure 1. The Functional Organization of Excitatory Neurons within the Dorsal Horn.
(A) Sensory inputs to the spinal cord dorsal horn display a modular organization: LI-IIo, pain and itch; LIIi-IV, touch; and LIV, proprioceptive.
(B) Excitatory neurons within the dorsal horn are organized into spatially restricted modules that are molecularly heterogeneous.
(C) Neuronal manipulation studies reveal that reflex behaviors are evoked by molecularly heterogeneous populations within discrete excitatory modules. *In the case of mechanical allodynia distinct circuits are activated in a context-dependent manner. Symbols represent molecularly distinct neuronal populations.