Kappa opioids inhibit spinal output neurons to suppress itch.

Itch is a protective sensation that drives scratching. Although specific cell types have been proposed to underlie itch, the neural basis for itch remains unclear. Here, we used two-photon Ca imaging of the dorsal horn to visualize neuronal populations that are activated by itch-inducing agents.

The functional and anatomical characterization of three spinal output pathways of the anterolateral tract.

The nature of spinal output pathways that convey nociceptive information to the brain has been the subject of controversy. Here, we provide anatomical, molecular, and functional characterizations of two distinct anterolateral pathways: one, ascending in the lateral spinal cord, triggers nociceptive behaviors, and the other one, ascending in the ventral spinal cord, when inhibited, leads to sensorimotor deficits. Moreover, the lateral pathway consists of at least two subtypes.

Identification of a convergent spinal neuron population that encodes itch.

Itch is a protective sensation that drives scratching. Although specific cell types have been proposed to underlie itch, the neural circuit basis for itch remains unclear. Here, we used two-photon Ca imaging of the dorsal horn to visualize the neuronal populations that are activated by itch-inducing agents.