Wind-up is a frequency-dependent increase in the response of spinal cord neurons, which is believed to underlie temporal summation of nociceptive input. However, whether spinoparabrachial neurons, which likely contribute to the affective component of pain, undergo wind-up was unknown. Here, we addressed this question and investigated the underlying neural circuit. We show that one-fifth of lamina I spinoparabrachial neurons undergo wind-up, and provide evidence that wind-up in these cells is mediated in part by a network of spinal excitatory interneurons that show reverberating activity. These findings provide insight into a polysynaptic circuit of sensory augmentation that may contribute to the wind-up of pain's unpleasantness.
An excitatory network that shows reverberatory activity contributes to wind-up in lamina I spinoparabrachial output neurons.
aDepartment of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
bPittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States. Dr. Omori is now with the Toray Industries, Inc, Pharmaceutical Research Laboratories, Kamakura, Kanagawa, Japan
Corresponding author. Address: 200 Lothrop St., W1456 BST, Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213. Tel.: +1 412-624-9178; fax: 412-648-1441. E-mail address: firstname.lastname@example.org (S.E. Ross).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
H.R. Koerber and S.E. Ross contributed equally to this work.
Received November 06, 2017
Received in revised form January 25, 2018
Accepted February 20, 2018