Building Somatosensory Circuitry

Sensory information that pinprick hurts! the silk is smooth travels from our extremities to the brain via the neurons of the somatosensory system. These sensory neurons lie in the dorsal horn of the spinal cord and carry information about the quality, intensity, and position of individual sensations to other segments of the spinal cord and to specialized centers in the brain, notably the cerebellum and thalamus. These centers process and integrate these messages. The somatosensory system accurately handles countless sensations from both our right and left sides and relays this information to both sides of the brain. When the spinal cord is damaged, people lose not only muscle function but also sensation and the coordination between sensory perceptions and the muscles that that were controlled by the somatosensory system. In addition, injury to somatosensory neurons can cause altered sensations, such as chronic pain. To repair this damage, scientists must first understand both the signals and mechanisms that generate this complex circuitry during embryonic development and the relationship between the arrangement of the circuits and their proper function.

In this study, Dr. Dodd will focus on the evolution of one subset of spinal relay neurons called the D1 subpopulation. She already has generated important data on these neurons, which seem to be involved in sensing pain and the position of our arms and legs. She and her research team identified two genes that are normally activated in D1 neurons and showed that these genes play key roles in guiding D1 axons to their final destination. Dr. Dodd is hopeful that by manipulating these genes, she can alter the pathway and targets of D1 neurons. She will first trace the D1 circuitry as it develops and then will try to precisely what specific neurons do and selectively deactivate them in an otherwise normal animal model. She predicts that this approach will show how an individual circuit forms and functions and how changes in one isolated circuit affect the establishment of others and the way they interact to transmit information. Her findings could be critical to rebuilding the somatosensory system after an injury and eliminating the chronic pain that often plagues people living damaged spinal cords.