Dorsal root ganglia

The dorsal root ganglia are a collection of cell bodies of the afferent sensory fibers in a dorsal root of a spinal nerve, lying in the intervertebral foramina (Figure 1). These ganglia allow for fast reflexes before pain signals even reach the brain, although if the stimulus continues, eventually the brain is also triggered, leading to the sensation of pain.

Figure 1. Spinal cord (light red) with several dorsal root ganglia (yellow) lying in the intervertebral foramina (grey).