To summarize what I understand from the Wikipedia article, the neurons involved are located between the T1 and L1 levels of the spinal cord. If you have a spina

To summarize what I understand from the Wikipedia article, the neurons involved are located between the T1 and L1 levels of the spinal cord. If you have a spinal injury above L1, some of those neurons are disconnected from the brain, and thus cannot activate normal responses (e.g. fight or flight).