28 Preganglionic sympathetic neurons arise from the thoracic and lumbar regions of the spinal cord. A) True B) False Solution The answer is True. Two types of neurons involved in the transmission of any signal through the sympathetic system: pre-ganglionic and post-ganglionic. The shorter neurorns are called as preganglionic neurons, which are originate from the thoracolumbar region of the spinal cord specifically at T1 to L2~L3.