Spinal Interneurons in the Control of Autonomic Function

Abstract The varied and complex roles of interneurons in the control of spinal cord function have provoked widespread interest in understanding how these neurons operate to enable appropriate and synchronised output from the spinal cord. This chapter focuses on the role of spinal interneurons in autonomic control and examines their properties, morphology, inputs and outputs. The location, neurochemical diversity, and firing patterns of spinal presympathetic interneurons suggest diverse roles for these interneurons while changes in these neurons after spinal cord injury may indicate their importance in the pathological changes occurring in this condition. Parasympathetic interneurons play roles in the precise orchestration of specific reflexes, such as those involved in bladder and bowel control, which is reflected in the lack of overlap of interneurons sub-serving different functions. Those interneurons that do show a less specific output may only be activated in unusual circumstances or conditions.