Central pattern generators (CPGs) theorized to coordinate locomotor activity in humans are located in which region of the spinal cord?

Central pattern generators (CPGs) theorized to coordinate locomotor activity in humans are located in which region of the spinal cord?

• A. Cervical enlargement (C3-C5)
• B. Thoracic segments (T6-T10)
• C. Lumbosacral segments
• D. Conus medullaris only (S3-S5)

Answer: (C)

Locomotor rhythm is generated by neural networks in the spinal cord called central pattern generators, and in humans these circuits reside in the lumbosacral segments. This region contains the lumbar enlargement that coordinates the hindlimbs, producing the alternating flexion and extension patterns needed for stepping. Even without brain input, these lumbar circuits can generate rhythmic locomotor activity, with sensory feedback shaping the pattern. The other regions have different primary roles: the cervical enlargement serves the arms, the thoracic segments mainly handle trunk control and autonomic functions, and the conus medullaris contains sacral nerve roots rather than the primary locomotor circuitry.

Locomotor rhythm is generated by neural networks in the spinal cord called central pattern generators, and in humans these circuits reside in the lumbosacral segments. This region contains the lumbar enlargement that coordinates the hindlimbs, producing the alternating flexion and extension patterns needed for stepping. Even without brain input, these lumbar circuits can generate rhythmic locomotor activity, with sensory feedback shaping the pattern. The other regions have different primary roles: the cervical enlargement serves the arms, the thoracic segments mainly handle trunk control and autonomic functions, and the conus medullaris contains sacral nerve roots rather than the primary locomotor circuitry.