- The spinal cord controls automatic responses through the "stretch reflex", which is the contraction that occurs when muscles flex 
- This occurs through e negative feedback loop, where muscle is stretched, and afferent muscle fibers are excited (stimulate electrical impulse) and (in turn) excite the motor neurons 
- The motor neurons then provide a negative feedback to the muscles to stop stretching, and work against the opposing force causing the muscle stretch 
- The spinal circuit will regulate the input to the muscle spindle

Smith College

- Motor neurons control the beginning, end, and organization of muscle movement  
- The spinal cord is involved in motor neuron input
- Therefore, in order to understand how movement is coordinated, the spinal cord's organization (as well as ways in which its disrupted/ how it interacts with the brain) must be understood

Spinal Cord in Controlling Body Movement

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

Spinal Cord and Automatic Response 

- Rhythmic movements (ex. beating wings, swinging legs) are described as the more complex movements compared to the automatic response
- The central pattern generator is a type of neural circuitry is responsible for this type of movement
- This circuitry is generated by the spinal cord, and is activated/ regulated by the brain 

Spinal Cord and Rhythmic Movements

Spinal cord injuries disrupt the communication pathway between the brain and the body. When a specific segment of the spinal cord is damaged, all segments below the point of injury are disconnected from the brain, leading to paralysis. The nature of the paralysis and reflex activity can vary; complete severance may cause flaccid paralysis and a loss of reflexes, whereas injuries where the tissue remains intact can lead to abnormally strong reflexes due to the loss of inhibitory signals from the brain.

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