Spasticity and Its Contribution to Hypertonia in Cerebral Palsy

Figure 2

The major excitatory (red lines), inhibitory (blue lines), and processing (black lines) pathways involved in the reflex regulation contributing to normal trunk and limb muscle tone. Pathways numbered (1) and (2) travel first through interneurons before synapsing with alpha- (-) motor neurons. GTO: Golgi tendon organ. Some extrapyramidal tracts (not shown in this figure) also contribute to the maintenance of normal muscle tone and not all pathways shown are necessarily involved in increased stretch reflex due to spasticity.