transecting the dorsal roots of the spinal cord that innervate the animal's limbs, which impedes transmission of sensory information while keeping motor innervation of muscles intact. In contrast, immobilization involves injecting an acetylcholine inhibitor, which impedes the transmission of motor signals while sensory input is unaffected.) The complexity of gait arises from the need to adapt to expected and unexpected changes in the environment (e.g., changes in walking surface or obstacles). Visual, vestibular, proprioceptive, and tactile sensory information provides important feedback related to gait and permits the adjustment of a person's posture or foot placement depending on situational requirements. When approaching an obstacle, visual information about the size and location of the object is used to adapt the stepping pattern. These adjustments involve change in the trajectory of leg movement and the associated postural adjustments required to maintain their balance. Vestibular information provides information about position and movement of the head as the person moves through their environment. Proprioceptors in the joints and muscles provide information about joint position and changes in muscle length. Skin receptors, referred to as exteroceptors, provide additional tactile information about stimuli that a limb encounters. Gait in humans is difficult to study due to ethical concerns. Therefore, the majority of what is known about gait regulation in humans is ascertained from studies involving other animals or is demonstrated in humans using functional magnetic resonance imaging during the mental imagery of gait. These studies have provided the field with several important discoveries. Locomotor centers There are three specific centers within the brain that regulate gait: Mesencephalic Locomotor Region (MLR)- Within the midbrain, the MLR receives input from the premotor cortex, the limbic system, cerebellum, hypothalamus, and other parts of the brainstem. These neurons connect to other neurons within the mesencephalic reticular formation which then descend to the via the ventrolateral funiculus to the spinal locomotor networks. Studies where the MLR of decerebrate cats have been stimulated either electrically or chemically have shown that increased intensity of stimulation has led to increased speed of stepping. Deep brain stimulation of the MLR in individuals with Parkinson's has also led to improvements in gait and posture. Sub thalamic Locomotor Region (SLR)- The SLR is part of hypothalamus. It activates the spinal locomotor networks both directly and indirectly via the MLR. Cerebellar Locomotor Region (CLR)- Similar to the SLR, the CLR activates the reticulo-spinal locomotor pathway via direct and indirect