Integration of sensory, spinal, and volitional descending inputs in regulation of human locomotion.

We reported previously that both transcutaneous electrical spinal cord stimulation and direct pressure stimulation of the plantar surfaces of the feet can elicit rhythmic involuntary step-like movements in noninjured subjects with their legs in a gravity-neutral apparatus. The present experiments investigated the convergence of spinal and plantar pressure stimulation and voluntary effort in the activation of locomotor movements in uninjured subjects under full body weight support in a vertical position. For all conditions, leg movements were analyzed using electromyographic (EMG) recordings and optical motion capture of joint kinematics.

Initiation and modulation of locomotor circuitry output with multisite transcutaneous electrical stimulation of the spinal cord in noninjured humans.

The mammalian lumbar spinal cord has the capability to generate locomotor activity in the absence of input from the brain. Previously, we reported that transcutaneous electrical stimulation of the spinal cord at vertebral level T11 can activate the locomotor circuitry in noninjured subjects when their legs are placed in a gravity-neutral position (Gorodnichev RM, Pivovarova EA, Pukhov A, Moiseev SA, Savokhin AA, Moshonkina TR, Shcherbakova NA, Kilimnik VA, Selionov VA, Kozlovskaia IB, Edgerton VR, Gerasimenko IU. Fiziol Cheloveka 38: 46-56, 2012).

[Non-invasive transcutaneous spinal cord stimulation facilitates locomotor activity in decerebrated and spinal cats].

It is known that spinal neuronal networks activated by epidural electrical stimulation (EES) can produce the stepping EMG pattern and control the locomotor behavior. At present study we showed that non-invasive transcutaneous electrical spinal cord stimulation (tESCS) applied to the lumbar-sacral enlargement can facilitate the locomotor activity in decerebrated and spinal animals. The comparison of the motor responses evoked by EES vs tESCS showed that both methods produce the locomotor patterns with close properties and similar reflex mechanisms.

Somatosensory control of balance during locomotion in decerebrated cat.

Postmammillary decerebrated cats can generate stepping on a moving treadmill belt when the brain stem or spinal cord is stimulated tonically and the hindquarters are supported both vertically and laterally. While adequate propulsion seems to be generated by the hindlimbs under these conditions, the ability to sustain equilibrium during locomotion has not been examined extensively. We found that tonic epidural spinal cord stimulation (5 Hz at L5) of decerebrated cats initiated and sustained unrestrained weight-bearing hindlimb stepping for extended periods.

Novel and direct access to the human locomotor spinal circuitry.

The degree of automaticity of locomotion in primates compared with other mammals remains unclear. Here, we examine the possibility for activation of the spinal locomotor circuitry in noninjured humans by spinal electromagnetic stimulation (SEMS). SEMS (3 Hz and 1.