The project began with the acquisition of all certifications and licenses for performing preclinical studies and the training on in vivo spinal cord research. This was accompanied by an extensive study of literature in the field, which led to a fundamental review paper about the neurophysiological mechanisms of spinal neuromodulation.
Then, I used terminal experiments to design new protocols of electrical stimulation and evaluate the impact of acute stimulation in modulating and restoring spinally-induced motor responses from the rat hind limbs. I delivered this complex pattern through a multi-electrode planar epidural array recently devised at UCLA, which was further improved using new materials and coatings to maximize fidelity of charge transfer.
Then, DS was continuously delivered to multiple segments of the spinal cord, at very low intensity and with opposite cathode/anode location, to assess DS efficacy and compare it to standard trains of stereotyped pulses currently used in experimental research and clinics. In fully-anesthetized neurologically-intact animals, DS modulated the amplitude of motor responses, increased spinal network excitability and potentiated weak input from the brain to the cord. Moreover, acute supply of DS to spinally injured rats restored considerable hindlimb activity. DS was then delivered to animals with a chronic spinal cord injury to explore the intrinsic mechanisms of motor output modulation by spinal neuronal circuits and the pathophysiology of an acute spinal cord injury.
DS proved as a reliable first strategy to limit the loss of functions following a spinal cord injury, opening a new vision about the early management of spinal cord injuries.
In addition, DS facilitated cortico-spinal connectivity and, when associated with locomotor training, it promoted plastic rearrangements of interneuronal networks in animals with a spinal injury.
The new interface also allowed recordings of electrical potentials from the surface of the cord during peripheral nerve stimulation, demonstrating the selectivity of each independent electrode of the array in detecting neuronal activity and thus identify the best sites to act upon to optimize stimulation for neurorehabilitation.
The results led to one published review, three manuscripts that are deemed to be published during this year, various seminars and presentations in world-class conferences, as well as an international network of collaborations with world-class laboratories to nourish promising research and scientific multicenter studies. Finally, the important advancements obtained in spinal cord research have high potentials of being proposed soon to clinical researchers.
