Botulinum Toxin as a Neuro-Relearning Drug Tool in Motor Paralytic Disorders

R.   Venkata   Krishnan

doi:10.2174/157488509788185169

Abstract

The clinical use of Botulinum toxin (BoTx) in motor paralytic disorders until now is limited to spasticity relief in isolated spastic muscle/s. This paper advocates that BoTx should be used as a neuro-relearning tool that can significantly improve recovery in motor paralytic disorders. BoTx generates redundant numbers of synapses at motor endplates and at spinal motoneuron-interneurons. It facilitates muscle activity-dependent synapse competition at these two sites. Redundancy and competition-based selection of synaptic connections are naturally occurring learning- related plasticity events during infant motor learning- now familiarly known as competitive-learning. Thus when injected in small doses to multiple muscles of a paralyzed limb, BoTx can recreate and replay those competitive-learning processes in the learningresistant paralyzed brain centers. Computational modeling, humanoid robot, and animal studies reveal that motor re) learning can be significantly faster if competitive-learning mechanisms are employed in the paralyzed system. A treatment protocol is presented that aims to keep the paralyzing effects of BoTx minimized while prolonging relearning duration. Recent clinical studies strongly attest that small-dose; multi-muscle, repeat regimens improve function. The principal objective of the present paper is that future multi-muscle clinical studies will take note of the relearning properties of BoTx and make full utilization of this therapeutic effect.

Keywords: Botulinum toxin, cerebral palsy, motor paralysis, spinal cord injury, stroke, traumatic brain injury (TBI)