In terms of biomedical questions, we investigate:
1) the mechanisms controlling axonal collateral sprouting (growth of non-injured axons) in the adult nervous system, particularly considering how these mechanisms contrast with those of axonal regeneration (growth of injured axons);
2) the mechanisms and consequences of sensory neuron responses to damage of peripheral tissue (e.g., skin, muscle, viscera), particularly contrasting this with the response of sensory neurons to nerve injury;
3) the effects of spinal cord injury and post-SCI plasticity-inducing treatments on the function of motor and sensory neurons.
These hypothesis-driven projects are well-coordinated when viewed in the context of my long-term vision – understanding how sensory input to the spinal cord below an injury influences the function of the remaining circuitry. It is my proposition that the combined effects of spinal cord injury and inflammatory and/or tissue-damaging secondary conditions (e.g., systemic inflammation, pressure sores, bladder infection, bowel impaction) act in concert to induce “circuit dysfunction” in the spinal cord caudal to an injury due to an unchecked, overactive, and highly plastic spinal nociceptive system. Unfortunately, SCI-related secondary conditions are rarely considered in basic neuroscience research, in spite of their high degree of clinical relevance and importance to the SCI community. On the other hand, the status of spinal circuits below an injury is a topic of a great deal of basic science study, but principally in the context of acute lacerations intended to determine the role of specific tracts, and much less-so in the context of clinically-modelled SCI. The status of these circuits after SCI is increasingly more important with the accumulation of data demonstrating the efficacy of activity-dependent task-specific training (i.e., physical therapy), and the reliance of that therapy on both appropriate sensory input and “healthy” caudal spinal cord circuitry.
Jeffrey C. Petruska, Ph.D. Website
See the story “A new player revealed in nerve growth process” at this LINK from the University of Louisville School of Medicine.