Our Research Framework
Regeneration is an Emergent Property
Tissue regeneration is not a single genetic switch. It occurs in a behaving animal with a nervous system, an immune response, and a history of movement — and all of those things interact with the wound. We study those interactions directly.
The diagram maps our primary research interests. Structural and behavioral recovery sit at the center because they are the outcomes we can measure, and because measuring them well is what makes the other questions tractable.
The Biology of Species That Heal Without Scarring
Most regeneration research begins at the wound. We begin earlier. Before we study injury, we characterize the natural physiology, behavior, and sensory biology of the species we work with because restoration can only be measured against a known baseline.
Memory of Spiny Mice
Spiny mice show enhanced learning and memory relative to standard laboratory mice. We are characterizing this cognitive baseline in uninjured animals to establish what is normal before studying how injury and regeneration affect it. This work is supported by an internal PrePI grant from Kennesaw State University, with Dr. Vishnu Suppiramaniam and Dr. Erica Holliday.
Olfactory and Tactile Sensation in Salamanders
Before we can ask whether a salamander recovers its sensory abilities after injury, we need to know what those abilities are. We are characterizing olfactory and tactile sensation in salamanders as a baseline for future studies of sensory recovery. This work is supported by an internal Mentor Protege grant from Kennesaw State University, with Dr. Todd Pierson.
Key Publications
- Varholick (2025). "Bite wounds and dominance structures in male and female African spiny mice..." Animals. Link
Regeneration, Adaptation, or Both?
After injury, regeneration and adaptation occur simultaneously. Tissue regrows while the nervous system rewires, sensation redistributes, and behavior changes to compensate. Both processes can restore function. The problem is that they are not distinguishable by outcome alone. We study the quality of structural recovery — nerve fiber density, muscle architecture, target reinnervation — to ask whether what regrew is sufficient to explain what recovered in terms of structure and function.
Quality of Regeneration
Regenerated tissue is not always equivalent to the original. We quantify structural recovery at the level of individual nerves, muscle fibers, and skin architecture to determine how completely the original tissue is restored and whether that completeness varies within a species, within an experiment, and across injury types. Variability in structural recovery is not noise — it is the signal.
Does Structure Predict Function?
When sensation or movement returns after injury, the standard interpretation is that regeneration worked. We ask whether that interpretation is justified. Using behavioral assays alongside histological measures, we test whether the degree of structural recovery predicts the degree of functional recovery, or whether the two dissociate. Dissociation would indicate compensation. When structural quality predicts functional outcome, we can call it restoration. In most cases, it is likely both.
Closing the Gap in Human Nerve Repair
Peripheral nerve injuries affect over 20 million Americans annually, from trauma and surgery to diabetic neuropathy. Current treatments — autografts, engineered tissue, and synthetic conduits — can bridge a nerve gap, but functional recovery rates remain poor. Many patients live with permanent numbness, pain, or reduced motor control. The deficit is not in the nerve's ability to regrow axons. It is in the failure to regenerate the connective tissue architecture that guides them to the right targets and to mobilize anti-fibrotic agents that block the regrowth of axons.
Optimizing Peripheral Nerve Healing
Humans can regenerate single axons, but we fail to regenerate the complex neural architecture required for full sensation. Using the Spiny mouse whisker pad as a template, we are working to identify the signals required to guide peripheral nerves and regenerate the connective tissues that support them in humans.
The Missing Ingredient: Behavioral-Sensory Feedback
What makes spiny mouse nerve regeneration different from human outcomes? We hypothesize that active sensory feedback and behavioral engagement during healing are not passive consequences of recovery but necessary drivers of it. By identifying the critical windows when behavioral input most influences nerve guidance and target reinnervation, we aim to design biobehavioral rehabilitation protocols that complement surgical and molecular therapies.
Key Publications
- Varholick et al. (2025). "Spiny mice regenerate wounded whisker pad skin with whisker follicles..." npj Regenerative Medicine. PDF