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Scientists had hypothesized that lampreys might use body-sensing feedback (called proprioception or kinesthesia) to guide their movements in addition to descending neural connections in the spinal cord. Morgan had reached out to discuss this with an old friend of hers from MBL, , Associate Professor of Biology at Tufts University and former MBL Whitman Center Investigator. Eric was already collaborating with Lisa Fauci, a Professor of Mathematics at Tulane University, and Christina Hamlet, who was a co-mentored postdoc at Tulane.

Tytell, Fauci, and Hamlet were using mathematical models to mimic movement in lampreys. They teamed up to “see if we could model some of the effects of sensory feedback on swimming behavior in lampreys,” said Hamlet, who is currently an Assistant Professor of Mathematics at Bucknell University.

The team began playing around with different scenarios of spinal injured lampreys – including both biologically plausible and implausible ones – all of which assumed no neural regeneration across the spinal cord lesion. This is the utility of modeling, said Hamlet, “We can break things that you can't break in biology.” The model took into account the curves and stretch created in the body above the lesion and sent that information to the rest of the body through the muscles, not the spinal cord.

Even with a moderate amount of sensory feedback, the models showed a surprising recovery of swimming patterns in the biologically plausible models. Stronger sensory feedback led to even greater improvement.

Because lampreys do grow back some of their neurons after a lesion and therefore have descending command from the brain to drive movement, they may need even less sensory feedback than the model. The team hopes to add neuronal regeneration into the model and test how that affects movement and interacts with sensory feedback.