I’ve tried to compress two topics into one talk … first I’m going to talk about training — and you see the small print “in animal models.” We’re starting with Rehab in Rats.
Why study this? I want to understand what happens in the nervous system when it uses training to recover. We used to do this elaborate treadmill training with rats, but then we started using sugar pellets. We’d spend five weeks ahead of time having them learn how to do it, but then it was much easier than the treadmill effort because we could do just a very small injury to see how much plasticity there was.
And they did very, very well — got a huge recovery. So what can we learn. What we want to know is how exactly plasticity works post injury.
He says they had an idea that inflammation might actually help, because naturally occurring inflammation does coincide with effective recovery. They gave their rats a little fever. A tiny fever. Saw nothing change.
And then a student happened to invent a new training device, which led to this discovery: an increase in training efficacy was the result of an increase in training intensity. One of the things they had to work against was that rats have a talent for compensating. They come up with their own strategies to work around their deficits.
At the level of neurons, they can use stains to figure out what’s going on during plasticity. And what they saw was that training doesn’t cause growth, but it does show that growth can be used to target areas of the brain.
New subject … chronic capillary constriction after SCI. There are cells called pericytes that clamp down on capillaries after an injury, which causes the tone in the capillaries to change. This means poor circulation and poor oxygenation.
They verified this finding with more experiments — but why do we care? Because either by giving extra oxygen or by eliminating the pericytes, both sensation and mobility improve.
Conclusion is that you can excite the spine in more ways than just with epistim, and manipulating the flow of oxygen is one of them. Still, we need to be careful that adding oxygen will not also do something negative, like increasing pain.
This is something we didn’t know before, but now we do. This is a new avenue for research.
Question/comment: Good talk, easy to understand. As a person with an incomplete SCI, I’ve lived with a correlation between things that I eat (sugary foods that cause inflammation) and things like pain and spasticity. Do we understand the mechanism?
We don’t. We don’t understand the mechanism.
Followup: About the lack of oxygenation in the cord, it’s interesting that later someone is going to talk about reducing oxygen …
And I think that reducing oxygen temporarily has a beneficial effect because it causes more blood flow … that’s my hypothesis.
Question: Could any excitation of the central nervous system have the same effect as mild inflammation in terms of helping with training?
(He said it longer than this) Yes.
Followup: How are you getting more oxygen into your subjects?
We trick them. It’s just a proof of principle …
Followup: I’d challenge you to try yoga breathing.
Once we’ve proven the point that it’s really happening, we can go wild.
Question: There’s both good and bad inflammation. Some promotes growth and some doesn’t.
(sorry, missed the answer)
Question: How about incorporating the hyperbaric chamber?
Yes, but we don’t have one.