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Please enter your questions into the chat! Dr. German has 2 fantastic postdocs (Dr. Mayerl and Dr. Adjerid) who will be answering questions… and I will also be selecting some thought provoking questions for our speakers!
Maybe RLN especially important for feedback and comparison to efferent copy?
Thomas E. Dick
why no 5s nor 6s what are these deficits and are the unrelated to the RLN
Do the infants with RNL lesion have the cough reflex after aspiration?
My clinical experience has seen both silent aspiration and aspiration with cough.
Whats the timing of RLN development? Is it underdeveloped in these 22 weekers we have here that really have aspiration issues?
Cough is developmental- not sure when it is first seen in the pig.
Great Question Thomas. In the infant pigs, we rarely see any scores of 5 or 6, regardless of if it's an RLN lesion, SLN lesion, or even a preterm infant. One of the issues is that the infant pigs are basically only silently aspirate, and then will cough at the end of their feeding session, rather than stop feeding to cough
We can see coughing as early as one day after the pigs are born when they're experiencing lots of aspiration (at the conclusion of a feeding bout)
Thomas E. Dick
It lookedllike the swallow occurred in the postinspiratory period with no diminution of inspiratory duration
Have you ever studied piglets that are suckling at the mother’s teat, rather than on an artificial nipple?
Do you know if when coughing there is an inspiration for every expiration or do they take one inspiration and several expirations as they cough to a lower lung volume?
Great question Denise, we haven't done that yet, although we do currently have a grant proposal in at NIH to do just that, so stay tuned!
Really interesting thought Nick! We haven't looked into that explicitly, as it's somewhat hard to do because once the pigs finish eating they start running around so it's hard to measure. From what I recall after just feeding them and watching them afterwards myself, it seems as though they take one inspiration for every expiration, but that's just from us listening to them, not actually measuring breathing with a plethysmograph or thermocouple
Are these results consistent to models of aspiration in the elderly population?
In human infants with RLN injury, we will see vocal cords that are paralyzed in different positions, and there is some thought that aspiration severity is related to that position. Have you seen anything like that with the pigs?
Do pigs swallow during sleep?
In newborn lambs, one inspiration for every expiration with a cough
Have you seen/looked at upper esophageal sphincter opening timing too?
Laambs swallow during sleep, and there are bursts of swallows during REM sleep (no burst. During NREM)
only a little but we did see difference in UES function in our lesioned pigs
Jessica, that's an interesting question about vocal cord paralysis in different positions. We haven't looked at it explicitly, but we did see that the individual response to RLN lesion was hugely variable, so that could be part of a mechanism explaining some of those interindividual differences in response!
Yes, the infant pigs are swallowing during sleep, I imagine that it's probably something similar across mammals
How does the genioglossis EMG activity align with the respiration traces?
Thank you Dr. German, Christopher and Francois - very cool research!
Look at those nuggets!!!
Thomas E. Dick
the piglets are not in numerical orde!
Haha yeah when they're first born we pair strong breathers with weak breathers so they get mixed up quick!
for people doing human work:7 days ~ 1-2 months postnatal for humans17 days ~ 6-9 months postnatal for humans
Yes! I was just thinking about this Vose.
Rebecca and Francois—I have to join another zoom meeting, but wanted to thank you both for the terrific presentations. I learned a lot!
Are there differences in the swallowing if piglets are weaned earlier vs later? Thinking about differences in weaning infants at 4 months in modern infants vs 3-4 years in hunter-gatherer societies.
Great question Denise - We haven't weaned pigs at too many different ages, they are quite recalcitrant to stop drinking milk any earlier than what Francois presented! That is a really interesting idea though
Can you give us the age comparison again? How “preemie” is 7 days for a pig? :)
7 days early = 30 - 32 weeks gestation
Cool! Thanks Chris!
This is SO validating to see as a clinician!
Relevant papers from Francois Presentation:weaning - https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0942maturation of swallow volume and safety - https://www.nature.com/articles/s41390-019-0624-0Relationship between bolus size and swallow safety - https://doi.org/10.1007/s00455-020-10118-xPreterm resp-swallow coordination - https://journals.physiology.org/doi/full/10.1152/japplphysiol.00101.2019
One of the leading causes of death in Alzheimer's is aspiration pneumonia, do you know what happens with breathing-swallowing coordination?
Wonderful talks! I've learned a lot. Thank you! I have to sign off now
Hi, everyone! Feel free to turn your cameras back on for the Q&A session. :)
Is it possible that the swallow movement that happens in utero, could be present for the same function as the in utero respiratory movements, to prepare the infant for breathing the air after they born?
It seems to me it is important to realize that the results presented are for nutritive swallowing. For non-nutritive swallowing, at least in lambs, swallowing-breathing coordination is identical in preterm and full-term lambs.
Infant studies....The inspiratory onset is a mechanical one. Any consideration of neural or EMG activity (diaphragm or alae nasi, a muscle that activates before the diaphragm). The negative pressure to suck is created in the oral cavity and then the bolus travels around or through the valeculla to the esophagus. How about negative pressure in the oral cavity and negative pressure in the chest (a sum total of inspiratory activation). no microphone on this computer
We are collecting comparative data on NNS vs. NS in June.
Do you see variation in rhythm - suckle/breath/suckle breath/suckle/breath - versus - suckle/suckle/suckle/breath etc?
Owen Bamford once sent me traces of each of these in humans
Interestingly, preterms are often swallowing milk during central apnea; I mean several swallows during one several second duration. A different strategy in order not to aspirate
Interestingly, preterms are often swallowing milk during central apnea; I mean several swallows during a few second-duration apnea. A different strategy in order not to aspirate in preterms
It’s the same in human infants
It would be interesting to know more about how piglet chest wall development correlates with humans. Human babies use that SSB pattern in part because they structurally have shallow diaphragm shapes and lower tidal volumes. They also desaturate more easily, so can’t hold their breath for very long.
But their chemoreceptors are less responsive so is that right?
SSB = suck-swallow-breathe
Thank you so much!!!
Great stuff guys!
Rebecca is also hiring a postdoc
Great talks Dr. German and Dr. Gould!
Thank you very much
Thank you!! This was fantastic!
Thank you for the very interesting talks!
Thank you for the great talks and discussion
Thank you so much brilliant