Thread by @boeslab

Is the wakefulness-promoting, consciousness-enabling influence of the brainstem left-lateralized in humans?

Seems unlikely, right? In 2016 we did a lesion study of coma and our results suggested a left lateralization to a dorsolateral pontine tegmentum arousal-promoting region.

This was a small enough sample I think we all assumed the apparent laterality could have been by chance.

Ever since this paper Joel Geerling (@geerling_lab) and I have been collecting brainstem lesion cases @uiowaneuro in search of counter evidence that would challenge this lateralization hypothesis.

A few years in now and I’d say we’ve seen more supportive evidence for the left lateralization of arousal circuitry in humans than we have any clear-cut cases of counter evidence. But this is with a huge caveat...

that coma from small brainstem lesions is exceptionally rare, and most coma-causing lesions cross the midline. It’s not really a question that is well-suited for a single site study… maybe better suited for the wide world of #neurotwitter to weigh in on.

What have you got neurotwitter - any insights on the topic? Any examples of right-sided focal brainstem lesions that cause coma and help lay the laterality issue to rest.

More to read here:
Excellent thread by @dbfisch on the 2016 brainstem lesion study.

https://twitter.com/dbfisch/status/1513607935422697478?s=20

Recent article from @geerling_lab on the epic century-long search for the elusive brainstem wakefulness-promoting circuitry

A Century Searching for the Neurons Necessary for Wakefulness ncbi.nlm.nih.gov/pmc/articles/P…

A potential counter example: Pt TG from @josef_parvizi & @damasiousc's excellent 2003 paper as a right-lateralized lesion reported to cause complete unresponsiveness for up to 2 hours per the outside hospital report. But on arrival to UIHC was opening eyes to command.

Neuroanatomical correlates of brainstem coma pubmed.ncbi.nlm.nih.gov/12805123/