Thanks for posting this Andy, very interesting. I do have a couple of comments though. Interpreting cognitive impairment via flicker-fusion rates, is a bit speculative. Flicker-fusion perception can be influenced by both peripheral (retinal and optic nerve neurons) and central (brain) processes. The circuits involved in processing information in the retina (and transferring that information to the brain) and the circuits involved in processing information in the brain rely on different neurotransmitters and mechanisms. Thus changes in flicker-fusion perception does not necessarily indicate cognitive (e.g. problem solving) impairment.
With that said, I do find the fact that the perceptual changes persisted after the dive interesting and perhaps not surprising. Whatever the neural mechanism, cognitive impairment from narcosis results from increased tissue loading of inert gasses. Every diver knows that ascending does not instantly clear tissues of residual inert gasses. Thus, we might expect lingering effects of increased inert gas loads. I also find it interesting that they mention previous studies in rats showing that increased PN2 increases GABA activity. GABA is an inhibitory neurotransmitter who's job is to slow down or stop activity in neural circuits. Regardless of how well these finding translate into lingering cognitive impairment from narcosis, it's interesting and certainly something to keep in mind. Thanks for sharing!
