Perhaps others have a different view of this study and its widespread reception - I'm looking forward to reading Dr. Robert Zubrin's take - but the more I think about it as a layperson the stranger it seems any conclusions regarding space travel are drawn from it at all. Months of low level cosmic radiation was supposedly compressed into a single 10 to 100 minute "acute dose"? What would the equivalent of that be in terms of compressing normal everyday exposure to sunlight on Earth's surface over half a year - to say ten minutes? Would we conclude walking around outside on Earth's surface is sure to cause immediate death/severe burns, charred skin, blindness, "vascular alterations", spontaneous combustion, extreme anxiety/unpleasantness/total cognitive dysfunction or whatever several months worth of sunlight compressed into an "acute sunlight burst" would do???? LOL.

The second to last sentence of their report says it all:

"...one major caveat of our model is that mice were subjected to acute exposures with a single HZE species [iron particle]. It is not known how the CNS [astronauts] will respond to the complex and chronic low-dose GCR [galactic cosmic ray] environment of space. Moreover, astronauts will not likely be familial AD carriers [genetically predisposed to Alzheimer's]. Therefore, while many of the pathological processes are believed to be similar, this model does not reflect the complete human condition."

"Galactic Cosmic Radiation Leads to Cognitive Impairment"... generates worldwide headlines, whereas "After a Single Acute Burst Exposure to an Accelerated Beam of Iron Nuclei at Three and a Half Months of Age Transgenic Mice Brains Pre-Disposed to Alzheimer's Examined Only Four to Six Months Later Suffered Inflammation, with Males Showing Enhanced Plaque Pathology and Females Showing Absolutely Nothing Whatsoever" might lead the public to question how close this poorly written study cloaked in jargon corresponds to actual humans exposed over six months to much smaller increments of radiation would fare. Specifically whether "These pathological increases are particularly concerning for astronauts who will be exposed to [Galactic Cosmic Radiation] in upcoming deep space missions" actually means Mars pioneers will suffer dementia. Low level six month exposures might be worse than a single burst, or, with proactive medical treatment might not be a concern at all. We do not know.......at the very least the next similar study ought to expose mice over a longer period of time to radiation at lower doses and not euthanize females two months early. Hopefully this more accurate study will be conducted by persons more careful about the reception of their results in the space advocacy community, please.