Don’t be so thick
Theresa Harrison, Sandra Weintraub, M.-Marsel Mesulam, and Emily Rogalski at Northwestern University published an article in Journal of the International Neuropsychological Society (http://goo.gl/s5DKA) where they report using MRI to detect structural differences between normal volunteers and “superagers”. Superagers are elderly individuals who have the brain capacity of what we would expect from a much younger individual.
I like this publication because some MRI based research in neuroscience uses functional images to infer structural information and that is not the case here. I’ve discussed the differences between functional and anatomical images before. http://goo.gl/UTPK7
In the first figure, they show how the superagers performed on memory tests and their cortical thickness measurements relative to various groups. The red and yellow show significantly thinner regions.
My only complaint about the study is that there are very little details about the MRI parameters. They refer to a guide published in 2008.
The Alzheimer’s Disease Neuroimaging Initiative (ADNI): MRI methods.
CR Jack et al J Magn Reson Imaging. 2008 Apr;27(4):685-91.
http://www.ncbi.nlm.nih.gov/pubmed/18302232
Based on that, I’m guessing that the voxel dimensions they used were 1.3 X 1.3 X 1.2 mm. So when they say that the thickness maps generated can detect submillimeter differences between groups, I’m not buying it. You have a hard time detecting structural differences smaller than your voxel size. You can detect difference in functional images caused by regions much smaller than your resolution but that’s not the case here.
The last two images I shared are from the 2008 paper they referred to. The first is a good example of chemical shift, which I discussed here:
Medical Imaging 101 pt 3: MRI http://goo.gl/UVbiU
The second shows the effect of using an MRI protocol that was optimized for a different coil. The coil is the part that goes around the object to be imaged, a head coil in this case. They are comparing a single-element bird cage vs. a phased array coil. The phased array coil is a multi-channel coil that collects images simultaneously in smaller regions, like a group of single-element coils chained together. It allows you to go a lot faster but it’s complicated.
Finally, here is the ABC News video (http://goo.gl/G4MQz) and the news article from Northwestern University (http://goo.gl/nNJbE)
#CHMedicalImagingSeries
For #ScienceSunday ScienceSunday curated by Allison Sekuler Rajini Rao Robby Bowles and me.
What is super age
Superagers are individuals that do not appears as if they have aged mentally, i.e., they are still cognitively very sharp at 80 years old, for example.
Mz Maau I think the study is OK I just didn’t like the statement about thickness mapping.
Thanks for sharing! A very interesting study and even more interesting comments, thank you!
You are welcome Tommi Himberg
Good luck Peter Lindelauf Ask the radiologist for DICOM images if you want me to make some cool 3D surface renderings of your brain. We can start a private message for that.
Now to figure out the cause…
Sorry, I forgot it was for your neck. We can still probably do something neat.
The cause? J Dartt
There’s a lot of work showing that people “age” at different rates (that’s one of the things we study), so it’s interesting to see this sort of study. Of course, it’s just a correlation, so we don’t know if the brain differences are due to people being superagers, or if having the brain differences leads to superaging. There is always much more variability in performance on perceptual and cognitive tasks among senior participants than among typical university-aged participants. This is likely because people age at different rates, so biological age becomes less meaningful as we age. In fact, if you plot performance across subjects on a wide range of tasks as a function of biological age – things won’t line up at all. BUT if you plot performance backwards from time of death – bingo, much better predictions. This is called the terminal drop. Many functions (physiological, behavioural, perceptual, cognitive, etc.) all start to fall apart at the same time. Unfortunately/fortunately, when we are testing living participants, we only know their biological age, not how far they are from death, which makes studying aging much more challenging because of the incredible variability in performance/brain measures.
And, as Peter Lindelauf suggests, you can “teach older brains new tricks” – and there has been work suggesting that staying cognitively and socially and physically active enhances brain function as we age.
Thanks for the insight Allison Sekuler I’m so enthusiastic about in vivo imaging because it give us a chance to make these measurements, in vivo, longitudinally. How you correlate them is not my problem :-).
LOL Peter Lindelauf – glad to help.
The cause: chemical, genetic, environmental? What is it that these people are doing that makes them different?
Not my area of expertise, but would be interesting to find out.
J Dartt part of it is “exercising” your brain as Peter Lindelauf mentioned. The rest, diet, genetics, etc. is unknown.
Is there age-related thinning of some brain regions occurring naturally such that superagers show slower rates of thinning? Or do the superagers have thicker brain regions all along? I’m looking for a longitudinal study correlating aging to brain thickness …something that follows a group of subjects over a decade or more.
Rajini Rao I think that’s more Allison Sekuler area but if I recall correctly, the region they are talking about thins naturally with age, kind of like my hair. The superagers are analogously not follically challenged.
LOL, Chad Haney ! Don’t forget that the bard said, “There’s many a man that hath more hair than wit” 🙂
I’ll trade my wit for hair.
No way. Hair is overrated anyway 🙂
Touché or toupée?
no longitudinal studies yet – the field is so young!
Definitely not to toupée. I’ll shave my head first.
BTW, Allison Sekuler if your colleagues ever want to try spectroscopic imaging (EPSI) instead of BOLD, I’d be happy to point them in the right direction.
do you mean like MRS?
No MRS usually implies localized spectroscopy. I’m talking about high spatial and spectral resolution MRI (4D), developed by my boss. Also, so far we don’t look at other nuclei, just protons.
interesting. I’ll check with my physics collaborator and others 😉
I was reading about this Chad Haney, the works sounds awesome. Have they done some tests to figure out what makes some brains superagers? I was reading this on this article and your post makes it quite clear… http://esciencenews.com/articles/2012/08/16/secrets.superager.brains
I don’t think they know yet, Lacerant Plainer
Gotcha, okay just been bugging me lol – thanks Chad Haney 🙂
As Allison Sekuler mentioned, it’s early days.
If we don’t have good data, we will make it up? Eww.
Jyoti Dahiya what are you referring to?
If the voxel is bigger than the difference they saw…
That’s what I thought you were commenting on. They aren’t radiologist or imaging people. I think they misunderstood what the software can do in general vs. with the data they have. Again, I’m making assumptions because they didn’t report all of their parameters.
Le sigh on not reporting all the parameters.