Benjamin Kay

Poor image quality introduces systematic bias into MRI data Analyses that include low-quality MRI data underestimate cortical thickness and overestimate surface area, according to new work from the ABCD Study.

Poor image quality introduces systematic bias into large neuroimaging datasets, new study of ABCD data shows.

By Natalia Mesa

www.thetransmitter.org/spectrum/poo...

Excited to see the latest paper from @bttyeo.bsky.social's lab finally published in Nature! Now I know the most economical way to spend my grant money on MRI! No surprise, sample size matters, but adequate sampling in scan time can reduce the cost of sampling adequate numbers of participants.

Once again, if you give @gordonneuro.bsky.social et al a network, they're going to want to characterize its subnetworks... A thought provoking read on the AMN (née CON) and the brain architecture of the decision-action-feedback loop. I always feel smarter after reading these kinds of papers!

Fantastic work from @drdamienfair.bsky.social's using the latest in precision neuroimaging and neuromodulation to untangle the mechanisms of chronic pain!

That's an intriguing question! We analyzed data from the ABCD n-back task as if it were rest and found essentially the same stimulant-related differences in FC as we did for "pure" rest, see Supplemental Figure 4.

Touché... although I've never once had a program officer tell me that I've been publishing too much 😅

I appreciate your offer of help! We're always looking for ways to extract the most quality out of our precision studies, so I may need to take you up on that at some point!

This is not meant to be directed at @ckorponay.bsky.social, but I take issue with reviewers in general asking for large data sets to be reprocessed using their favorite pipeline without strong theoretical justification. Reprocessing 40,000+ scans takes a lot of taxpayer $$$!

Let's suppose, for the sake of argument, that our stimulant-related differences in FC are due entirely to decreased sLFO inflation in children taking stimulants. If sLFO inflation is driven by diminishing arousal, this would still support our central hypothesis that stimulants increase arousal.

Snark aside, we've appreciated non-stationarity of fMRI BOLD going back to the early days of Friston and Volterra kernels. Every denoising pipeline has grappled with this to some extent, and I'm excited to see the insights from @ckorponay.bsky.social's RIPTiDe get incorporated into future pipelines.

We're confident stimulants modulate arousal, but how much of what we see is "pure" neuronal signal and how much is filtered through physiology is an open question for all fMRI studies. It's terrific having tools like RIPTiDe, and your paper raises awareness about collecting physiological covariates!

Global waves synchronize the brain’s functional systems with fluctuating arousal Traveling waves spatiotemporally organize brain-wide activity in synchrony with ongoing arousal fluctuations.

Yes, loved the fresh perspective of your Nat Hum Behav article, more and more we're realizing how much arousal and associated physiological changes affect rs-fMRI. I'm sure you know Ryan Raut's work doi.org/10.1126/scia... and Catie Chang's recent Nat Neurosci paper doi.org/10.1038/s415...

Renewal of NIH grants linked to more innovative results, study finds Survey of hundreds of scientists’ work suggests that cutting off funding disrupts focus and reduces the novelty of research.

It's not surprising to see that cutting off funding disrupts science and impacts its novelty, but I think it's important that this is documented and shared 🧪 . For more see the news coverage in @nature.com www.nature.com/articles/d41...

That's a really interesting hypothesis! We think norepinephrine drives the arousal boost and dopamine drives the salience boost. Whether high levels of dopamine cause psychosis through the salience network or through other brain targets is an open question, see Winton-Brown: doi.org/10.1016/j.ti...

This is the point of our story: the biggest differences in connectivity are in arousal and salience networks (to which PMN is closely yoked). Contrary to what people expect, the differences in "top down" attention networks are relatively smaller (FPN) or basically not existent (DAN).

You are reading those matrices correctly! The decreased within-network FC in primary systems is what we see in subjects who are more alert/better rested. The between-network differences are significant for SAL and PMN. There may be a trend for DMN and FPN, but it didn't reach significance.

You're right, the link between amphetamines and sleep dates back to Gordon Alles 1927. The link with salience goes back to at least Robbins (Nature) 1976. That hasn't stopped claims that MPH acts directly on attention. Our study shows the greatest effects are on arousal and salience, not attention.

Yes, we've long argued that there are both "top-down" and "bottom-up" attention systems. The novelty here is showing that stimulants act primarily on "bottom-up" attention.

Agree, don't assume the labels we've given networks reflect their functions! (See @ndosenbach.bsky.social's perspective on the brain from inside out: doi.org/10.1038/s415...) It seems the brain's arousal and salience systems play a larger role in facilitating attention than was first appreciated...

That's a good insight, and we try to make the point that salience has a strong, facilitatory role in attention. We still think it's remarkable not to find *any* difference in the functional connectivity of dorsal attention network and frontoparietal network, the "classical" attention networks.

Totally agree! See, for example, ‪@biyuhe.bsky.social‬ and her excellent work on arousal and perception. It makes sense that the brain would also have a mechanism for redirecting attention toward goal-oriented actions with the greatest anticipated reward. Stimulants seem to tap into both systems!

Stimulants helped children with ADHD or insufficient sleep do better on cognitive tasks. They seem to mask the effects of fatigue and elevate the perceived salience of goal-oriented actions, helping you do tasks you find boring without directly affecting your capacity to pay attention.

Stimulants also increased connectivity of salience network, which encodes anticipated reward, influencing motivation and task-switching. We hypothesize stimulants elevate the perceived salience of mundane tasks (e.g. schoolwork), facilitating attention without directly acting on attention networks.

The arousal-related differences in connectivity associated with stimulants were so strong that they completely negated brain differences related to not getting enough sleep!

Arousal is associated with decreased connectivity in somatomotor networks – exactly the pattern we see in children taking stimulants. The stimulant pattern is highly similar to EEG- and physiologically-derived maps of arousal and concordant with norepinephrine density.

We were so surprised, we replicated our findings in a precision imaging drug trial of healthy adults taking an experimentally controlled dose of Ritalin (methylphenidate). The stimulant trial brain maps were highly correlated with those from ABCD p < 0.001.

My med school textbook says stimulants like Ritalin treat hyperactivity by “stimulating” the brain’s attention and cognitive control systems. We studied children taking stimulants in the ABCD Study, and the largest differences were actually in arousal and reward networks! Check out our preprint!

Had a great time speaking with Sydney about our most recent paper out now in @natcomms.nature.com @macwoodburn.bsky.social . Paper link here: rdcu.be/ehbOy

‘Old’ brainstem structure evolved beyond basic motor control The human red nucleus may also help coordinate action, reward and motivated behavior, a new study suggests.

The brainstem’s red nucleus is an evolutionarily old structure that emerged as animals began to use limbs for walking, but its function in humans reaches beyond motor control, a new study suggests.

By @sydneywyatt.bsky.social

#neuroskyence

www.thetransmitter.org/brain-imagin...

It turns out the brain🧠is silently🤫working when your arm is in a cast. 🩼 🚧
Plastic changes occur, and revert again when the cast is removed … not just in cortex.