www.lesswrong.com/posts/BAmPQWsmvBmwdwgWd/does-preservation-make-sense-before-we...

This sentence conflates total CSF volume with ventricular volume.

Authoritative references describe adult CSF volume as about 150 mL total, with only about 25 mL in the ventricles:

• StatPearls: "In adults, total CSF volume measures approximately 150 ml—about 125 ml within the subarachnoid spaces and 25 ml within the ventricles."
• Physiological Reviews: "The ventricles in healthy young adults have a volume of ∼25 mL, representing <20% of total CSF volume (130–150 mL)."

So saying the ventricles contain "around 200 ml" is not a small rounding issue; it overstates normal ventricular volume by roughly an order of magnitude.

The cited paper says something importantly different from what the article claims.

Huebinger et al. measured how long aldehyde fixation takes to stop cytosolic protein movement. Their abstract states that fixation times "greatly vary from less than 4 to more than 60 minutes, depending on the aldehydes used." In the results, they report that 2% glutaraldehyde fixed cytoplasmic proteins within 4 minutes.

So the paper does not show that after "around 60 seconds" the cytoplasm has already formed a gel that traps essentially all proteins, DNA, lipids, etc. If anything, it emphasizes that fixation proceeds on the timescale of minutes, not one minute, and also notes lipid blebbing and redistribution artifacts during aldehyde fixation.

This is too absolute. White matter does change with learning.

A major review in Nature Neuroscience states plainly that "Human brain imaging has identified structural changes in gray and white matter that occur with learning." The same review summarizes training-related white-matter changes in adults.

Likewise, a review on adaptive myelination explains that CNS myelin is "dynamically regulated throughout development and life" and that neuronal activity can regulate myelination itself. Because white matter is largely made of long-range axons plus their myelin and supporting glia, these findings directly contradict the claim that the long-range white-matter connections do not change in response to learning.

This caption mixes up ECG (electrocardiogram, heart electrical activity) with EEG (electroencephalogram, brain electrical activity).

The cited paper is titled "Deep hypothermic circulatory arrest: I. Effects of cooling on electroencephalogram and evoked potentials" and its abstract discusses EEG burst suppression and electrocerebral silence during cooling. So the traces in this context are EEG traces, not ECG.

Stecker et al. measured electroencephalogram (EEG) changes during cooling for deep hypothermic circulatory arrest. Their results do not support a fixed threshold where brain activity "stops completely" at around 16°C.

What they actually reported:

• Mean temperature for electrocerebral silence was 17.8°C ± 4°C.
• Only 60% of patients reached electrocerebral silence by 18°C or 30 minutes of cooling.
• The authors concluded that the only absolute predictors of electrocerebral silence were cooling below 12.5°C or longer than 50 minutes.

So the paper itself shows that complete EEG silence is variable and is not reliably achieved just because a patient has been cooled to about 16°C.