A form of brain abnormality long regarded as permanent is, in fact, sometimes reversible, according to an unassuming little paper with big implications.
Here’s the key data: some rats were given a lot of alcohol for four days (the “binge”), and then allowed to sober up for a week. Before, during and after their rodent Spring Break, they had brain scans. And these revealed something remarkable – the size of the rats’ lateral ventricles increased during the binge, but later returned to normal.
Control rats, given lots of sugar instead of alcohol, did not show these changes.
This is really pretty surprising. The ventricles are simply fluid-filled holes in the brain. Increased ventricular size is generally regarded as a sign that the brain is shrinking – less brain, bigger holes – and if the brain is shrinking that must be because cells are dying or at least getting smaller. So bigger ventricles is bad.
Or so we thought… but this study shows that it might not always be true: alcohol reversibly increases ventricular volume over a timescale of days. It does so, the authors say, essentially by drying brain tissue out; like most things, if you dry the brain out, it gets smaller (and the ventricles get bigger) but when the water comes back to the tissues, it expands again.
As you can see here in Figure 2…
Maybe. I admit that just eyeballing this, it looks more like the ventricles are getting brighter, rather than bigger, but I’m not familiar with the details of water scanning. Maybe some readers will know more about it.
If it’s true, this is big – maybe it’s not just high doses of alcohol that does this. Maybe other drugs or factors can shrink or expand, the ventricles, or even other areas, purely by acting on tissue water regulation, rather than by anything more ‘interesting’.
Of course, this is in mice – and it might not translate to humans… we need to find out, and I for one am keen to apply for a grant. Here’s my draft:
Participants: 8 healthy-livered neuroscientists.
Materials: 1 MRI scanner, 1 crate Jack Daniels.
Methods: Subjects will confer to pick a Designated Operator, who will remain sober. If no volunteers for this role are forthcoming, selection will be randomized by Bottle Spinning. All other participants will consume Jack Daniels ad libitum, and take turns being scanned. Once all Jack Daniels is depleted, participants will continue to be scanned until fully sobered up (defined as when they can successfully spell “amygdalohippocampal”).
Instructions to Participants: i) what happens in the magnet, stays in the magnet. ii) If you ‘dirty’ the scanner, you clean it up. iii) Bottle caps are not MRI safe!
Er… seriously though, someone should check.
Zahr NM, Mayer D, Rohlfing T, Orduna J, Luong R, Sullivan EV, and Pfefferbaum A (2013). A mechanism of rapidly reversible cerebral ventricular enlargement independent of tissue atrophy. Neuropsychopharmacology PMID: 23306181