In case anyone else is interested (or as geeky as I am). Here is a very simple protocol for making a paperweight (etc) with an extra brain that is not going to be used for research. I will upload some pictures so that you can see what they look like when they are finished.

Materials: brain, 100% ethanol, clear casting resin and hardener (available at most hardware stores), mold (can be any shape you like or you could make your own – I used plastic rectangular molds used for paraffin embedding), sandpaper or grinding wheel, polishing wheel, polishing compound.

1. Place brain in 100% ethanol. You may have to do this several times as it is very important to remove all traces of water from brain. Excess water causes “silvering” which simply means that you get a sliver discoloration on the brain.

2. Briefly dry the brain under a low heat lamp.

3. Fill the mold halfway with the clear casting resin (with the hardener already added) and remove any bubbles with a pin. Need to position the brain quickly before it hardens too much. The small fish brains floated for the most part so it was relatively easy. Ideally you want half the brain in the plastic and half outside the plastic. This is because the hardening of the clear casting resin is an exothermic reaction and it will help evaporate any residual water from the brain.

4. When the bottom layer of resin becomes slightly tacky pour the top layer of clear casting resin (with the hardener already added) on top of it. If you pour the resin too soon it will cause the brain to shift positions, too late and you get a line through the block that clearly distinguishes the two layers.

5. Let harden for 1-2 days.

6. Use sandpaper or a grinding stone to remove the thin outer layer which remains tacky. You can get very creative if you are so inclined.
7. Polish. I use the polishing wheel on a Dremel and an Alumina Slurry. First I use 0.3 micron (#50368-20) and then 0.05 micron (#50368-10) Alumina slurry from Electron Microscopy Sciences. However, there are multiple ways to achieve the same end result.

I have made a small collection of fish brains preserved in this manner that I show people when they visit the lab and I talk about my research. I always point out the differences in the cerebellum. Even in these pictures, which aren't great, the cerebellum of the butterflyfish (in red) point straight up, the cerebellum of the surgeonfish (in yellow) overlies the top of the tectum, and the cerebellum of the wrasses (in blue) are very different from one another. My favorite is Novalichthys taeniourus (the rock mover wrasse) whose cerebellum is shaped like a "T".

Please post or contact me if you have any questions.

Small paperweights made from clearcasting resin with various fish brains.

A piece of jewelry with a butterflyfish brain inside that a guy from the Hawaii Institute of Marine Biology shop made. My wife actually wears this piece of jewelry from time to time.

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Comment by nikhil palande on November 9, 2009 at 9:12pm
Comment by Sabrina Burmeister on November 8, 2009 at 3:16pm
Very cool!

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