This is an alternative head for Alsamen’s “Nixon Bender Suit” https://www.thingiverse.com/thing:4539807

When I first saw Alsamen’s design I looked at my brain on my desk (the 3D one I printed) and thought: I must do it! The top cover contains an LED and a CR2032 battery. The best is to use the guts of a tea lamp LED (https://www.google.ca/search?q=led+tea+light). No soldering required and the blinking effect add a spooky look! Note how I bent away from each other the LED’s leads (see photo). A small flat screwdriver works great to bend the leads. There is no ON-OFF switch: simply push or pull the battery in the slot.
The brain is glued to the base with a drop of hot melting glue for a shorter setting time. Like Alsamen’s design you need a cutout of a soda bottle or another plastic to complete the head. For this design, the dimension is 50mm x 135mm.

Brain
Layer height: 0.12
Support: touching build plate only
Careful: the stem is easy to break. I broke mine so I used a piece of copper wire as a reinforcement before gluing it back.

Base
Layer height: 0.2
Support: none

Top cover
Layer height: 0.2
Support: everywhere. Tip: increase the support Z distance by 0.05mm for an easier removal.

Eyes & mouth
Layer height: 0.12
Support: none
No brim required
The eyes have a flat side as the iris/pupil. This make them easier to print and color with a fine tipped sharpie. The right eye does not fully enter the brain. Sorry, my brain is asymmetrical!
You have two choices for the mouth: with or without cigar. Use a BIG sharpie to darken the edges of the mouth. Do not use a small one: you will stain the teeth. See picture.

Lenses
Layer height: 0.24
Support: none
Infill: 100%
I have tried to cut it in 2 halves and print them vertically to get a better light diffusion. Does not worth it. Tip: some transparent filaments are clearer at a higher temperature. Test your own!

Cigar
Layer height: 0.2
Support: none
No brim required