But donors are letting researchers at the Allen Institute for Brain Science in Seattle keep chunks of their brains for experiments. The Frankenstein-esque process allows experts to study the cells while they are still connected and buzzing with electrical impulses.
Findings presented at the American Association for the Advancement of Science conference in Seattle today suggested this was a far more accurate base for experiments than rodent models.
Lead researcher Professor Ed Lein said: “More and more we are appreciating that we need to understand the cellular and circuit architecture if we are to have a hope of curing diseases of the brain.
“Normally brain tissue is treated as medical waste.
“Instead we are treating it as an opportunity to understand the cells and circuitry.”
Most of what we know about the human brain comes from studying tissue donated after death and brain scanning technology.
Scientists also often turn to animal models, but Prof Lein said “there’s only so much one can do” with mice and rats.
He said: “Now we have access to these types of properties we can see really significant differences between the organisation of the human cortex and the mouse.”
The surgical donation programme began five years ago, with findings beginning to trickle in in recent months.
There has been an “incredible response” to the research, Prof Lein said, with most patients approached about donation “very willing” to consent. Around 50 agree to let doctors keep samples of their brains every year.
He added: “For the most part patients understand that while they are in a personally tragic situation, they can do something good that doesn’t impact the outcome of their surgery.
“The brain is a privileged organ. That piece of brain was participating in that person’s thoughts not long before.
“That makes this work a lot more meaningful. We are studying an intimate piece of personality at some level.”