Around one billion people suffer from neurological disorders like Alzheimers and Parkinsons, and researchers around the are world looking for cures and ways of prevention.
Recently, they've started growing simplified versions of human brain tissue in labs.
One such lab is the Brain Bank, where the brain tissue of around 800 donors is stored at Auckland University.
Sir Richard Faull, the director for the Centre for Brain Research at Auckland University, says the donated brain tissue is making a huge difference because "that’s the brain we want to cure".
"These brains are gifted to us by families when they die of Alzheimers, Huntingtons, Parkinsons, epilepsy, motorneuron disease. They are the most valuable gift you can ever give to research," Sir Faull said.
Mike Dragunow, an Auckland University professor and neuroscientist, says studying human brain cells is "the best way possible moving forward".
"We're using the cells to study the disease and then using the cells to test drugs that may treat the diseases," Mr Dragunow said.
The world-leading research has managed to slow the spread of brain tumour cells in the lab, as well as discovering that the brain can not only repair its cells, it can also generate new ones.
"When you see people in families with Alzheimers, motorneuron disease, epilepsy, brain tumours, you understand there is a pressing need.
"It's our duty to try and do something about that."
Overseas, they're taking it even further, growing brain tissue from stem cells.
These "brain organoids" are in their infancy.
Hank Greely, a Stanford University law professor specialising in the ethical, legal and social issues rising from advancements in biosciences, believes in the future, we will be able to create "big organoids large enough to make us nervous probably at some point".
"They’re about 6 million neurons, but human brains have 89 billion neurons, so six million is pretty small," Mr Greely said.
"We don't understand consciousness at all, but we understand them enough to know they’re too small to be conscious. Multiply that by 100 times and it gets trickier."
Mr Greely, along with researchers from universities like Duke, Standford, Harvard and Yale gathered to talk about ethics as the world gets closer to creating a functional human brain.
"The big question is what's going on inside that thing? Is there a human consciousness? If it's complicated enough to feel pain, that would be worrisome. The real tricky thing is how do we tell?"
Mr Greely says research is accelerating, so guidelines should be put in place.
"If we were to take some skin cells from you and me and turn them into organioids, should we tell you what we're going to do with them?
"Already, the work was beginning to raise eyebrows and cause us to wonder where we are going."
Scientists in the country are unsure whether we will ever create a working brain, but are certain people will try.