Expression of combinations of three different fluorescent proteins in a mouse brain produced ten different colored neurons. Individual neurons in a mouse brain appear in different colors in a fluorescence microscope. This “Brainbow” method enables many distinct cells within a brain circuit to be viewed at one time.
Understanding how the brain’s complex map of neural connections actually works is one of the greatest challenges faced by scientists today, but new research by the University of New South Wales (UNSW) provides greater insight into how our brainwaves function when resting, and it could have huge implications for our understanding the brain’s vast ’connectome’.
“It has been a mystery why these spontaneous patterns of brain activity occur when people are simply lying in a brain scanner not thinking about anything in particular and not doing any explicit task,” said one of the researchers, psychologist Joel Pearson.
Pearson and his team created three-dimensional maps of the structures of 10 patients’ brains using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) techniques. “The MRI gave us the structure of their cortex - the wrinkly surface of the brain - and the DTI gave us an anatomical map of the underlying connections of the white matter in the brain,” he says.
The incidence of HIV-associated dementia has declined dramatically since the introduction of potent combined antiretroviral therapy; however, milder forms of HIV-associated neurocognitive disorders (HAND) persist. Some 30 to 50 % of HIV-infected individuals have HAND. With an increasing proportion of HIV-infected individuals at risk of HAND, the development of a treatment and mapping of…
1. Apparently brains can look really different:
“This is because, although gross neuroanatomical features are generally
conserved across people, there can be a huge range of variation. For
example, in the frontal lobes, there are usually three longitudinal
gyri: inferior, middle, and superior: I’ve seen people with a whole extra fourth gyrus just stuck right in there. Totally surprising! What is that?!“
4. The same article notes: “This doesn’t make dolphins necessarily more intelligent than us though
as there are other factors to consider; such as the fact that dolphins
have a relatively thinner surface of their brain“.
Which may be another great way to pose the question I’m having: Why not have a thinner cortex with even more folds?
There are several theories about how the brain’s folds form. These
include the possibility that more neurons migrate to the hills, making
them rise above the valleys, or that the valleys are pulled down by the
axons – fibres that connect neurons to each other – linking highly
interconnected parts of the brain together. Mahadevan’s model shows that, as long as the cortex is attached to
the white matter beneath, the only thing needed is expansion of the
cortex, and it will physically buckle. “Once you have that, everything
else follows,” says Mahadevan. “It’s an extremely simple mechanism.”
The NYT similarly asserts that “Human intelligence appears to be related to the branching of brain cells
and the formation of complex links between them, not the shape of the
platform where the links take place.“
Most animals have smooth brains. The brains of humans (and a handful of animals we consider pretty intelligent – dolphins, chimps, elephants, pigs) start out smooth in the early days of gestation and get more and more wrinkled through infancy.
A wrinkled brain makes sense - folding means you can have a really big cortex but the different parts of the brain won’t be as far apart. But how do brains become wrinkled? Is it programmed somehow - does some genetic code determine the pattern of folds?
A new study from Harvard says no - its just simple physics. They created a 3D model of a smooth fetal brain and coated it with an elastomer gel “cortex.” When they immersed this brain in a special solution, the gel swelled, mimicking brain growth.
Lo and behold, the brain began to buckle, creating folds similar to size, shape and location of a real brain.
Since I get asked a lot about where to learn more about the human brain and behaviour, I’ve made a masterpost of books, websites, videos and online courses to introduce yourself to that piece of matter that sits between your ears.
The Brain Book by Rita Carter
The Pyschology Book (a good starter book) by DK
Thinking, Fast and Slow by Daniel Kahneman
Quiet: The Power of Introverts in a World That Can’t Stop Talking by Susan Cain
The Man Who Mistook His Wife for a Hat by Oliver Sacks
The Brain: The Story of You by David Eagleman
The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge
This Is Your Brain on Music by Daniel Levitin
The Autistic Brain
by Richard Panek and Temple Grandin
Sapiens: A Brief History of Humankind by Yuval Noah Harari (not really brain-related, but it is single handedly the best book I have ever read)