Research: Everyone has Unique Brain Anatomy

Apparently this wasn’t thought much 30 years ago. It is also a bit surprising that some of the differences are driven primarily by repeated experiences.

Like with fingerprints, no two people have the same brain anatomy, a study by researchers of the University of Zurich has shown. This uniqueness is the result of a combination of genetic factors and individual life experiences.

The fingerprint is unique in every individual: As no two fingerprints are the same, they have become the go-to method of identity verification for police, immigration authorities and smartphone producers alike. But what about the central switchboard inside our heads? Is it possible to find out who a brain belongs to from certain anatomical features? This is the question posed by the group working with Lutz Jäncke, UZH professor of neuropsychology. In earlier studies, Jäncke had already been able to demonstrate that individual experiences and life circumstances influence the anatomy of the brain.

Experiences make their mark on the brain

Professional musicians, golfers or chess players, for example, have particular characteristics in the regions of the brain which they use the most for their skilled activity. However, events of shorter duration can also leave behind traces in the brain: If, for example, the right arm is kept still for two weeks, the thickness of the brain’s cortex in the areas responsible for controlling the immobilized arm is reduced. “We suspected that those experiences having an effect on the brain interact with the genetic make-up so that over the course of years every person develops a completely individual brain anatomy,” explains Jäncke.

Magnetic resonance imaging provides basis for calculations

To investigate their hypothesis, Jäncke and his research team examined the brains of nearly 200 healthy older people using magnetic resonance imaging three times over a period of two years. Over 450 brain anatomical features were assessed, including very general ones such as total volume of the brain, thickness of the cortex, and volumes of grey and white matter. For each of the 191 people, the researchers were able to identify an individual combination of specific brain anatomical characteristics, whereby the identification accuracy, even for the very general brain anatomical characteristics, was over 90 percent.

Combination of circumstances and genetics

“With our study we were able to confirm that the structure of people’s brains is very individual,” says Lutz Jäncke on the findings. “The combination of genetic and non-genetic influences clearly affects not only the functioning of the brain, but also its anatomy.” The replacement of fingerprint sensors with MRI scans in the future is unlikely, however. MRIs are too expensive and time-consuming in comparison to the proven and simple method of taking fingerprints.

Progress in neuroscience

An important aspect of the study’s findings for Jäncke is that they reflect the great developments made in the field in recent years: “Just 30 years ago we thought that the human brain had few or no individual characteristics. Personal identification through brain anatomical characteristics was unimaginable.”

Almost 1000 New Genes Related to Intelligence Found

The deeper understanding of intelligence allows for it to be recreated, utilized and optimized more effectively. There are certainly more than enough problems in the world — more intelligence could be very helpful in solving them.

Researchers have identified over 1,016 specific genes associated with intelligence, the vast majority of which are unknown to science.

An international team conducted a large-scale genetic association study of intelligence and discovered 190 new genomic loci and 939 new genes linked with intelligence, significantly expanding our understanding of the genetic bases of cognitive function.

Led by statistical geneticist Danielle Posthuma from Vrije Universiteit Amsterdam in the Netherlands, the researchers performed a genome-wide association study (GWAS) of almost 270,000 people from 14 independent cohorts of European ancestry.

All these people took part in neurocognitive tests that measured their intelligence, and when researchers contrast their scores with variations in the participants’ DNA – called single nucleotide polymorphisms (SNPs) – you can see which mutations are associated with high intelligence.

From over 9 million mutations detected in the sample, Posthuma’s team identified 205 regions in DNA code linked with intelligence (only 15 of which had been isolated before), and 1,016 specific genes (77 of which had already been discovered).

According to the team, the genes that make for smartness also look to confer a protective effect to overall cognitive health, with the analysis finding a negative correlation with Alzheimer’s disease, attention deficit/hyperactivity disorder, depressive symptoms, and schizophrenia.

The intelligence genes were however correlated with increased instances of autism, and also longevity, suggesting people with these genetic underpinnings of high intelligence are more likely to live longer.

“Our results indicate overlap in the genetic processes involved in both cognitive functioning and neurological and psychiatric traits and provide suggestive evidence of causal associations that may drive these correlations,” the researchers write.

“These results are important for understanding the biological underpinnings of cognitive functioning and contribute to understanding of related neurological and psychiatric disorders.”

Study: Leg Exercise is Crucial to Brain and Nervous System Health

The relation between having both a strong mind and body is shown again, this time with reasoning as to why leg day shouldn’t be skipped at the gym.

Groundbreaking research shows that neurological health depends as much on signals sent by the body’s large, leg muscles to the brain as it does on directives from the brain to the muscles. Published today in Frontiers in Neuroscience, the study fundamentally alters brain and nervous system medicine — giving doctors new clues as to why patients with motor neuron disease, multiple sclerosis, spinal muscular atrophy and other neurological diseases often rapidly decline when their movement becomes limited.

“Our study supports the notion that people who are unable to do load-bearing exercises — such as patients who are bed-ridden, or even astronauts on extended travel — not only lose muscle mass, but their body chemistry is altered at the cellular level and even their nervous system is adversely impacted,” says Dr. Raffaella Adami from the Università degli Studi di Milano, Italy.

The study involved restricting mice from using their hind legs, but not their front legs, over a period of 28 days. The mice continued to eat and groom normally and did not exhibit stress. At the end of the trial, the researchers examined an area of the brain called the sub-ventricular zone, which in many mammals has the role of maintaining nerve cell health. It is also the area where neural stem cells produce new neurons.

Limiting physical activity decreased the number of neural stem cells by 70 percent compared to a control group of mice, which were allowed to roam. Furthermore, both neurons and oligodendrocytes — specialized cells that support and insulate nerve cells — didn’t fully mature when exercise was severely reduced.

The research shows that using the legs, particularly in weight-bearing exercise, sends signals to the brain that are vital for the production of healthy neural cells, essential for the brain and nervous system. Cutting back on exercise makes it difficult for the body to produce new nerve cells — some of the very building blocks that allow us to handle stress and adapt to challenge in our lives.

“It is no accident that we are meant to be active: to walk, run, crouch to sit, and use our leg muscles to lift things,” says Adami. “Neurological health is not a one-way street with the brain telling the muscles ‘lift,’ ‘walk,’ and so on.”

The researchers gained more insight by analyzing individual cells. They found that restricting exercise lowers the amount of oxygen in the body, which creates an anaerobic environment and alters metabolism. Reducing exercise also seems to impact two genes, one of which, CDK5Rap1, is very important for the health of mitochondria — the cellular powerhouse that releases energy the body can then use. This represents another feedback loop.

These results shed light on several important health issues, ranging from concerns about cardio-vascular impacts as a result of sedentary lifestyles to insight into devastating diseases, such as spinal muscular atrophy (SMA), multiple sclerosis, and motor neuron disease, among others.

Memory Transferred Through Snails Using RNA Injection

Memory is one of the most important aspects of creatures with higher intelligence, and it was recently found that animals can mentally replay past events. Altering the processes that control memory could be enormously useful — as in restoring positive memories — or enormously harmful — as in deleting memories of events that were vital to learning. That’s technology’s lack of a moral imperative though — the outcome depends on how it’s used.

UCLA biologists report they have transferred a memory from one marine snail to another, creating an artificial memory, by injecting RNA from one to another. This research could lead to new ways to lessen the trauma of painful memories with RNA and to restore lost memories.

“I think in the not-too-distant future, we could potentially use RNA to ameliorate the effects of Alzheimer’s disease or post-traumatic stress disorder,” said David Glanzman, senior author of the study and a UCLA professor of integrative biology and physiology and of neurobiology. The team’s research is published May 14 in eNeuro, the online journal of the Society for Neuroscience.

RNA, or ribonucleic acid, has been widely known as a cellular messenger that makes proteins and carries out DNA’s instructions to other parts of the cell. It is now understood to have other important functions besides protein coding, including regulation of a variety of cellular processes involved in development and disease.

The researchers gave mild electric shocks to the tails of a species of marine snail called Aplysia. The snails received five tail shocks, one every 20 minutes, and then five more 24 hours later. The shocks enhance the snail’s defensive withdrawal reflex, a response it displays for protection from potential harm. When the researchers subsequently tapped the snails, they found those that had been given the shocks displayed a defensive contraction that lasted an average of 50 seconds, a simple type of learning known as “sensitization.” Those that had not been given the shocks contracted for only about one second.

The life scientists extracted RNA from the nervous systems of marine snails that received the tail shocks the day after the second series of shocks, and also from marine snails that did not receive any shocks. Then the RNA from the first (sensitized) group was injected into seven marine snails that had not received any shocks, and the RNA from the second group was injected into a control group of seven other snails that also had not received any shocks.

Remarkably, the scientists found that the seven that received the RNA from snails that were given the shocks behaved as if they themselves had received the tail shocks: They displayed a defensive contraction that lasted an average of about 40 seconds.

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Scientists know more about the cell biology of this simple form of learning in this animal than any other form of learning in any other organism, Glanzman said. The cellular and molecular processes seem to be very similar between the marine snail and humans, even though the snail has about 20,000 neurons in its central nervous system and humans are thought to have about 100 billion.

In the future, Glanzman said, it is possible that RNA can be used to awaken and restore memories that have gone dormant in the early stages of Alzheimer’s disease. He and his colleagues published research in the journal eLife in 2014 indicating that lost memories can be restored.