Tag Archives: brain

Mothers Carry Pieces of their Children—In Their Brain

Did you know that long after you’re born, your mother carries little parts of you in her body? This phenomenon is called ‘microchimerism’, the presence of foreign cells in a tissue or organ. Recent research has now found cells from the foetus in the most distal part of the mother’s body, the head.

Babies’ Cells Migrate Into Mothers’ Bodies

Microchimerism arises during pregnancy when fetal cells move into the mother’s body where they may persist and multiply for a long time. This phenomenon is how the complete sequence of a foetus’s DNA can be determined simply from the mother’s blood. The effects of these cells on the mother’s health, if any, aren’t known. Some hypothesize that these ‘foreign’ cells could trigger off the mother’s immune system leading to autoimmune diseases. Others hypothesize that these cells actually help in the repair of damaged tissues in the maternal body. The kidneys, lungs, liver, lymph nodes and the hearts of mothers have been found to contain their sons’ DNA. Do they also travel to the brain?

fetal DNA in mother's brain
The origins of microchimerism. It is during pregnancy that cells from the foetus enter the mother’s body and may persist for as long as a few decades. [Image Credit: Wikimedia commons]

Looking for Y Chromosomes in Female Brains

Firstly, let’s talk about why ‘son’s’ DNA is mentioned, but not daughters’ DNA lest scientists be accused of sexism. Males contain a copy of the Y chromosome while females don’t. Merely finding a piece of this chromosome in a woman would be sufficient to determine the presence of foreign cells (most likely to be her son’s). On the other hand, to look for a daughter’s DNA, scientist would have to look for very specific differences between the mother and the daughter’s genes.

Keeping this in mind, researchers at the University of Washington in Seattle tested if a particular sequence of DNA in the Y chromosome was found in the brains of women who had sons. 63% of mothers were found to contain this segment of DNA, indicating that fetal cells do, in fact, travel all the way to the brain.

The next time your mother says you’re in her heart or on her mind, you know she means it literally. You can read about this research here.

Good at Maths? Your Brain Communicates Better

Have you ever wondered why you are decent at Mathematics? Well, it isn’t just because of wonderful Mrs. Gunderson who taught you in high school. It’s because certain parts of your brains have more ‘wires’, or neurons, connecting them.

Division of Labor—Recognizing Quantities and Computing Are Done by Two Different Halves

There is a region of the brain called the parietal cortex  that performs the role of numerical cognition. Additionally the left and the right halves of this cortex perform different parts of this activity. While the right parietal cortex primarily processes quantities, i.e. this half confers an intuitive sense of the magnitudes of numbers and their relationships, the left half performs numerical operations. What has remained unknown is how these two halves work together while we perform arithmetic that requires the functions of both halves.

The parietal cortex is the outer art of the parietal lobe. [Image Credit: thebrain.mcgill.ca]

Greater Neural Crosstalk Improves Arithmetic Ability

Researchers at the University of Texas and the University of Michigan used functional MRI to image the brains of 27 adults and found that the neural connectivity between the left and the right parietal cortex increased in each of these individuals when they were given mathematical problems to solve. Individual participants who were faster at performing the arithmetic tasks (subtraction in this case) were found to have greater connectivity between the two halves, whereas no such correlation was found between speed of computing and activity within each half. This implies that the speed at which we compute depends to some extent on how fast numerical quantities and operations transmit between the two halves of the cortex.

Before some of us rush to place the blame for our mathematics grades on our genes, it should be noted that the brain is remarkably plastic. The more we work on something, the better the brain becomes at it. The neural structure of our brains might be a result of extensive mathematics practice rather than inherited. This study therefore reflects the mechanism, and not the cause of arithmetic ability. Thus, you might just have to thank Mrs. Gunderson for your enhanced neuronal structure after all.

You can read about this research here.

Another Reason to Hit the Sack— Humans Can Learn While Asleep

Sleep is a state of being characterized by a lack of consciousness. But are we capable to perceiving sensory stimuli while we are asleep, or we totally oblivious to the world around us? It is known that humans can strengthen previously acquired memories during sleep, but it is not known if we can actually take in new information.

If a Skunk Passes By While We Sleep, Would Our Brain Know It?

Researchers at the University of Israel decided to test the assimilation and acquisition of new non-verbal information during sleep. It is known that we respond to unpleasant smells by producing shorter sniffs, and to pleasant smells by longer, deeper sniffs. The research team used this information to create a unique test. While participants were asleep, they paired odors with musical tones, i.e., an odor-tone pairing was created with the tone being separated by the odor by at least 1 second. To ensure that these were being detected by the participants, their sniffing behavior was studied, and it was ensured that their sniffs were shorter when unpleasant odors were being presented. They also ensured that participants did not wake up in response to these odors; participants who did wake up within 30 minutes of the experiment were excluded from the analysis.

Sleeping might be less wasteful that you thought. [Image Credit: wikipedia]

Upon waking up, the same participants were presented to the tones alone, and it was found that the tones which were paired with unpleasant odors induced a shorter sniffing response in the participants. Moreover, they were unaware of the experiments that had been conducted while they were asleep. This shows that their brains could process at least two things—odor processing, and association of tones with odors while sleep. This shows that our senses are definitely at work while we sleep!

What, and How Much Can We Take In While Asleep?

These participants only learned a simple non-verbal response. More studies will have to be conducted to determine the extent to which we can learn during sleep. Head researcher Anat Ariz says, “There will be clear limits on what we can learn in sleep, but I speculate that they will be beyond what we have demonstrated.” Though it is unlikely that we can learn all our Algebra by listening to recordings while we are asleep, this research could have implications in treating addictive disorders, for example, by using conditioning that pairs addictive drugs with a negative connotation. As Arzi says, perhaps the best way to cure such disorders might be learning at a level of non-awareness.

You can read more about this research here.

Inception in Real Life: Scientists Figure Out How To Hack The Human Brain

Even Nolan didn’t think it could be possible when he made Inception, but it turns out that researchers at Usenix Security conference have been speaking of using a computer interface to hack the brain! Yes, it might actually be possible to enter the brain and retrieve information that you’d prefer to keep secret. Like retrieving a combination key to a safe that your dying father might have given you and you have it stored somewhere in the subconscious.

Reading the Mind

The idea is simply this: have your brain mapped by sensors (here, an EEG or Electroencephalograph is used), which pick up crucial brain activity and then sophisticated software can help understand what it is that the brain is trying to do! These are called ‘brain-computer interfaces’ (or BCI’s) for obvious reasons.

These can actually help you mentally control your computer using specific thought patterns.

The BCI from Emotiv technologies.
Controlling a video game using BCI

Machine over Mind

What is interesting is how a computer can browse through your mental database and steal away some pieces of sensitive information. Security researchers from the Universities of Oxford and Geneva and University of California, Berkeley have developed a program to be used by the software that has only one purpose – finding information like home address, debit card PIN and date of birth. They found 28 willing participants, who didn’t know about the hacking (of course, otherwise the whole exercise is futile, right?) and tested this program on them. The success rate varied from a mere 10% to a respectable 40% for different fields of sensitive data.

The four experiments

The technique is a lot like hacking passwords. The key response tracked by the program is known as a P300 response – the brainwave activity that the brain undergoes when it recognizes something familiar, like a known face, own neighbourhood, own debit card PIN and so on! The peaks in the P300 activity were noted and the analysis of this data can give a very good indication of what the right answers are!

The P300 activity. Notice the black peak indicating a high for the target stimulus
The EEG results for a target and a non-target stimulus

Future thoughts – You might know them already!

Yes, cool, innovative and scary! Imagine the chaos which will ensue if the bank manager is kidnapped and crucial information is extracted from his brain using these kinds of hacking techniques. How can a big bank cope with that threat in the not-so-far future? What about the fear of malware – say you use the BCIs to control devices, but some pop-ups show you some random numbers and your P300 activity indicates that this might actually be your PIN? How do you protect yourself against that? The only viable option seems to be to not think about it, but then that is, believe it or not, the hardest thing to do!

Maybe, militarizing your subconscious is the only way to go. Don’t be scared to dream a bit bigger – and a bit weirder.

All pictures taken from the paper below.

Paper: https://www.usenix.org/system/files/conference/usenixsecurity12/sec12-final56.pdf

Brain’s Drainage System Discovered

Our body comes with an inbuilt drainage system called the lymphatic system. The tissues in our body lie in a pool of fluid called the interstitial fluid. While most of this fluid is directly circulated and recirculated from and into the blood vessels (called the body’s circulatory system), about 1% of this fluid is re-circulated through a different route. Interstitial fluid enters a network of vessels called lymph vessels, which in turn drain excess proteins and waste material from this fluid and into larger blood vessels for recirculation or destruction. The lymphatic system is thus an accessory system that acts in parallel with the blood circulatory system to remove excess proteins and solutes from tissues.

Fluid Flow in the Brain

Apart from blood vessels, the brain also has a fluid called the cerebrospinal fluid (CSF) circulating in its outer parts. This fluid maintains brain pressure and protects the brain from physical injury. However, a system analogous to the body’s lymphatic system has not been seen in the brain till date. This is surprising because the brain has a very high metabolic rate and brain cells are particularly sensitive to the balance of chemicals in their environment. So how does brain tissue drain waste? It has been speculated that the CSF could perform the drainage role in the brain.

Injecting Fluorescent Molecules into the Brain

How does waste from the brain tissue get out of the brain? If it is through the CSF, then the question becomes—how do tissues release their waste into the CSF which has so far been found only in the sub-arachnoid space, the outer areas of the brain? Researchers from the University of Rochester injected small amounts of fluorescent ‘tracer ‘molecules into the brain’s CSF, and as the name suggests, traced the destinations of these tracers by brain scans. They found new channels through which the CSF flows, right into the brain tissue, called brain parenchyma. They could trace the paths of these molecules, and using molecules of different sizes, they could estimate the volumes of these paths through the brain.

The thick vessel is an artery in the brain of a mouse. In green is cerebrospinal fluid in a channel along the outside of the artery. [Image Credit: University of Rochester medical Center]
They found that the CSF traverses the inner parts of the brain including the space around brain tissue in hitherto unknown channels that lie parallel to and on the boundaries of the brain’s arteries and veins, formed by cells called astrocytes. Moreover, when a water-transport gene called AQP4 was deleted in mice, fluid flow through this system was suppressed, meaning that water-transport helps build up the pressure to move things along in this system using bulk-flow or convection. The water-pressure creates a pressure allowing waste to be drained away faster. The brain’s lymphatic system has thus been found, and is being referred to as the ‘glymphatic system’, called so because cells called glial cells help create pressure.

Alzheimer’s Molecule Takes This Route

The researchers went one step further and traced the path of fluorescent-tagged amyloid b, the protein responsible for Alzheimer’s disease. They found that this protein travels along this route of ‘glymphatic’ blood vessels. This insight provides therapeutic possibilities. Improving flow through this system could speed up clearance of neurodegradative molecules like amyloid-beta from the brain. Conversely, impeding or reducing flow through this system might help retain vaccines or drugs in the brain tissue for a longer period of time. If these vessels are also routes for migrating cells, could the metastasis of cancerous tumour cells be dependent on this system too?

“Waste clearance is of central importance to every organ, and there have been long-standing questions about how the brain gets rid of its waste,” said Maiken Nedergaard, M.D., D.M.Sc., lead author of the paper and co-director at the University of Rochester’s Center for Translational Neuromedicine. “This work shows that the brain is cleansing itself in a more organized way and on a much larger scale than has been realized previously.You can read about this research here and here.

Have Excellent Autobiographical Memory? Your Brain is Differently Wired.

Do you remember what happened on the 6th June, 1999? Or 19 September 2000? Well, if you can effortlessly reel off the answers, and in general recollect events in your life with remarkable accuracy, you don’t just have good memory—you’d be pleased to know that you have what is called “Highly Superior Autobiographical Memory”.

This is a newly described ability of individuals to recall events from their personal past, including the days and dates of occurrence, with high accuracy. People with strong memories don’t necessarily have HSAM. They use certain mnemonics and strategies to perfect the art of memory, and this often doesn’t extend to autobiographical memories. In a case of one of the most famous mnemonists, the patient described living his life “in a haze”. Conversely, intense rehearsal of memories does not seem to be the primary means by which people with HSAM store their rich repertoire of memories.

Having excellent autobiographical memory could be a result of your brain being structured differently. [Image Credit: flickr.com/digitalshotgun]
Having excellent autobiographical memory could be a result of your brain being structured differently. [Image Credit: flickr.com/digitalshotgun]

How Are they “Highly Superior”?

Researchers at the University of California, Irvine tried to see if this difference between high autobiographical memory and good memory was also reflected in the way these are stored in the brain. They recruited people who claimed to have extremely good autobiographical memories and performed routine memorization tests on them. They identified 11 people who had vastly superior abilities to remember events in their past. However, these people performed no better than normal individuals on these tests. Yet when it came to public or private events that occurred after age 10½, “they were remarkably better at recalling the details of their lives,” said McGaugh, senior author on the new work.

They found that HSAM participants also had obsessive tendencies, though it remains unclear if the two are linked, and if so, how. Furthermore, they found that the brains of these participants were anatomically different from the brains of normal participants in 9 structures. Using MRI, some of these regions are shown to be active while autobiographical memories are being recalled.

Cause or Effect?

It must be noted, however, that these structural differences could either be a cause of HSAM or an effect. Our brains are remarkably plastic and embody the saying ‘we are what we do’. The wiring of our brains is subject to change upon repeated patterns of activity. Thus, the difference in certain brain regions of people with HSAM could simply arise as a result of different thought patterns in these people. Either way, this research does give us more information about the intricate workings of the brain and how it resolves the details of the world we live in.

You can read about this work here. It was published in the journal Neuroscience.