utcjonesobservatory:

You Can Now Access All Of Richard Feynmans Physics Lectures For Free: 
 
The lectures of Nobel Prize winning physicist Richard Feynman were legendary. Footage of these lectures does exist, but they are most famously preserved in The Feynman Lectures. The three-volume set may be the most popular collection of physics books ever written, and now you can access it online, in its entirety, for free.
The complete online edition of The Feynman Lectures on Physics has been made available in HTML 5 through a collaboration between Caltech (where Feyman first delivered these talks, in the early 1960s) and The Feynman Lectures Website. The online edition is “high quality up-to-date copy of Feynman’s legendary lectures,” and, thanks to the implementation of scalable vector graphics, “has been designed for ease of reading on devices of any size or shape; text, figures and equations can all be zoomed without degradation.”
Volume I deals mainly with mechanics, radiation and heat; Volume II with electromagnetism and matter; and Volume III with quantum mechanics.
Go. Have fun. 
[The Feynman Lectures on Physics via Open Culture]
high resolution →

utcjonesobservatory:

You Can Now Access All Of Richard Feynmans Physics Lectures For Free:

 

The lectures of Nobel Prize winning physicist Richard Feynman were legendary. Footage of these lectures does exist, but they are most famously preserved in The Feynman Lectures. The three-volume set may be the most popular collection of physics books ever written, and now you can access it online, in its entirety, for free.

The complete online edition of The Feynman Lectures on Physics has been made available in HTML 5 through a collaboration between Caltech (where Feyman first delivered these talks, in the early 1960s) and The Feynman Lectures Website. The online edition is “high quality up-to-date copy of Feynman’s legendary lectures,” and, thanks to the implementation of scalable vector graphics, “has been designed for ease of reading on devices of any size or shape; text, figures and equations can all be zoomed without degradation.”

Volume I deals mainly with mechanics, radiation and heat; Volume II with electromagnetism and matter; and Volume III with quantum mechanics.

Go. Have fun.

[The Feynman Lectures on Physics via Open Culture]

How Far, the Stars? Quasars Solve ‘Seven Sisters’ Star Cluster Mystery
By: Elizabeth Howell | Space.com
Super-bright galaxies powered by black holes have helped astronomers come up with the most accurate distance yet to the iconic Pleiades star cluster.
The measurement, which used quasars as bright and consistent relative-distance markers, charted the famous “Seven Sisters” star cluster at 136.2 parsecs, or 444 light-years, away from Earth.
Continue Reading
high resolution →

How Far, the Stars? Quasars Solve ‘Seven Sisters’ Star Cluster Mystery

By: Elizabeth Howell | Space.com

Super-bright galaxies powered by black holes have helped astronomers come up with the most accurate distance yet to the iconic Pleiades star cluster.

The measurement, which used quasars as bright and consistent relative-distance markers, charted the famous “Seven Sisters” star cluster at 136.2 parsecs, or 444 light-years, away from Earth.

Continue Reading

plays

teded:

View the TED-Ed Lesson What happens when you remove the hippocampus?

When Henry Molaison (now widely known as H.M.) cracked his skull in an accident, he began blacking out and having seizures. In an attempt to cure him, daredevil surgeon Dr. William Skoville removed H.M.’s hippocampus. Luckily, the seizures did go away — but so did his long-term memory! Sam Kean walks us through this astonishing medical case, detailing everything H.M. taught us about the brain and memory.

Young Stellar Object SSTC2D J033038.2+303212
Image Credit: ESO/Hubble & NASA
high resolution →

Young Stellar Object SSTC2D J033038.2+303212

Image Credit: ESO/Hubble & NASA

(Source: space.com)

Some people can hold huge amounts of information in their mind and even manipulate it, trying out different ideas, while other people can only hold small amounts. Why do people have the particular capacity they have? How can we investigate these differences between people? It turns out the key to answering these questions is to get people to remember information in only one of their five senses, for example, vision. By doing this we narrow down the field of things to investigate. We can look at the precise brain anatomy related to just that one sense in different people and figure out which parts of their brain allow for greater information capacity. This is exactly what we did in our Cerebral Cortex paper. We found that people with a physically larger visual cortex – the part at the back of the brain that deals with what we see – could hold more temporary information in their memory. This is interesting for a number of reasons because it suggests that the physical parameters of our brains set the limits to what we can do with our minds.

The larger your visual cortex the more visual information it can hold. But the “visual cortex bucket” has to actively hold on to the information. It takes voluntary effort on your behalf to continually hold this information and then use it.

It is worth noting that size is not everything. Many other brain factors can and will influence your mental life and indeed your working memory capacity.

These factors include the degree of internal connections between different brain areas, the level of neural transmitters, the hormones in your body and brain, and of course the amount of stress you are under.

In our study, we found that both the thickness and the surface size of the visual cortex independently predicted how much people could hold in visual working memory. So indirectly at least, it seems that your parents or ancestors might have passed their visual cortex down to you, or at least its size.

Brain size matters when it comes to remembering (via myserendipities) —

White Dwarfs May Hold Nuclear Trigger for Explosive Supernovas
Supernovas, the most powerful stellar explosions in the universe, may result from catastrophic nuclear explosions on dead stars, new research shows. Scientists had long theorized that such nuclear events cause some supernovas, but now researchers finally have direct evidence.
A supernova shines brightly enough to briefly outshine all the stars in its galaxy, making it visible from halfway across the universe. Such explosions are rare, only occurring within each galaxy about every 100 years.
Continue Reading
high resolution →

White Dwarfs May Hold Nuclear Trigger for Explosive Supernovas

Supernovas, the most powerful stellar explosions in the universe, may result from catastrophic nuclear explosions on dead stars, new research shows. Scientists had long theorized that such nuclear events cause some supernovas, but now researchers finally have direct evidence.

A supernova shines brightly enough to briefly outshine all the stars in its galaxy, making it visible from halfway across the universe. Such explosions are rare, only occurring within each galaxy about every 100 years.

Continue Reading

thedemon-hauntedworld:

IC443 - IC444. The Jellyfish Nebula, Supernova Remnant in Gemini
The Jellyfish nebula (IC443) in Gemini is a supernova remnant that is from 8000 years ago (3.000 - 30.000). Although it shares some characteristics with other supernova remnants like the Crab nebula, in this case, the gas threads do hot show a regular outward expansion. The nebular area on the bottom of the image is IC444. The more prominent stars are Mu and Eta Geminorum.
Credit: Antonio Perez Astronomia
high resolution →

thedemon-hauntedworld:

IC443 - IC444. The Jellyfish Nebula, Supernova Remnant in Gemini

The Jellyfish nebula (IC443) in Gemini is a supernova remnant that is from 8000 years ago (3.000 - 30.000). Although it shares some characteristics with other supernova remnants like the Crab nebula, in this case, the gas threads do hot show a regular outward expansion. The nebular area on the bottom of the image is IC444. The more prominent stars are Mu and Eta Geminorum.

Credit: Antonio Perez Astronomia

Power of the Sun: Elusive Solar Neutrinos Detected, a Cosmic First
Tiny particles forged in the heart of the sun have been detected for the first time, offering scientists a glimpse into the nuclear fusion core of our closest star.
The subatomic particles, called neutrinos, are hallmarks of the dominant fusion process insidethe sun. Created in the first step of a reaction sequence responsible for the majority of the sun’s fusion, the particles have long eluded detection. Now, an international collaboration of more than 100 scientists working with the Borexino detector in Italy has made the first measurements of these elusive particles.
Continue Reading
high resolution →

Power of the Sun: Elusive Solar Neutrinos Detected, a Cosmic First

Tiny particles forged in the heart of the sun have been detected for the first time, offering scientists a glimpse into the nuclear fusion core of our closest star.

The subatomic particles, called neutrinos, are hallmarks of the dominant fusion process insidethe sun. Created in the first step of a reaction sequence responsible for the majority of the sun’s fusion, the particles have long eluded detection. Now, an international collaboration of more than 100 scientists working with the Borexino detector in Italy has made the first measurements of these elusive particles.

Continue Reading

neurosciencestuff:

Treating Mental Illness by Changing Memories of Things Past
In the novel À larecherche du temps perdu (translated into English as Remembrance of Things Past), Marcel Proust makes a compelling case that our identities and decisions are shaped in profound and ongoing ways by our memories.
This truth is powerfully reflected in mental illnesses,like post traumatic stress disorder (PTSD) and addictions. In PTSD, memories of traumas intrude vividly upon consciousness, causing distress, driving people to avoid reminders of their traumas, and increasing risk for addiction and suicide. In addiction, memories of drug use influence reactions to drug-related cues and motivate compulsive drug use.
What if one could change these dysfunctional memories? Although we all like to believe that our memories are reliable and permanent, it turns out that memories may indeed be plastic.
The process for modifying memories, depicted in the graphic, is called memory reconsolidation. After memories are formed and stored, subsequent retrieval may make them unstable. In other words, when a memory is activated, it also becomes open to revision and reconsolidation in a new form.
"Memory reconsolidation is probably among the most exciting phenomena in cognitive neuroscience today. It assumes that memories may be modified once they are retrieved which may give us the great opportunity to change seemingly robust, unwanted memories," explains Dr. Lars Schwabe of Ruhr-University Bochum in Germany. He and his colleagues have authored a review paper on the topic, published in the current issue of Biological Psychiatry.
The idea of memory reconsolidation was initially discovered and demonstrated in rodents.
The first evidence of reconsolidation in humans was reported in a study in 2003, and the findings have since continued to accumulate. The current report summarizes the most recent findings on memory reconsolidation in humans and poses additional questions that must be answered by future studies.
"Reconsolidation appears to be a fundamental process underlying cognitive and behavioral therapies. Identifying its roles and mechanisms is an important step forward to fully harnessing the reconsolidation process in psychotherapy," said Dr. John Krystal, Editor of Biological Psychiatry.
The translation of the animal data to humans is a vital step for the potential application of memory reconsolidation in the context of mental disorders. Memory reconsolidation could open the door to novel treatment approaches for disorders such as PTSD or drug addiction.
high resolution →

neurosciencestuff:

Treating Mental Illness by Changing Memories of Things Past

In the novel À larecherche du temps perdu (translated into English as Remembrance of Things Past), Marcel Proust makes a compelling case that our identities and decisions are shaped in profound and ongoing ways by our memories.

This truth is powerfully reflected in mental illnesses,like post traumatic stress disorder (PTSD) and addictions. In PTSD, memories of traumas intrude vividly upon consciousness, causing distress, driving people to avoid reminders of their traumas, and increasing risk for addiction and suicide. In addiction, memories of drug use influence reactions to drug-related cues and motivate compulsive drug use.

What if one could change these dysfunctional memories? Although we all like to believe that our memories are reliable and permanent, it turns out that memories may indeed be plastic.

The process for modifying memories, depicted in the graphic, is called memory reconsolidation. After memories are formed and stored, subsequent retrieval may make them unstable. In other words, when a memory is activated, it also becomes open to revision and reconsolidation in a new form.

"Memory reconsolidation is probably among the most exciting phenomena in cognitive neuroscience today. It assumes that memories may be modified once they are retrieved which may give us the great opportunity to change seemingly robust, unwanted memories," explains Dr. Lars Schwabe of Ruhr-University Bochum in Germany. He and his colleagues have authored a review paper on the topic, published in the current issue of Biological Psychiatry.

The idea of memory reconsolidation was initially discovered and demonstrated in rodents.

The first evidence of reconsolidation in humans was reported in a study in 2003, and the findings have since continued to accumulate. The current report summarizes the most recent findings on memory reconsolidation in humans and poses additional questions that must be answered by future studies.

"Reconsolidation appears to be a fundamental process underlying cognitive and behavioral therapies. Identifying its roles and mechanisms is an important step forward to fully harnessing the reconsolidation process in psychotherapy," said Dr. John Krystal, Editor of Biological Psychiatry.

The translation of the animal data to humans is a vital step for the potential application of memory reconsolidation in the context of mental disorders. Memory reconsolidation could open the door to novel treatment approaches for disorders such as PTSD or drug addiction.

Comet Jacques (C/2014 E2)
Image Credit: Rolando Ligustri
high resolution →

Comet Jacques (C/2014 E2)

Image Credit: Rolando Ligustri

(Source: astronomy.com)

Holographic universe experiment begins
The Holometer experiment will test whether our universe is coded into 2-D packets many trillion times smaller than an atom.
A unique experiment at Fermi National Accelerator Laboratory has started collecting data that will answer some mind-bending questions about our universe—including whether we live in a hologram.
Much like characters on a television show would not know that their seemingly 3-D world exists only on a 2-D screen, we could be clueless that our 3-D space is just an illusion. The information about everything in our universe could actually be encoded in tiny packets in two dimensions.
Continue Reading
high resolution →

Holographic universe experiment begins

The Holometer experiment will test whether our universe is coded into 2-D packets many trillion times smaller than an atom.

A unique experiment at Fermi National Accelerator Laboratory has started collecting data that will answer some mind-bending questions about our universe—including whether we live in a hologram.

Much like characters on a television show would not know that their seemingly 3-D world exists only on a 2-D screen, we could be clueless that our 3-D space is just an illusion. The information about everything in our universe could actually be encoded in tiny packets in two dimensions.

Continue Reading

neurosciencestuff:

Bioengineers Create Functional 3D Brain-like Tissue

Bioengineers have created three-dimensional brain-like tissue that functions like and has structural features similar to tissue in the rat brain and that can be kept alive in the lab for more than two months.

As a first demonstration of its potential, researchers used the brain-like tissue to study chemical and electrical changes that occur immediately following traumatic brain injury and, in a separate experiment, changes that occur in response to a drug. The tissue could provide a superior model for studying normal brain function as well as injury and disease, and could assist in the development of new treatments for brain dysfunction.

The brain-like tissue was developed at the Tissue Engineering Resource Center at Tufts University, Boston, which is funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) to establish innovative biomaterials and tissue engineering models. David Kaplan, Ph.D., Stern Family Professor of Engineering at Tufts University is director of the center and led the research efforts to develop the tissue.

Currently, scientists grow neurons in petri dishes to study their behavior in a controllable environment. Yet neurons grown in two dimensions are unable to replicate the complex structural organization of brain tissue, which consists of segregated regions of grey and white matter. In the brain, grey matter is comprised primarily of neuron cell bodies, while white matter is made up of bundles of axons, which are the projections neurons send out to connect with one another. Because brain injuries and diseases often affect these areas differently, models are needed that exhibit grey and white matter compartmentalization.

Recently, tissue engineers have attempted to grow neurons in 3D gel environments, where they can freely establish connections in all directions. Yet these gel-based tissue models don’t live long and fail to yield robust, tissue-level function. This is because the extracellular environment is a complex matrix in which local signals establish different neighborhoods that encourage distinct cell growth and/or development and function. Simply providing the space for neurons to grow in three dimensions is not sufficient.

Now, in the Aug. 11th early online edition of the journal Proceedings of the National Academy of Sciences, a group of bioengineers report that they have successfully created functional 3D brain-like tissue that exhibits grey-white matter compartmentalization and can survive in the lab for more than two months.

“This work is an exceptional feat,” said Rosemarie Hunziker, Ph.D., program director of Tissue Engineering at NIBIB. “It combines a deep understand of brain physiology with a large and growing suite of bioengineering tools to create an environment that is both necessary and sufficient to mimic brain function.”

The key to generating the brain-like tissue was the creation of a novel composite structure that consisted of two biomaterials with different physical properties: a spongy scaffold made out of silk protein and a softer, collagen-based gel. The scaffold served as a structure onto which neurons could anchor themselves, and the gel encouraged axons to grow through it.

To achieve grey-white matter compartmentalization, the researchers cut the spongy scaffold into a donut shape and populated it with rat neurons. They then filled the middle of the donut with the collagen-based gel, which subsequently permeated the scaffold. In just a few days, the neurons formed functional networks around the pores of the scaffold, and sent longer axon projections through the center gel to connect with neurons on the opposite side of the donut. The result was a distinct white matter region (containing mostly cellular projections, the axons) formed in the center of the donut that was separate from the surrounding grey matter (where the cell bodies were concentrated).

Over a period of several weeks, the researchers conducted experiments to determine the health and function of the neurons growing in their 3D brain-like tissue and to compare them with neurons grown in a collagen gel-only environment or in a 2D dish. The researchers found that the neurons in the 3D brain-like tissues had higher expression of genes involved in neuron growth and function. In addition, the neurons grown in the 3D brain-like tissue maintained stable metabolic activity for up to five weeks, while the health of neurons grown in the gel-only environment began to deteriorate within 24 hours. In regard to function, neurons in the 3D brain-like tissue exhibited electrical activity and responsiveness that mimic signals seen in the intact brain, including a typical electrophysiological response pattern to a neurotoxin.

Because the 3D brain-like tissue displays physical properties similar to rodent brain tissue, the researchers sought to determine whether they could use it to study traumatic brain injury. To simulate a traumatic brain injury, a weight was dropped onto the brain-like tissue from varying heights. The researchers then recorded changes in the neurons’ electrical and chemical activity, which proved similar to what is ordinarily observed in animal studies of traumatic brain injury.

Kaplan says the ability to study traumatic injury in a tissue model offers advantages over animal studies, in which measurements are delayed while the brain is being dissected and prepared for experiments. “With the system we have, you can essentially track the tissue response to traumatic brain injury in real time,” said Kaplan. “Most importantly, you can also start to track repair and what happens over longer periods of time.”

Kaplan emphasized the importance of the brain-like tissue’s longevity for studying other brain disorders. “The fact that we can maintain this tissue for months in the lab means we can start to look at neurological diseases in ways that you can’t otherwise because you need long timeframes to study some of the key brain diseases,” he said.

Hunziker added, “Good models enable solid hypotheses that can be thoroughly tested. The hope is that use of this model could lead to an acceleration of therapies for brain dysfunction as well as offer a better way to study normal brain physiology.”

Kaplan and his team are looking into how they can make their tissue model more brain-like. In this recent report, the researchers demonstrated that they can modify their donut scaffold so that it consists of six concentric rings, each able to be populated with different types of neurons. Such an arrangement would mimic the six layers of the human brain cortex, in which different types of neurons exist.

As part of the funding agreement for the Tissue Engineering Resource Center, NIBIB requires that new technologies generated at the center be shared with the greater biomedical research community.

We look forward to building collaborations with other labs that want to build on this tissue model,” said Kaplan.

child-of-thecosmos:

Fiery Looping Rain on the Sun [Full HQ video]

Eruptive events on the sun can be wildly different. Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the sun’s atmosphere, the corona.

On July 19, 2012, an eruption occurred on the sun that produced all three. A moderately powerful solar flare exploded on the sun’s lower right hand limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the sun treated viewers to one of its dazzling magnetic displays — a phenomenon known as coronal rain.

spring-of-mathematics:

Infinity …    
      … it’s not big …
      … it’s not huge …
      … it’s not tremendously large …
      … it’s not extremely humongously enormous …
      … it’s

       …Endless!

Infinity has no end. Infinity is the idea of something that has no end.

"Paul Erdős lived in Budapest, Hungary, with his Mama. Mama loved Paul to infinity ∞. When Paul was 3. She had to go back to work as a math teacher….” (Extract from the book: The Boy Who Loved Math: The Improbable Life of Paul Erdős by Deborah Heiligman - Figure 1).

Infinity, most often denoted as infty(symbol:∞), is an unbounded quantity that is greater than every real number, is an abstract concept describing something without any limit and is relevant in a number of fields, predominantly mathematics and physics. In number systems incorporating infinitesimals, the reciprocal of an infinitesimal is an infinite number, i.e., a number greater than any real number. Infinity is a very tricky concept to work with, as evidenced by some of the counterintuitive results that follow from Georg Cantor’s treatment of infinite sets.
Georg Cantor formalized many ideas related to infinity and infinite sets during the late 19th and early 20th centuries. In the theory he developed, there are infinite sets of different sizes (called cardinalities). For example, the set of integers is countably infinite, while the infinite set of real numbers is uncountable. (Here is one of Proofs)

  • In Geometry and topology: Main article: Dimension (vector space). Infinite-dimensional spaces are widely used in geometry and topology, particularly as classifying spaces, notably Eilenberg−MacLane spaces. Common examples are the infinite-dimensional complex projective space K(Z,2) and the infinite-dimensional real projective space K(Z/2Z,1).
  • In Fractal Geometry: The structure of a fractal object is reiterated in its magnifications. Fractals can be magnified indefinitely without losing their structure and becoming “smooth”; they have infinite perimeters—some with infinite, and others with finite surface areas. One such fractal curve with an infinite perimeter and finite surface area is the Koch snowflake.
  • In Real analysis: In real analysis, the symbol \infty, called “infinity”, is used to denote an unbounded limit. x -> ∞ means that x grows without bound, and x  -> - ∞ means the value of x is decreasing without bound.

See more at: Infinity on Wikipedia and Mathworld - What is Infinity? on MathisFun.

Reference:  Paul Erdös and the Erdös Number Project page.

Image: Koch snowflakes & The Boy Who Loved Math: The Improbable Life of Paul Erdős.

6 days ago
518 notes

#science

neurosciencestuff:

Mind and body: Scientists identify immune system link to mental illness
Children with high everyday levels of a protein released into the blood in response to infection are at greater risk of developing depression and psychosis in adulthood, according to new research which suggests a role for the immune system in mental illness.
The study, published today in JAMA Psychiatry, indicates that mental illness and chronic physical illness such as coronary heart disease and type 2 diabetes may share common biological mechanisms.
When we are exposed to an infection, for example influenza or a stomach bug, our immune system fights back to control and remove the infection. During this process, immune cells flood the blood stream with proteins such as interleukin-6 (IL-6), a tell-tale marker of infection. However, even when we are healthy, our bodies carry trace levels of these proteins – known as ‘inflammatory markers’ – which rise exponentially in response to infection.
Now, researchers have carried out the first ever longitudinal study – a study that follows the same cohort of people over a long period of time – to examine the link between these markers in childhood and subsequent mental illness.
A team of scientists led by the University of Cambridge studied a sample of 4,500 individuals from the Avon Longitudinal Study of Parents and Children – also known as Children of the 90s – taking blood samples at age 9 and following up at age 18 to see if they had experienced episodes of depression or psychosis. The team divided the individuals into three groups, depending on whether their everyday levels of IL-6 were low, medium or high. They found that those children in the ‘high’ group were nearly two times more likely to have experienced depression or psychosis than those in the ‘low’ group.
Dr Golam Khandaker from the Department of Psychiatry at the University of Cambridge, who led the study, says: “Our immune system acts like a thermostat, turned down low most of the time, but cranked up when we have an infection. In some people, the thermostat is always set slightly higher, behaving as if they have a persistent low level infection – these people appear to be at a higher risk of developing depression and psychosis. It’s too early to say whether this association is causal, and we are carrying out additional studies to examine this association further.”
The research indicates that chronic physical illness such as coronary heart disease and type 2 diabetes may share a common mechanism with mental illness. People with depression and schizophrenia are known to have a much higher risk of developing heart disease and diabetes, and elevated levels of IL-6 have previously been shown to increase the risk of heart disease and type 2 diabetes.
Professor Peter Jones, Head of the Department of Psychiatry and senior author of the study, says: “Inflammation may be a common mechanism that influences both our physical and mental health. It is possible that early life adversity and stress lead to persistent increase in levels of IL-6 and other inflammatory markers in our body, which, in turn, increase the risk of a number of chronic physical and mental illness.”
Indeed, low birth weight, a marker of impaired foetal development, is associated with increased everyday levels of inflammatory markers as well as greater risks of heart disease, diabetes, depression and schizophrenia in adults.
This potential common mechanism could help explain why physical exercise and diet, classic ways of reducing risk of heart disease, for example, are also thought to improve mood and help depression. The group is now planning additional studies to confirm whether inflammation is a common link between chronic physical and mental illness.
The research also hints at interesting ways of potentially treating illnesses such as depression: anti-inflammatory drugs. Treatment with anti-inflammatory agents leads to levels of inflammatory markers falling to normal. Previous research has suggested that anti-inflammatory drugs such as aspirin used in conjunction with antipsychotic treatments may be more effective than just the antipsychotics themselves. A multicentre trial is currently underway, into whether the antibiotic minocycline, used for the treatment of acne, can be used to treat lack of enjoyment, social withdrawal, apathy and other so called negative symptoms in schizophrenia. Minocycline is able to penetrate the ‘blood-brain barrier’, a highly selective permeability barrier which protects the central nervous system from potentially harmful substances circulating in our blood.
The ‘blood-brain barrier’ is also at the centre of a potential puzzle raised by research such as today’s research: how can the immune system have an effect in the brain when many inflammatory markers and antibodies cannot penetrate this barrier? Studies in mice suggest that the answer may lie in the vagus nerve, which connects the brain to the abdomen. When activated by inflammatory markers in the gut, it sends a signal to the brain, where immune cells produce proteins such as IL-6, leading to increased metabolism (and hence decreased levels) of the ‘happiness hormone’ serotonin in the brain. Similarly, the signals trigger an increase in toxic chemicals such as nitric oxide, quinolonic acid, and kynurenic acid, which are bad for the functioning of nerve cells.
high resolution →

neurosciencestuff:

Mind and body: Scientists identify immune system link to mental illness

Children with high everyday levels of a protein released into the blood in response to infection are at greater risk of developing depression and psychosis in adulthood, according to new research which suggests a role for the immune system in mental illness.

The study, published today in JAMA Psychiatry, indicates that mental illness and chronic physical illness such as coronary heart disease and type 2 diabetes may share common biological mechanisms.

When we are exposed to an infection, for example influenza or a stomach bug, our immune system fights back to control and remove the infection. During this process, immune cells flood the blood stream with proteins such as interleukin-6 (IL-6), a tell-tale marker of infection. However, even when we are healthy, our bodies carry trace levels of these proteins – known as ‘inflammatory markers’ – which rise exponentially in response to infection.

Now, researchers have carried out the first ever longitudinal study – a study that follows the same cohort of people over a long period of time – to examine the link between these markers in childhood and subsequent mental illness.

A team of scientists led by the University of Cambridge studied a sample of 4,500 individuals from the Avon Longitudinal Study of Parents and Children – also known as Children of the 90s – taking blood samples at age 9 and following up at age 18 to see if they had experienced episodes of depression or psychosis. The team divided the individuals into three groups, depending on whether their everyday levels of IL-6 were low, medium or high. They found that those children in the ‘high’ group were nearly two times more likely to have experienced depression or psychosis than those in the ‘low’ group.

Dr Golam Khandaker from the Department of Psychiatry at the University of Cambridge, who led the study, says: “Our immune system acts like a thermostat, turned down low most of the time, but cranked up when we have an infection. In some people, the thermostat is always set slightly higher, behaving as if they have a persistent low level infection – these people appear to be at a higher risk of developing depression and psychosis. It’s too early to say whether this association is causal, and we are carrying out additional studies to examine this association further.”

The research indicates that chronic physical illness such as coronary heart disease and type 2 diabetes may share a common mechanism with mental illness. People with depression and schizophrenia are known to have a much higher risk of developing heart disease and diabetes, and elevated levels of IL-6 have previously been shown to increase the risk of heart disease and type 2 diabetes.

Professor Peter Jones, Head of the Department of Psychiatry and senior author of the study, says: “Inflammation may be a common mechanism that influences both our physical and mental health. It is possible that early life adversity and stress lead to persistent increase in levels of IL-6 and other inflammatory markers in our body, which, in turn, increase the risk of a number of chronic physical and mental illness.”

Indeed, low birth weight, a marker of impaired foetal development, is associated with increased everyday levels of inflammatory markers as well as greater risks of heart disease, diabetes, depression and schizophrenia in adults.

This potential common mechanism could help explain why physical exercise and diet, classic ways of reducing risk of heart disease, for example, are also thought to improve mood and help depression. The group is now planning additional studies to confirm whether inflammation is a common link between chronic physical and mental illness.

The research also hints at interesting ways of potentially treating illnesses such as depression: anti-inflammatory drugs. Treatment with anti-inflammatory agents leads to levels of inflammatory markers falling to normal. Previous research has suggested that anti-inflammatory drugs such as aspirin used in conjunction with antipsychotic treatments may be more effective than just the antipsychotics themselves. A multicentre trial is currently underway, into whether the antibiotic minocycline, used for the treatment of acne, can be used to treat lack of enjoyment, social withdrawal, apathy and other so called negative symptoms in schizophrenia. Minocycline is able to penetrate the ‘blood-brain barrier’, a highly selective permeability barrier which protects the central nervous system from potentially harmful substances circulating in our blood.

The ‘blood-brain barrier’ is also at the centre of a potential puzzle raised by research such as today’s research: how can the immune system have an effect in the brain when many inflammatory markers and antibodies cannot penetrate this barrier? Studies in mice suggest that the answer may lie in the vagus nerve, which connects the brain to the abdomen. When activated by inflammatory markers in the gut, it sends a signal to the brain, where immune cells produce proteins such as IL-6, leading to increased metabolism (and hence decreased levels) of the ‘happiness hormone’ serotonin in the brain. Similarly, the signals trigger an increase in toxic chemicals such as nitric oxide, quinolonic acid, and kynurenic acid, which are bad for the functioning of nerve cells.