Getting Enraged By Specific Noises Has A Genuine Neurological Basis. Does The Sound Of Whistling Enrage

What Happens in the Brain During Unconsciousness?

Researchers are shining a light on the darkness of the unconscious brain. Three new studies add to the body of knowledge.

When patients undergo major surgery, they’re often put under anesthesia to allow the brain to be in an unconscious state.

But what’s happening in the brain during that time?

Three Michigan Medicine researchers are authors on three new articles from the Center for Consciousness Science exploring this question — specifically how brain networks fragment in association with a variety of unconsciousness states.

“These studies come from a long-standing hypothesis my colleagues and I have had regarding the essential characteristic of why we are conscious and how we become unconscious, based on patterns of information transfer in the brain,” says George A. Mashour, M.D., Ph.D., professor of anesthesiology, director of the Center for Consciousness Science and associate dean for clinical and translational research at the University of Michigan Medical School.

In the studies, the team not only explores how the brain networks fragment, but also how better to measure what is happening.

“We’ve been working for a decade to understand in a more refined way how the spatial and temporal aspects of brain function break down during unconsciousness, how we can measure that breakdown and the implications for information processing,” says UnCheol Lee, Ph.D., physicist, assistant professor of anesthesiology and associate director of the Center for Consciousness Science.

Examining different aspects of unconsciousness

The basis for the three studies, as well as other work from the Center for Consciousness Science, comes from a theory Mashour produced during his residency.

“I published a theoretical article when I was a resident in anesthesiology suggesting that anesthesia doesn’t work by turning the brain off, per se, but rather by isolating processes in certain areas of the brain,” Mashour says. “Instead of seeing a highly connected brain network, anesthesia results in an array of islands with isolated cognition and processing. We have taken this thought, as well as the work of others, and built upon it with our research.”

In the study in the Journal of Neuroscience, the team analyzed different areas of the brain during sedation, surgical anesthesia and a vegetative state.

“It’s often suggested that different areas of the brain that typically talk to one another get out of sync during unconsciousness,” says Anthony Hudetz, Ph.D., professor of anesthesiology, scientific director of the Center for Consciousness Science and senior author on the study. “We showed in the early stages of sedation, the information processing timeline gets much longer and local areas of the brain become more tightly connected within themselves. That tightening might lead to the inability to connect with distant areas.”

In the Frontiers in Human Neuroscience study, the team delved into how the brain integrates information and how it can be measured in the real world.

“We took a very complex computational task of measuring information integration in the brain and broke it down into a more manageable task,” says Lee, senior author on the study. “We demonstrated that as the brain gets more modular and has more local conversations, the measure of information integration starts to decrease. Essentially, we looked at how the brain network fragmentation was taking place and how to measure that fragmentation, which gives us the sense of why we lose consciousness.”

Finally, the latest article, in Trends in Neurosciences, aimed to take the team’s previous studies and other work on the subject of unconsciousness and put together a fuller picture.

“We examined unconsciousness across three different conditions: physiological, pharmacological and pathological,” says Mashour, lead author on the study. “We found that during unconsciousness, disrupted connectivity in the brain and greater modularity are creating an environment that is inhospitable to the kind of efficient information transfer that is required for consciousness.”

How these studies can help patients

The team members at the Center for Consciousness Science note that all of this work may help patients in the future.

“We’re looking for a better way to quantify the depth of anesthesia in the operating room and to assess consciousness in someone who has had a stroke or brain damage,” Hudetz says. “For example, we may assume that a patient is fully unconscious based on behavior, but in some cases consciousness can persist despite unresponsiveness.”

The team hopes this and future research could lead to therapeutic strategies for patients.

“We want to understand the communication breakdown that occurs in the brain during unconsciousness so we can precisely target or monitor these circuits to achieve safer anesthesia and restore these circuits to improve outcomes of coma,” Mashour says.

After Centuries, Scientists Have Finally Figured Out How Water Conducts Electricity

One of life's most fundamental processes has been witnessed.

It’s a textbook moment centuries in the making: more than 200 years after scientists started investigating how water molecules conduct electricity, a team has finally witnessed it happening first-hand.

It’s no surprise that most naturally ocurring water conducts electricity incredibly well - that’s a fact most of us have been taught since primary school. But despite how fundamental the process is, no one had been able to figure out how it actually happens on the atomic level.

“This fundamental process in chemistry and biology has eluded a firm explanation,” said one of the team, Anne McCoy from the University of Washington. “And now we have the missing piece that gives us the bigger picture: how protons essentially ‘move’ through water.”

Continue Reading.

For those poorly informed (educated) who insist that vaccines are just the same as catching the illness…. This is just one example of why that is not true.

Breakthrough for vaccine research: Mucosa forms special immunological memory

If a vaccine is to protect the intestines and other mucous membranes in the body, it also needs to be given through the mucosa, for example as a nasal spray or a liquid that is drunk. The mucosa forms a unique immunological antibody memory that does not occur if the vaccine is given by injection. This has been shown by a new study from Sahlgrenska Academy published in Nature Communications.                                

Immunological memory is the secret to human protection against various diseases and the success of vaccines. It allows our immune system to quickly recognize and neutralize threats. “The largest part of the immune system is in our mucosa. Even so, we understand less about how immunological memory protects us there than we do about protection in the rest of the body. Some have even suggested that a typical immune memory function does not exist in the mucosa,” says Mats Bemark, associate professor of immunology at Sahlgrenska Academy, University of Gothenburg.

After extensive work, the research team at Sahlgrenska Academy can now show that this assumption is completely wrong.

Mats Bemark et al. Limited clonal relatedness between gut IgA plasma cells and memory B cells after oral immunization, Nature Communications (2016). DOI: 10.1038/ncomms12698

Autonomic nervous system

Structure and Function of the Sympathetic and Parasympathetic nervous system

The main function of the autonomic nervous system (ANS) is to assist the body in maintaining a relatively constant internal environment. For example, a sudden increase in systemic blood pressure activates the baroreceptors (those are receptors that detect physical pressure) which in turn modify the activity of the ANS so that the blood pressure is restored to its previous level [1].

The ANS is often regarded as a part of the motor system and is responsible for involuntary action and its effector organs are smooth muscle, cardiac muscle and glands. Another system, the somatic (meaning around the body) nervous system, is responsible for voluntary action in which skeletal muscle is the effector.

The ANS can further be divided into 3 parts: sympathetic, parasympathetic and enteric nervous systems [1][2], with the enteric nervous system sometimes being considered a separate entity [2]. Both parasympathetic and sympathetic nervous systems coexist and work in opposition with each other, ultimately maintaining the correct balance; the activity of one being more active depending on the situation. In a normal resting human, the parasympathetic nervous system dominates, while in a tense and stressful situation, the sympathetic nervous system switches to become dominant.

Figure 1. Structure and function of the central nervous system

This article will be focused on sympathetic and parasympathetic activity from the perspective of:

Anatomy

Biochemical

The sympathetic division provides your “fight or flight” whereas the parasympathetic division helps you to “rest and digest”

Anatomy

Higher centers that control autonomic function include the pons, medulla oblongata and hypothalamus [3].

The pons contains the micturition (urination) and respiratory center.

The medulla oblongata contains the respiratory, cardiac, vomiting, vasomotor and vasodilator centres [4].

The hypothalamus contains the highest concentration of autonomic centres [4]. It contains several centres that control autonomic activities, including heat loss, heat production and conservation, feeding and satiety, as well as fluid intake [4].

Figure 2. Locations of the autonomic control centres of the brain

All 3 structures receive input from certain sources by stimulation of nerve fibres resulting from chemical changes in blood composition like blood pH, blood glucose level, blood osmolarity and volume [4]. Notably, the hypothalamus receives input from cerebral cortex and the limbic system, a system that helps control emotional behaviour [3].

Autonomic promoter neurons are neurons that are found in the brain stem, hypothalamus or even cerebral hemispheres that project to preganglionic neurons (discussed below), where they form synapses with these neurons (5). Hence, input from the higher centres can be relayed to the motor neurons (preganglionic and then postganglionic neurons) which subsequently innervate different body tissues. Changes in the input from these centres could result in responses in those tissues.

The primary functional unit of the sympathetic and parasympathetic nervous system consists of a 2 neuron motor pathway (Figure 3), containing a preganglionic and postganglionic neurons, arranged in series.(2) The two synapse in peripheral ganglion. This clearly distinguishes autonomic motor nervous system and somatic nervous system. The somatic nervous system project from the CNS directly to innervated tissue without any intervening ganglia.(6)

Figure 3. Diagram showing the primary functional unit of the ANS

Sympathetic nervous system

Sympathetic preganglionic neurons mainly are concentrated in the lateral horn in the thoracic (T1-12) and upper lumbar (L1 &2) segments of the spinal cord (Figure 4).

The preganglionic axons leave the spinal cord in 3 ways:

Through the paravertebral ganglion

The preganglionic axon may synapse with postganglionic neurons in this ganglion or some axon may travel rostrally or caudally within the sympathetic trunk before forming synapse with a postganglionic neurons in a different paravertebral ganglion.

Through the prevertebral ganglion

Some preganglionic axons pass the paravertebral ganglion (no synapse occur) and form synapse with postganglionic neurons in prevertebral ganglion, also known as collateral ganglion.

Directly to the organs without any synapse

Some preganglionic axons pass through the sympathetic trunk (no synapse) and end directly on cells of the adrenal medulla, which are equivalent to postganglionic cell.

Parasympathetic nervous system

The parasympathetic preganglionic neurons are located in several cranial nerve nuclei in the brain stem and some are found in the S3 and S4 segments of the sacral spinal cord (Figure 4). The parasympathetic postganglionic neurons are located in cranial ganglia, including the ciliary ganglion, the pterygopalatine, submandibular ganglia, and the otic ganglion. Other ganglia are present near or in the walls of visceral organs. Similarly, the preganglionic neurons form synapse with the postganglionic neurons in the ganglia.

Figure 4. Anatomy of the ANS and how its nuerons innervate tissues

After knowing how nerves connect from the CNS to PNS and to different organs, we will now consider some of the neurotransmitters that are being released at different nerve terminals. It is the binding of these neurotransmitters to the receptors on the effectors that leads to biochemical and physiological changes. Some of the neurotransmitters in use are:

For the synapse between pre and postganglionic neurons mentioned above, the neurotransmitter that is released by the preganglionic axon terminal, is acetylcholine. The corresponding receptors are found on the postsynaptic membrane of postganglionic nerves and are nicotinic receptors.

Parasympathetic postganglionic nerve terminals also release acetylcholine.

Sympathetic postganglionic nerve terminals release mostly noradrenaline

The adrenal medulla receives direct stimulation from sympathetic preganglionic innervation, releases mainly adrenaline (80%) and some noradrenaline into the blood stream. In this case, both adrenaline and noradrenaline act as hormones as they are transported via blood circulating system to target organs instead of neuronal pathway.

Strangely, for the sympathetic postganglionic nerves that innervate the sweat glands, the nerves release acetylcholine (normally only by parasympathetic postganglionic nerve) instead.

1. H.P.Rang, J.M.Ritter, R.J.Flower GH. RANG & DALE’S Pharmacology. In: 8th ed. ELSEVIER CHURCHILL LIVINGSTONE; 2016. p. 145.

2. Bruce M. Koeppen BAS. BERNE & LEVY PHYSIOLOGY. In: 6th ed. MOSBY ELSEVIER; 2010. p. 218.

3. Cholinergic transmission [Internet]. 2015. Available from: http://www.dartmouth.edu/~rpsmith/Cholinergic_Transmission.html

4. Bruce M. Koeppen BAS. BERNE & LEVY PHYSIOLOGY. In: 6th ed. MOSBY ELSEVIER; 2016. p. 44.

Viruses support photosynthesis in bacteria: An evolutionary advantage?

Viruses propagate by infecting a host cell and reproducing inside. This not only affects humans and animals, but bacteria as well. This type of virus is called bacteriophage. They carry so called auxiliary metabolic genes in their genome, which are responsible for producing certain proteins that give the virus an advantage. Researchers at the University of Kaiserslautern and the Ruhr University Bochum have analysed the structure of such a protein more closely. It appears to stimulate the photosynthesis of host bacteria. The study has now been published in the journal The Journal of Biological Chemistry.

Raphael Gasper, Julia Schwach, Jana Hartmann, Andrea Holtkamp, Jessica Wiethaus, Natascha Riedel, Eckhard Hofmann, Nicole Frankenberg-Dinkel. Auxiliary metabolic genes- Distinct Features of Cyanophage-encoded T-type Phycobiliprotein Lyase θCpeT. Journal of Biological Chemistry, 2017; jbc.M116.769703 DOI: 10.1074/jbc.M116.769703

The association between the virus protein and bacterial pigment is incredibly stable. Furthermore, the complex is highly fluorescent. Credit: AG Frankenberg-Dinkel

Neural Pathways by Alexey Kashpersky

4 new elements added to the periodic table

The seventh row of the Periodic Table of Elements is now complete, rendering all textbooks out of date. The discovered elements don’t have permanent names yet, but their atomic numbers are 113, 115, 117 and 118.

Livermore Lab scientists and international collaborators have officially discovered three of the four new elements: 115, 117 and 118. The illustration above is of 117, tentatively named ununseptium or Uus.

The new elements’ existence was confirmed by further experiments that reproduced them — however briefly. Element 113, for instance, exists for less than a thousandth of a second.

Learn more about the new elements

Archbishop Ussher’s chronology was taken as gospel in the Western world. Until we turned to another book to find the age of the earth, the one that was written in the rocks themselves.

5 sleep disorders you didn’t know existed

Ever shouted at your partner while you slept, or woken up unable to move? From apnoea to exploding heads, here are some strange things that go bump in the night.

Sleep apnoea

A surprisingly common condition in which you stop breathing for 10 seconds or more as you sleep. The lack of oxygen causes your brain to wake you up, or pull you into much lighter sleep. Either way, it can have a profound effect on the quality of your sleep – and that of any bedfellow, as it’s often accompanied by loud snoring.

Sleep paralysis

A terrifying experience, where the body, which naturally becomes paralysed duringREM sleep, is still paralysed when you wake. You are fully conscious but cannot move or speak, sometimes for several minutes. Some people also feel as if they are choking or their chest is being crushed and they may have visual hallucinations. The condition can be exacerbated by sleep deprivation, some drugs, and disorders such as sleep apnoea.

Hypnagogic jerks

Those jumps or twitches you experience as you nod off, often accompanied by the sensation of falling. The cause remains a mystery. One idea is that you start dreaming before your body becomes paralysed. Another is that the twitches are a by-product of your nervous system relaxing as you drift off.

REM sleep disorder

If you’ve ever punched or shouted at your partner in the night, only to remember nothing next morning, you may have been in the grip of this condition. Here, the body isn’t fully paralysed during REM sleep, so people act out their dreams. Thistends to happen only with bad dreams.

Exploding head syndrome

This entails the sensation of a loud noise, like an exploding bomb or a gunshot, as you drift off or wake up. It affects about 1 in 10 of us and it tends to start around age 50. Nobody knows what causes it– perhaps physical changes in the middle ear, or a minor seizure in the brain’s temporal lobe. Despite its name, the condition is harmless.

Image Credit: Toby Leigh

Source: New Scientist (By Catherine de Lange)

Are colour-changing octopuses really colourblind? 

Cephalopods, including octopuses and squid, have some of the most incredible colour-changing abilities in nature. 

They can almost instantly blend in with their surroundings to evade predators or lay in wait, and put on colourful displays to attract mates or dazzle potential prey.

This is impressive enough on its own, but becomes even more amazing when you discover these creatures are in fact colourblind – they only have one type of light receptor in their eyes, meaning they can only see in black and white.

So how do they know what colours to change to at all?

This has puzzled biologists for decades but a father/son team of scientists from the University of California, Berkeley, and Harvard University think the unusual shape of their pupils holds the key, and they can see colour after all.

Cephalopods have wide U-shaped or dumbbell-shaped pupils, which allow light into the lens from many directions.

When light enters the pupils in human eyes it gets focused on one spot, cutting down on blur from the light being split into its constituent colours.

The scientists believe cephalopod eyes work the opposite way – the wide pupils split the light up and then individual colours can be focused on the retina by changing the depth of the eyeball and moving the pupil around.  

The price for this is blurry vision, but it does mean they could make out colours in a unique way to any other animals.

Processing colour this way is more computationally intensive than other types of colour vision and likely requires a lot of brainpower, which might explain in part why cephalopods are the most intelligent invertebrates on Earth.

Read the paper

Images:  Roy Caldwell, Klaus Stiefel, Alexander Stubbs