My Mitochondria Clearly Aren’t Working Because This Bitch Has NO FUCKING ENERGY

New theory explains how beta waves arise in the brain

Beta rhythms, or waves of brain activity with an approximately 20 Hz frequency, accompany vital fundamental behaviors such as attention, sensation and motion and are associated with some disorders such as Parkinson’s disease. Scientists have debated how the spontaneous waves emerge, and they have not yet determined whether the waves are just a byproduct of activity, or play a causal role in brain functions. Now in a new paper led by Brown University neuroscientists, they have a specific new mechanistic explanation of beta waves to consider.

The new theory, presented in the Proceedings of the National Academy of Sciences, is the product of several lines of evidence: external brainwave readings from human subjects, sophisticated computational simulations and detailed electrical recordings from two mammalian model organisms.

“A first step to understanding beta’s causal role in behavior or pathology, and how to manipulate it for optimal function, is to understand where it comes from at the cellular and circuit level,” said corresponding author Stephanie Jones, research associate professor of neuroscience at Brown University. “Our study combined several techniques to address this question and proposed a novel mechanism for spontaneous neocortical beta. This discovery suggests several possible mechanisms through which beta may impact function.”

Making waves

The team started by using external magnetoencephalography (MEG) sensors to observe beta waves in the human somatosensory cortex, which processes sense of touch, and the inferior frontal cortex, which is associated with higher cognition.

They closely analyzed the beta waves, finding they lasted at most a mere 150 milliseconds and had a characteristic wave shape, featuring a large, steep valley in the middle of the wave.

The question from there was what neural activity in the cortex could produce such waves. The team attempted to recreate the waves using a computer model of a cortical circuitry, made up of a multilayered cortical column that contained multiple cell types across different layers. Importantly, the model was designed to include a cell type called pyramidal neurons, whose activity is thought to dominate the human MEG recordings.

They found that they could closely replicate the shape of the beta waves in the model by delivering two kinds of excitatory synaptic stimulation to distinct layers in the cortical columns of cells: one that was weak and broad in duration to the lower layers, contacting spiny dendrites on the pyramidal neurons close to the cell body; and another that was stronger and briefer, lasting 50 milliseconds (i.e., one beta period), to the upper layers, contacting dendrites farther away from the cell body. The strong distal drive created the valley in the waveform that determined the beta frequency.

Meanwhile they tried to model other hypotheses about how beta waves emerge, but found those unsuccessful.

With a model of what to look for, the team then tested it by looking for a real biological correlate of it in two animal models. The team analyzed measurements in the cortex of mice and rhesus macaques and found direct confirmation that this kind of stimulation and response occurred across the cortical layers in the animal models.

“The ultimate test of the model predictions is to record the electrical signals inside the brain,” Jones said. “These recordings supported our model predictions.”

Beta in the brain

Neither the computer models nor the measurements traced the source of the excitatory synaptic stimulations that drive the pyramidal neurons to produce the beta waves, but Jones and her co-authors posit that they likely come from the thalamus, deeper in the brain. Projections from the thalamus happen to be in exactly the right places needed to deliver signals to the right positions on the dendrites of pyramidal neurons in the cortex. The thalamus is also known to send out bursts of activity that last 50 milliseconds, as predicted by their theory.

With a new biophysical theory of how the waves emerge, the researchers hope the field can now investigate whether beta rhythms affect or merely reflect behavior and disease. Jones’s team in collaboration with Professor of Neuroscience Christopher Moore at Brown is now testing predictions from the theory that beta may decrease sensory or motor information processing functions in the brain. New hypotheses are that the inputs that create beta may also stimulate inhibitory neurons in the top layers of the cortex, or that they may may saturate the activity of the pyramidal neurons, thereby reducing their ability to process information; or that the thalamic bursts that give rise to beta occupy the thalamus to the point where it doesn’t pass information along to the cortex.

Figuring this out could lead to new therapies based on manipulating beta, Jones said.

“An active and growing field of neuroscience research is trying to manipulate brain rhythms for optimal function with stimulation techniques,” she said. “We hope that our novel finding on the neural origin of beta will help guide research to manipulate beta, and possibly other rhythms, for improved function in sensorimotor pathologies.”

For more posts like these, go to @mypsychology​

Why Number Are The Way They Are

Life from the perspective of colour blind people 

Deuteranomalia: This is caused by reduced sensitivity to green light. Deutan color vision deficiencies are by far the most common forms of color blindness. This subtype of red-green color blindness is found in about 6% of the male population, mostly in its mild form deuteranomaly.

Protanopia: Caused by a reduced sensitivity to red light due to either defective or a lack of long -wavelength cones (red cones). Some scientists estimate that being a protan is associated with a risk of a road accident equivalent to having a blood alcohol level of between 0.05 and 0.08 per cent.

Tritanopia:  People affected by tritan color blindness confuse blue with green and yellow with violet.  This is due to a defective short-wavelength cone (blue cone). Whilst  Protanopia and Deuteranomalia are significantly more common in men, tritanopia affects both sexes in equal amounts.

Monochromacy: Only around 0.00003% of the world’s population suffers from total color blindness, where everything is seen in black and white. 

‘Smart fat cells’ cross blood-brain barrier to catch early brain tumors

An MRI contrast agent that can pass through the blood-brain barrier will allow doctors to detect deadly brain tumors called gliomas earlier, say Penn State College of Medicine researchers. This ability opens the door to make this fatal cancer treatable.

Gliomas are brain tumors that arise from glial cells, which help nerve cells to stay connected and send signals throughout the body.

Cancerous gliomas are uniformly fatal, with a median survival rate of 14 months from the time of diagnosis. But a new nanotechnology approach developed by Xiaoli Liu and Madhan Kumar in the Department of Neurosurgery could transform gliomas from a death sentence into a treatable condition.

Patients diagnosed with a malignant glioma can undergo surgery, chemotherapy and radiation to destroy the tumor, but the cancer will return.

“Patients typically don’t die from the tumor they initially presented with. Rather, they die from new tumors that come back in other parts of the brain,” said James Connor, Distinguished Professor of Neurosurgery.

These new gliomas tend to grow quickly and are often resistant to treatment because they spring from cancer cells that survived the first therapeutic assault. Glioma patients have follow-up MRIs to detect new brain cancers but the tests do not catch the tumors early enough to save lives.

That is because contrast agents used to outline gliomas on an MRI can only pass the protective blood-brain barrier once the tumors have grown large enough to cause damage to the barrier. Until then, the blood-brain barrier blocks 98 percent of small molecules and all large molecules from entering the brain.

To overcome this deadly limitation, Penn State researchers created “smart fat cells” called liposomes that can pass the blood-brain barrier in mice, seek out tiny cancerous gliomas like heat-seeking missiles and light them up on an MRI. The liposomes are loaded with the most commonly used contrast agent, Magnevist. On their surface, the liposomes are studded with proteins that target receptors on glioma cells.

The new contrast agent delivery system is more sensitive than traditional contrast-enhanced MRI, Connor said.

The researchers found that the liposomes entered the brain in healthy mice with uncompromised blood-brain barriers. Both the conventional and the new technique found large gliomas in mice with cancer, but only the liposome-encapsulated agent was able to detect smaller early-stage tumors. “The goal is to be able to get down to detecting single cancer cells,” Connor said.

The study was published in Journal of Neuro-Oncology.

It is not exactly known how the liposomes get past the intact blood-brain barrier, but they apparently do it without causing damage. In the study, mice showed no harm from the treatment.

This novel approach is an alternative to ultrasound, another promising method researchers are studying to get therapeutic agents into the brain. Ultrasound, however,  causes temporary disruption to the blood-brain barrier, which allows not only the therapeutic agent to enter the brain, but also blood which could have medical implications.

“Ultrasound, with all of its good qualities, is disruptive to the blood-brain barrier, whereas we can get an agent to cross it without causing disruption.” Connor said.

The researchers said that in the future, smart fat cells will deliver chemotherapeutic drugs, along with contrast agents, to brain tumor patients so that cancer cells can be detected and wiped out in one step. They recently presented research on these next-generation liposomes at the Society for Neuro-Oncology meeting in San Antonio.

Today’s Google Doodle:

George Boole’s 200th Birthday

Better late than never!

This week’s entry: Hot Jupiters

http://www.space.com/32011-extremely-hot-and-fast-planets-seem-to-defy-logic.html

https://astrobites.org/2015/03/04/hot-jupiters-are-very-bad-neighbors/

For more posts like these, go to @mypsychology​

One of the most dangerous pictures ever taken - Elephant’s Foot, Chernobyl. This is a photo of a now dead man next the ‘Elephant’ Foot’ at the Chernobyl power plant. 

The image distortions in the photo are created by intense level of radiation almost beyond comprehension. There is no way the person in this photo and the person photographing him could have survived for any more that a few years after being there, even if they quickly ran in, took the photos and ran out again. This photo would be impossible to take today as the rates of radioactive decay are even more extreme now due to a failed military experiment to bomb the reactor core with neuron absorbers.  The foot is made up of a small percentage of uranium with the bulk mostly melted sand, concrete and other materials which the molten corium turns into a kind of lava flow. In recent years, it has destroyed a robot which tried to approach it, and the last photos were taken via a mirror mounted to a pole held at the other end of the corridor for a few seconds. It is almost certainly the most dangerous and unstable creation made by humans.  These are the effects of exposure: 30 seconds of exposure - dizziness and fatigue a week later 2 minutes of exposure - cells begin to hemorrhage (ruptured blood vessels) 4 minutes - vomiting, diarrhea, and fever  300 seconds - two days to live