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Category: neuroscience – Page 660

New discoveries of deep brain stimulation put it on par with therapeutics

Despite having remarkable utility in treating movement disorders such as Parkinson’s disease, deep brain stimulation (DBS) has confounded researchers, with a general lack of understanding of why it works at some frequencies and does not at others. Now a University of Houston biomedical engineer is presenting evidence in Nature Communications Biology that electrical stimulation of the brain at higher frequencies (100Hz) induces resonating waveforms which can successfully recalibrate dysfunctional circuits causing movement symptoms.

“We investigated the modulations in local field potentials induced by electrical stimulation of the subthalamic nucleus (STN) at therapeutic and non-therapeutic frequencies in Parkinson’s disease patients undergoing DBS surgery. We find that therapeutic high-frequency stimulation (130−180 Hz) induces high-frequency oscillations (~300 Hz, HFO) similar to those observed with pharmacological treatment,” reports Nuri Ince, associate professor of biomedical engineering.

For the past couple of decades, (DBS) has been the most important therapeutic advancement in the treatment of Parkinson’s disease, a progressive nervous system disorder that affects movement in 10 million people worldwide. In DBS, electrodes are surgically implanted in the deep brain and electrical pulses are delivered at certain rates to control tremors and other disabling motor signs associated with the .

How electrical stimulation reorganizes the brain

Recordings of neural activity during therapeutic stimulation can be used to predict subsequent changes in brain connectivity, according to a study of epilepsy patients published in JNeurosci. This approach could inform efforts to improve brain stimulation treatments for depression and other psychiatric disorders.

Corey Keller and colleagues delivered from implanted electrodes in 14 patients while recording participants’ .

Repeated sets of stimulation resulted in progressive changes to the brain’s response to simulation, with stronger responses in brain regions connected to the stimulation site.

From drugs to brain surgery—the consciousness technology of the future

Our complicated emotional lives can often feel like a prison. Insecurities, depression and anxiety can all hold us back in life. But what if we could just eliminate the mental states that we don’t want? Or enhance the moods we do? There’s every reason to believe that this may be commonplace in the future. In fact, a lot of the technology that could achieve this already exists.

More than half of us will have experienced an extended period of sadness or low mood during our lives, and about a fifth will have been diagnosed with major depression, although these figures depend a lot on the culture in which you live. The fact that mood disorders are so common – and also so difficult to treat – means that research into the future of mood modulation is constantly evolving.

If you go to a doctor in the UK with suspected depression today, you will start on a pathway of care including “talking cures” such as cognitive behavioural therapy, or drug treatments including serotonin re-uptake inhibitors like Prozac. People who do not respond to these treatments may progress to heavier regimes or combinations of drug treatments. Since most psychoactive drug treatments are associated with side effects, there is pressure to develop new treatment options that are better tolerated by most people.

Precise control of brain circuit alters mood

Stress-susceptible animals that behaved as if they were depressed or anxious were restored to relatively normal behavior by tweaking the system, according to a study appearing in the July 20 issue of Neuron.

“If you ‘turn the volume up’ on animals that hadn’t experienced stress, they start normal and then they have a problem,” said lead researcher Kafui Dzirasa, an assistant professor of psychiatry and behavioral sciences, and neurobiology. “But in the animals that had experienced stress and didn’t do well with it, you had to turn their volume up to get them back to normal. It looked like stress had turned the volume down.”

Is Seeing Believing? How Neural Oscillations Influence Our Conscious Experience

Summary: The perceptual accuracy of visual information and its subjective interpretation use separate neural mechanisms that can be manipulated independently of each other.

Source: University of Bologna

A research group from the University of Bologna discovered the first causal evidence of the double dissociation between what we see and what we believe we see: these two different mechanisms derive from the frequency and amplitude of alpha oscillations.

Effective new target for mood-boosting brain stimulation found

Researchers have found an effective target in the brain for electrical stimulation to improve mood in people suffering from depression. As reported in the journal Current Biology on November 29, stimulation of a brain region called the lateral orbitofrontal cortex (OFC) reliably produced acute improvement in mood in patients who suffered from depression at the start of the study.

Those effects were not seen in patients without symptoms, suggesting that the brain stimulation works to normalize activity in mood-related neural circuitry, the researchers say.

“Stimulation induced a pattern of activity in connected to OFC that was similar to patterns seen when patients naturally experienced positive mood states,” says Vikram Rao, of the University of California, San Francisco. “Our findings suggest that OFC is a promising new stimulation target for treatment of mood disorders.”

Study shows different brain cells process positive, negative experiences

Combining two cutting-edge techniques reveals that neurons in the prefrontal cortex are built to respond to reward or aversion, a finding with implications for treating mental illness and addictions.

The plays a mysterious yet central role in the mammalian brain. It has been linked to mood regulation, and different cells in the prefrontal cortex seem to respond to positive and negative experiences. How the prefrontal cortex governs these opposing processes of reward or aversion, however, has been largely unknown.

In a new paper published online May 26 in Cell, researchers at Stanford, led by Karl Deisseroth, have united two transformational research techniques to show how the prefrontal circuits that process positive and negative experiences are distinctly and fundamentally different from one another, both in how they function and in how they are wired to other parts of the brain.

Bionic eyes: How tech is replacing lost vision

This technology has to translate images into something the human brain can understand. Click the numbers in the interactive image below to find read about how this works.

There are a whole range of conditions, some which are picked up due to the aging process and others which may be inherited, that can cause sight deterioration.

Bionic eyes work by ‘filling in the blanks’ between what the retina perceives and how it is processed in the brain’s visual cortex, that breakdown occurs in conditions which impact the retina. It is largely these conditions which bionic eyes could help treat.

Optogenetics reveals new insights into circuits of the brain

To date, scientists have largely been in the dark with regard to how individual circuits operate in the highly branched networks of the brain. Mapping these networks is a complicated process, requiring precise measurement methods. For the first time, scientists from the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, together with researchers from the Ernst Strüngmann Institute in Frankfurt and Newcastle University in England, have now functionally proven a so far poorly understood neural connection in the visual system of monkeys using optogenetic methods. To this end, individual neurons were genetically modified so that they became sensitive to a light stimulus.

For decades microstimulation was the method of choice for activating neurons – the method proved to be reliable and accurate. That is why it is also used medically for deep stimulation. The Tübingen-based scientists were now able to show that optogenetics, a biological technique still in its infancy, delivers comparable results.

With optogenetics it is possible to directly influence the activity of neurons by light. To do this are genetically modified with the help of viruses to express light-sensitive ion channels in their cell membrane. Through blue light pulses delivered directly into the brain, the modified neurons can then be systematically activated.