Archive for the ‘neuroscience’ category: Page 17

Sep 2, 2020

Structural Controllability Predicts Functional Patterns and Brain Stimulation Benefits Associated with Working Memory

Posted by in categories: engineering, neuroscience

The brain is an inherently dynamic system, and much work has focused on the ability to modify neural activity through both local perturbations and changes in the function of global network ensembles. Network controllability is a recent concept in network neuroscience that purports to predict the influence of individual cortical sites on global network states and state changes, thereby creating a unifying account of local influences on global brain dynamics. While this notion is accepted in engineering science, it is subject to ongoing debates in neuroscience as empirical evidence linking network controllability to brain activity and human behavior remains scarce. Here, we present an integrated set of multimodal brain–behavior relationships derived from fMRI, diffusion tensor imaging, and online repetitive transcranial magnetic stimulation (rTMS) applied during an individually calibrated working memory task performed by individuals of both sexes. The modes describing the structural network system dynamics showed direct relationships to brain activity associated with task difficulty, with difficult-to-reach modes contributing to functional brain states in the hard task condition. Modal controllability (a measure quantifying the contribution of difficult-to-reach modes) at the stimulated site predicted both fMRI activations associated with increasing task difficulty and rTMS benefits on task performance. Furthermore, fMRI explained 64% of the variance between modal controllability and the working memory benefit associated with 5 Hz online rTMS. These results therefore provide evidence toward the functional validity of network control theory, and outline a clear technique for integrating structural network topology and functional activity to predict the influence of stimulation on subsequent behavior.

SIGNIFICANCE STATEMENT The network controllability concept proposes that specific cortical nodes are able to steer the brain into certain physiological states. By applying external perturbation to these control nodes, it is theorized that brain stimulation is able to selectively target difficult-to-reach states, potentially aiding processing and improving performance on cognitive tasks. The current study used rTMS and fMRI during a working memory task to test this hypothesis. We demonstrate that network controllability correlates with fMRI modulation because of working memory load and with the behavioral improvements that result from a multivisit intervention using 5 Hz rTMS. This study demonstrates the validity of network controllability and offers a new targeting approach to improve efficacy.

Sep 2, 2020

Mechanism for analogous illusory motion perception in flies and humans

Posted by in category: neuroscience

Most of the time, visual circuitry in our brains faithfully reports visual scenes. Sometimes, however, it can report motion in images that are in fact stationary, leading us to perceive illusory motion. In this study, we establish that fruit flies, too, perceive motion in the stationary images that evoke illusory motion in humans. Our results demonstrate how this motion illusion in flies is an artifact of the brain’s strategies for efficiently processing motion in natural scenes. Perceptual tests in humans suggest that our brains may employ similar mechanisms for this illusion. This study shows how illusions can provide insight into visual processing mechanisms and principles across phyla.

Visual motion detection is one of the most important computations performed by visual circuits. Yet, we perceive vivid illusory motion in stationary, periodic luminance gradients that contain no true motion. This illusion is shared by diverse vertebrate species, but theories proposed to explain this illusion have remained difficult to test. Here, we demonstrate that in the fruit fly Drosophila, the illusory motion percept is generated by unbalanced contributions of direction-selective neurons’ responses to stationary edges. First, we found that flies, like humans, perceive sustained motion in the stationary gradients. The percept was abolished when the elementary motion detector neurons T4 and T5 were silenced. In vivo calcium imaging revealed that T4 and T5 neurons encode the location and polarity of stationary edges.

Sep 2, 2020

Brain study reveals one type of exercise increases stress resilience

Posted by in categories: biological, food, genetics, health, neuroscience

In a recent study conducted in mice, researchers became one step closer to that understanding, discovering that exercise actually strengthens the brain’s resilience to stress. Exercise helps animals cope with stress by enabling an uptick in a crucial neural protein called galanin, the study suggests. This process influences stress levels, food consumption, cognition, and mood.

Leveraging this finding, researchers were able to genetically tweak even sedentary mice’s levels of galanin, shifts that lowered their anxious response to stress.

The study’s authors explain that this study helps pin down the biological mechanisms driving exercise’s positive effects on stress. While further human experiments are needed to confirm these findings, the researchers have practical advice for people looking to get these benefits: perform regular, aerobic exercise.

Sep 1, 2020

Gene-editing, Moderna, and transhumanism

Posted by in categories: biotech/medical, cyborgs, genetics, neuroscience, transhumanism

But U.S. is not the only country engaged in human enhancement and transhumanism, as Russia and China are also in hot pursuit with exoskeletons, vaccines and brain implants. As this competition gains traction, one wonders what the future of their militaries may look like as human beings are steadily integrated with machines to become armies of iron man.

From the blog of Christina Lin at The Times of Israel.

Sep 1, 2020

Neurons protect themselves from degeneration

Posted by in categories: biotech/medical, neuroscience

A recent study in Science Advances by researchers at Karolinska Institutet and Max Planck Institute, shows that neurons can counteract degeneration and promote survival by adapting their metabolism. It challenges the long-standing view that neurons cannot adjust their metabolism and therefore irreversibly degenerate. These findings may contribute to developing therapeutic approaches for patients with mitochondrial diseases and other types of neurodegeneration, such as Parkinson’s Disease.

Mitochondria are the power plants of our and play an important role in providing energy for normal function of the tissues in our body. Nerve cells are particularly dependent on mitochondria for their activity. A growing body of evidence has linked mitochondrial dysfunction to some of the most devastating forms of , such as Parkinson’s , different ataxias and several peripheral neuropathies.

However, despite the urge to find strategies to prevent or arrest neurodegeneration, our understanding of the precise events underlying neuronal death caused by mitochondrial dysfunction is very limited.

Sep 1, 2020

US workers under lockdown three times more likely to report mental health issues

Posted by in categories: biotech/medical, neuroscience

According to a recent survey of more than 1,500 US based respondents, workers are now three times more likely to report poor mental health than they were before the pandemic. The study also claims that seventy-five percent of people have experienced burnout at work, with 40 percent saying they’ve experienced burnout during the pandemic specifically. The report suggests that this is not surprising, given that 37 percent of employed respondents are currently working longer hours than usual since the pandemic started.

However, just 21 percent said they were able to have open, productive conversations with HR about solutions to their burnout. Fifty-six percent went so far as to say that their HR departments did not encourage conversations about burnout. This survey was conducted by FlexJobs, fielded in partnership with Mental Health America (MHA) in late July 2020.

Key findings:

Sep 1, 2020

CRISPR-edited babies born in China may have enhanced brain functions

Posted by in categories: biotech/medical, neuroscience

Fifty years after the classic Star Trek episode “Space Seed,” life imitates art…

The controversial decision to genetically edit the embryos of two girls born in China last year might have enhanced their memory and cognition, scientists say.

Chinese scientist He Jiankui reported in November that he’d used the CRISPR editing tool to delete a gene called CCR5, which enables humans to contract HIV, the virus that causes AIDS. In addition to potentially blocking the development of AIDS, recent research suggests knocking out CCR5 can also make mice smarter and help the human brain recover from strokes.

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Aug 31, 2020

What is Elon Musk doing to the brains of pigs?

Posted by in categories: Elon Musk, neuroscience

Elon Musk’s brain-machine interface company Neuralink has created a small coin-sized device capable of recording the brain and stimulating it. The company used live pigs to conduct a live demonstration of the exciting new technology. Musk is calling his latest creation a Fitbit for the brain.

Aug 31, 2020

Veterans Are Taking a Psychedelic Plant to Fight PTSD

Posted by in categories: biotech/medical, neuroscience

Veterans are spending thousands on retreats in central America where they take ayahuasca, a psychedelic drug one attendant called a “Hail Mary” for PTSD symptoms, according to The New York Times.

The psychedelic brew ayahuasca is being hailed as “a Hail Mary.”

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Aug 31, 2020

Aubrey de Grey | Keynote Speech

Posted by in categories: biotech/medical, neuroscience

In his keynote speech at Ending Age-Related Diseases 2020, Dr. Aubrey de Grey of SENS Research Foundation discusses the current state of the rejuvenation biotechnology industry in the context of the current pandemic. He mentions the failure of Unity Biotechnology’s Phase 2 clinical trial for osteoarthritis, COVID-19 and the elderly immune system, the current popularization of rejuvenation biotechnology, XPRIZE, and the steps that are currently being taken towards a world without age-related diseases.

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