Why is Alzheimer’s still a medical mystery?

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Decades of scientific research into Alzheimer’s have failed to find a cure. Little is known about the degenerative brain disease—but this may be about to change.

As populations have aged, dementia has soared to become the fifth leading cause of death worldwide. Alzheimer’s disease, a form of dementia, accounts for most of these cases. All attempts to halt the progression of the disease have failed. Now many major drug companies have pulled out of research altogether.

So why is Alzheimer’s disease still such a medical mystery?

One of the signs of Alzheimer’s in the brain is damage of connections and the loss of large numbers of neurons over time. It affects the hippocampus and its connected structures making it harder to form new memories or learn new information. As damage spreads through the brain the cortex becomes thinner and more memories are lost. Although emotional responses can often remain. As the brain shrinks further it slowly alters personality and behaviour and eventually the ability to live and function independently.

For 35 years there has been scientific disagreement about the origins of the disease. The main area of debate has focused on the abnormal build up of clumps of protein called amyloid plaques often found in brains of those affected by Alzheimer’s. But all attempts to target this protein with drugs have failed. A new study is now challenging the way science thinks about the disease. The study suggests that the bacterium Porphyromonas gingivalis, which is involved in gum disease, may contribute to Alzheimer’s.

The risk of Alzheimer’s is higher in those who have severe head injuries and also for those with an arterial disease known as atherosclerosis. This suggests there are many causes with one endpoint. And scientists hope that finding an underlying cause that could tie these together will hold the key to better treatments in the future.

Weekly Neuroscience Update

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Music and mindful music listening may help people who have suffered strokes recover their impaired cognitive abilities more effectively, new research suggests.

The loss of memory and cognitive function known to afflict survivors of septic shock is the result of a sugar that is released into the bloodstream and enters the brain during the life-threatening condition. This finding, published in the Proceedings of the National Academy of Sciences, explains the premature mental aging that follows septic shock and may shed light on memory loss in other diseases.

Researchers have identified a new autoimmune disease that causes muscle pain and weakness.

Scientists used brain signals recorded from epilepsy patients to program a computer to mimic natural speech–an advancement that could one day have a profound effect on the ability of certain patients to communicate.

Scientists have created a “neural decoder” that translates brain activity into speech.

Autism diagnosis becomes stable starting at 14 months of age, researchers report. The accurate diagnosis of ASD, four months earlier than previously believed, leads to more opportunities for early interventions.

A new two-tier diagnostic blood test which evaluates both amyloid beta and tau, can help detect Alzheimer’s disease in presymptomatic patients.

Researchers are officially defining a new brain disorder that mimics Alzheimer’s disease. The disorder will be known as LATE, which stands for limbic-predominant age-related TDP-43 encephalopathy.

Finally this week, a new deep learning algorithm can reliably determine what visual stimuli neurons in the visual cortex respond best to.

 

Weekly Neuroscience Update

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Image: Pixabay

How quickly do we experience the benefits of exercise? A new study of healthy older adults shows that just one session of exercise increased activation in the brain circuits associated with memory – including the hippocampus – which shrinks with age and is the brain region attacked first in Alzheimer’s disease.

Using a unique computational framework they developed, a team of scientist cyber-sleuths has identified 104 high-risk genes for schizophrenia.

Reduced connectivity between the amygdala and ventrolateral prefrontal cortex has been identified in children on the autism spectrum who exhibit disruptive behaviors, compared to those on the spectrum who do not. Findings suggest this distinct brain network could be independent of core autism symptoms.

A specially designed computer program can help diagnose post-traumatic stress disorder (PTSD) in veterans by analyzing their voices.

Using CRISPR-Cas9 gene editing, researchers identified actionable pathways responsible for the growth of glioblastoma stem cells. By reverse engineering brain cancer cells, multiple potential new targets for cancer treatments have been uncovered.

Obesity is associated with alterations in brain structure, including lower grey matter volume and smaller globus pallidus volume according to new research. 

Researchers have found certain clues in the brain waves that show the reason why angry dreams occur when a person sleeps. The results of the study titled, “EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations Over the Right Frontal Cortex During REM Sleep and Pre-Sleep Wakefulness Predict Anger in REM Sleep Dreams,” were published in the Journal of Neuroscience.

People with the specific genotype of the Cannabinoid receptor 1 gene may be more prone to cannabis use disorder.

A rapid memory system transition from the hippocampus to the posterior parietal cortex is stabilized as we sleep. Sleep and repeated rehearsal of memory jointly contribute to long-term memory consolidation.

A new study confirms that a simple blood test can reveal whether there is accelerating nerve cell damage in the brain. 

Finally, this week, using a combination of movie clips and neuroimaging, researchers find people have positive biases to those they feel are more like them, even if they are unable to see the person’s face.

Weekly Neuroscience Update

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TDP-43 inclusions are found in cells in the central nervous system. Image Credit: M. Oktar Guloglu, Wikimedia Commons

A team of researchers is fishing for a new method to treat neurodegenerative disorders. Its tactic? Bait dysfunctional proteins and prevent them from joining together into the kind of toxic globs found in almost every patient with ALS or frontotemporal dementia (FTD).

A ‘hit-and-run’ interaction between two proteins could be an important trigger for cell death, according to new research.

Biomedical engineers at Duke University have developed an automated process that can trace the shapes of active neurons as accurately as human researchers can, but in a fraction of the time.

Zapping the brains of people over 60 with a mild electrical current improved a form of memory enough that they performed like people in their 20s, a new study found.

Laughter really could be the best medicine when it comes to brain surgery. Neuroscientists at Emory University School of Medicine used electrical stimulation to activate a focal pathway in the brain and trigger laughter, which is immediately followed by a sense of calm and contentment. The technique was used while conducting diagnostic monitoring for seizure diagnosis on an epilepsy patient, with the effects later used to successfully undergo awake brain surgery on the same patient.

38 new genes have been implicated in hearing loss. One of the genes, SPNS2, has been linked to childhood deafness.

Increased kynurenic acid production has been implicated in the pathology of schizophrenia. The findings provide a new target for cell-specific treatments that help reduce the production of kynurenic acid and reduce symptoms of schizophrenia.

Scientists have pinpointed a group of cells in the brain whose activity could help explain the ability to share another’s pain.

Imbalanced communication between the hippocampus and amygdala may lead to the inability to distinguish between negative memories that have overlapping features. The findings could provide new treatment options for those with PTSD.

Finally this week, a new study reports that music synchronizes brainwaves across listeners with strong effects of repetition, familiarity and training.

Weekly Neuroscience Update

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How well-connected a particular brain network is, and how successfully memories are formed, may determine which patients with post-traumatic stress disorder benefit from behavioral therapy, researchers have found.

A new paper discusses the potential of deep brain stimulation in the treatment of Parkinson’s disease, OCD, Tourette syndrome and other disorders.

Reduced blood capillaries in the back of the eye may be a new, noninvasive way to diagnose early cognitive impairment, the precursor to Alzheimer’s disease in which individuals become forgetful, reports a newly published study.

Animal-assisted therapy can foster social competence in patients with brain injuries and increase their emotional involvement during therapy. 

CGRP, a protein associated with migraine pain, appears to act differently between sexes. Researchers say a female-specific mechanism of downstream CGRP receptor activation is likely to contribute to the higher prevalence of migraine in women.

A new model sheds light on the evolutionary origins of empathy and other associated phenomena. 

A team of scientists has shown that when deep-brain stimulation is applied to a specific brain region, it improves patients’ cognitive control over their behavior by increasing the power of a specific low-frequency brain rhythm in their prefrontal cortex.

Researchers have increased understanding of how computing technology could be used to help people with depression remember happy memories.

A study has found that childhood trauma is linked to abnormal connectivity in the brain in adults with major depressive disorder (MDD). The paper, published this week in Proceedings of the National Academy of Sciences (PNAS), is the first data-driven study to show symptom-specific, system-level changes in brain network connectivity in MDD.

Finally this week, the findings of an EEG study on two-month-old babies reveal the impact of maternal stress on early neurodevelopment.

Weekly Neuroscience Update

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Much like opaque filters we apply to pictures on social media, the vibrancy of our memories dims and fades over time. The image reflects 12 levels of visual salience, or vibrancy, used to rate how memories fade. The image is credited to Psychological Science.

Low-level visual information fades in memory over time. However, negative emotion increases subjective memory vividness.

Musical training produces lasting improvements to a cognitive mechanism that helps individuals be more attentive and less likely to be distracted by irrelevant stimuli while performing demanding tasks.

Neurobiologists have studied the formation of inhibitory synapses, a complex process that occurs when the brain adapts. 

The synesthesia effect of being able to ‘hear’ silent movements may depend upon disinhibition of signaling between the visual and auditory brain regions. A new study found musicians are more likely to experience the ‘visual ear’ phenomena than those with no musical training.

Using OCT angiography to quantify capillary changes in the back of the eye can help in the detection, and monitor the progression, of Alzheimer’s disease.

Polygenetic risk scores calculated from adults can be used to identify children and adolescents who may be at greater risk of developing depression, even before clinical symptoms have emerged.

An uncommon variant of the PDE11A gene impacts both quality and duration of sleep. 

Scientists have discovered the key brain region for navigating well-known places, helping explain why brain damage seen in early stages of Alzheimer’s disease can cause such severe disorientation.

Finally this week, a team of researchers has found what they describe as a link between the “locus of control” in adolescents and their use of tobacco and alcohol.

Weekly Neuroscience Update

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Robotic body surrogates can help people with profound motor deficits interact with the world. Here, Henry Evans, a California man who helped Georgia Tech researchers with improvements to a web-based interface, uses the robot to shave himself.  

People with profound motor deficits reported an improved quality of life while using robotic body surrogates.

A new study reports babies’ brains are sensitive to different emotional tones they hear in voices. Researchers suggest maternal interactions may help to shape the same brain region adults use for emotional processing.

Researchers are finding new evidence that exercise — even low-intensity, casual physical activity — can boost brain health in the short- and long-term.

The brain chemical serotonin, a neurotransmitter is long known for its role in passing signals between neurons in the brain, can also regulate expression of genes within neurons in an unexpected way, according to research conducted by neuroscientists at the Icahn School of Medicine at Mount Sinai and published on March 13 in the journal Nature.

New patterns of brain aging across the human lifespan have been revealed by scientists analysing microstructural changes in the brain’s white matter.

According to researchers, there is an optimum amount of dopamine that should be present within the brain. This optimum amount can help improve cognitive performance on tasks, researchers report.

Oxford University scientists have discovered a brain process common to sleep and aging in research that could pave the way for new treatments for insomnia.

Finally this week, a new review, which appears in The BMJ journal, examines the benefits of non-invasive brain stimulation for treating major depression and finds that the technique is a valid alternative to existing treatments.

How Experience Shapes Your Brain #BrainAwarenessWeek

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Early experiences affect the development of brain architecture, which provides the foundation for all future learning, behaviour, and health.

Brains are built over time, from the bottom up.

The basic architecture of the brain is constructed through a process that begins early in life and continues into adulthood.

Simpler circuits come first and more complex brain circuits build on them later.

Brain architecture is comprised of billions of connections between individual neurons across different areas of the brain.

These connections enable lightning-fast communication among neurons that specialise in different kinds of brain functions. The early years are the most active period for establishing neural connections, but new connections can form throughout life and unused connections continue to be pruned.

The interactions of genes and experience shape the developing brain.

Genes provide the basic blueprint, but experiences influence how or whether genes are expressed. Together, they shape the quality of brain architecture and establish either a sturdy or a fragile foundation for all of the learning, health, and behaviour that follow.

Although genes provide the blueprint for the formation of brain circuits, these circuits are reinforced by repeated use.

A major ingredient in this developmental process is the interaction between children and their parents and other caregivers in the family or community.

In the absence of responsive caregiving—or if responses are unreliable or inappropriate—the brain’s architecture does not form as expected, which can lead to disparities in learning and behavior.

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It is easier and less costly to form strong brain circuits during the early years than it is to intervene or “fix” them later.

Cognitive, emotional, and social capacities are inextricably intertwined throughout the life course.

The brain is a highly integrated organ and its multiple functions operate in coordination with one another. Emotional well-being and social competence provide a strong foundation for emerging cognitive abilities, and together they are the bricks and mortar of brain architecture.

Adapted from The Center on the Developing Child at Harvard University. 

Center on the Developing Child at Harvard University

Weekly Neuroscience Update

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NIH scientists present a new method for combining measures of brain activity (left) and glucose consumption (right) to study regional specialization and to better understand the effects of alcohol on the human brain.

Assessing the patterns of energy use and neuronal activity simultaneously in the human brain improves our understanding of how alcohol affects the brain, according to new research by scientists at the National Institutes of Health.

A new study reports teens with high levels of depression display poorer working memory in tests than those with low symptoms.

Eating a diet rich in fruits and vegetables, moderate in nuts, fish and alcohol and low in meat and full-fat dairy is associated with better cognitive performance in middle age, according to researchers.

A team of researchers has identified, for the first time, the cell types, areas and biological processes in the brain that mediate the genetic risk of insomnia.

Scientists report EEG technology has the ability to study activity of areas deep inside the brain, such as the thalamus and nucleus accumbens. The findings will help shed new light on disorders that affect these brain regions, such as Parkinson’s disease and OCD.

Researchers have identified a pathway near the midbrain where neural messages for taste and pain converge, a new study reports.

A new study reveals how blood vessels help protect the brain during inflammation. The findings could help in the development of new treatments for neurodegenerative and autoimmune diseases.

Choosing to forget something might take more mental effort than trying to remember it, scientists have discovered through neuroimaging.

According to researchers, keeping both physically and mentally active during middle age can significantly reduce the risk of developing dementia during old age. The study found women who participated in mental activities were 46% less likely to develop dementia, and those who were physically active at a 52% reduced risk.

Finally this week, a new study reveals women have higher activation in sensory areas of the brain associated with pain compared to males when witnessing another person suffering.