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Category: neuroscience – Page 165

Study finds language-processing difficulties are an indicator — more so than memory loss — of amnestic mild cognitive impairment.

Individuals with mild cognitive impairment, especially of the “amnestic subtype” (aMCI), are at increased risk for dementia due to Alzheimer’s disease relative to cognitively healthy older adults. Now, a study co-authored by researchers from MIT, Cornell University, and Massachusetts General Hospital has identified a key deficit in people with aMCI, which relates to producing complex language.

This deficit is independent of the memory deficit that characterizes this group and may provide an additional “cognitive biomarker” to aid in early detection — the time when treatments, as they continue to be developed, are likely to be most effective.

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A new study presents findings from the characterization of the individual roles of the motor neurons that control head movement in Drosophila melanogaster.

Despite the pivotal role of motor neurons in movement, how a single motor neuron contributes to control during movement remains unclear. Measuring the activity of individual neurons in moving animals has proven to be experimentally difficult.

However, advances have made it possible for researchers to manipulate single motor neurons in fruit flies as the insects move freely. A new study presents the findings from the characterization of the individual roles of the motor neurons that control head movement in Drosophila melanogaster.

The findings were published in Nature in the paper, “Motor neurons generate pose-targeted movements via proprioceptive sculpting.”

Continue reading “Single Motor Neurons Analyzed in 3D in a Moving Fly Body” | >

We can test the cognitive abilities of octopuses in the lab. In our EthoS laboratory, we are currently working on the memory and future planning abilities of the common octopus. They are complex animals to study, because of their astonishing abilities.

Their incredible strength allows them to easily destroy our lab tools: be careful with underwater cameras, they can open the waterproof box to drown them! And because octopuses are boneless, they can easily escape their tanks through the smallest of openings. They are also extremely curious and will spend their time catching hands, nets or any other object introduced to their tank. From there, it is up to them to decide when to release their catch.

The opening of jars, while impressive and often used to illustrate octopus intelligence, is not their most remarkable ability. This is mostly a matter of dexterity and gripping, and octopuses are quite slow when executing this task: even when over-trained, an octopus always takes more than a minute to open a jar. A better example of their impressive intelligence is their ability to manipulate an L-shaped object so it can pass through a small square opening in a wall.

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Results of DNA studies also seem to confirm the idea that optimism is an effective tool for slowing down cellular aging, of which telomere shortening is a biomarker. (Telomeres are the protective caps at the end of our chromosomes.) This research is still in progress, but the early results are informative. In 2012, Elizabeth Blackburn, who three years earlier shared a Nobel Prize for her work in discovering the enzyme that replenishes the telomere, and Elissa Epel at the University of California at San Francisco, in collaboration with other institutions, identified a correlation between pessimism and accelerated telomere shortening in a group of postmenopausal women. A pessimistic attitude, they found, may indeed be associated with shorter telomeres. Studies are moving toward larger sample sizes, but it already seems apparent that optimism and pessimism play a significant role in our health as well as in the rate of cellular senescence. More recently, in 2021, Harvard University scientists, in collaboration with Boston University and the Ospedale Maggiore in Milan, Italy, observed the telomeres of 490 elderly men in the Normative Health Study on U.S. veterans. Subjects with strongly pessimistic attitudes were associated with shorter telomeres — a further encouraging finding in the study of those mechanisms that make optimism and pessimism biologically relevant.

Optimism is thought to be genetically determined for only 25 percent of the population. For the rest, it’s the result of our social relationships or deliberate efforts to learn more positive thinking. In an interview with Jane Brody for the New York Times, Rozanski explained that “our way of thinking is habitual, unaware, so the first step is to learn to control ourselves when negative thoughts assail us and commit ourselves to change the way we look at things. We must recognize that our way of thinking is not necessarily the only way of looking at a situation. This thought alone can lower the toxic effect of negativity.” For Rozanski, optimism, like a muscle, can be trained to become stronger through positivity and gratitude, in order to replace an irrational negative thought with a positive and more reasonable one.

While the exact mechanisms remain under investigation, a growing body of research suggests that optimism plays a significant role in promoting both physical and mental well-being. Cultivating a positive outlook, then, can be a powerful tool for fostering resilience, managing stress, and potentially even enhancing longevity. By adopting practices that nurture optimism, we can empower ourselves to navigate life’s challenges with greater strength and live healthier, happier lives.

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A novel approach in the field of Alzheimer’s research is emerging that could potentially transform how we tackle this debilitating disease. Recent studies have revealed a paradigm shift in understanding Alzheimer’s pathology, emphasizing the importance of targeting the early-stage aggregation of the pathogenic amyloid beta (A-beta) protein, specifically focusing on its soluble oligomeric form.

Over the past three decades, conventional treatments for Alzheimer’s have largely been ineffective, primarily due to their focus on combating the fibrillar form of A-beta. However, emerging research suggests that it is the soluble oligomeric form of A-beta that poses the greatest threat to neuronal health, leading to cognitive decline and neurotoxicity.

A recent breakthrough in Alzheimer’s treatment has come from the development of an antibody capable of recognizing both oligomeric and fibrillar forms of A-beta, offering newfound hope to the field. This innovative therapy has demonstrated promising results in delaying disease progression by up to 36% in individuals with early-to-mild cognitive impairment.

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Human brains preserve in diverse environments for at least 12 000 years—new research in Proceedings B this week: https://royalsocietypublishing.org/doi/10.1098/rspb.2023.

Soft tissue preservation in the geological record is relatively rare, and when an archaeologist digs a human skull out of the…

The brain is thought to be among the first human organs to decompose after death. The discovery of brains preserved in the archaeological record is therefore regarded as unusual. Although mechanisms such as dehydration, freezing, saponification, and tanning are known to allow for the preservation of the brain on short time scales in association with other soft tissues (≲4000 years), discoveries of older brains, especially in the absence of other soft tissues, are rare. Here, we collated an archive of more than 4,400 human brains preserved in the archaeological record across approximately 12 000 years, more than 1,300 of which constitute the only soft tissue preserved amongst otherwise skeletonized remains. We found that brains of this type persist on time scales exceeding those preserved by other means, which suggests an unknown mechanism may be responsible for preservation particular to the central nervous system. The untapped archive of preserved ancient brains represents an opportunity for bioarchaeological studies of human evolution, health and disease.

Since the mid-17th century, more than 4,400 human brains have been unearthed from the last 12 000 years of the archaeological record, over 1,300 of which are preserved among otherwise skeletonized remains. Despite this volume of finds, the perception remains that preserved brains represent ‘unique’ or ‘extremely rare’ discoveries [1]. Human soft tissues are understood to persist through time by well-characterized mechanisms of preservation such as dehydration, freezing and tanning, brought about by anthropogenic (i.e. the result of deliberate human intervention) or naturally occurring factors. Thus, it is not surprising that the brain endures alongside other internal organs where there is extensive soft tissue preservation.

Continue reading “Human brains preserve in diverse environments for at least 12 000 years” | >

Studies of brain network connectivity improved understanding on brain changes and adaptation in response to different pathologies. Synaptic plasticity, the ability of neurons to modify their connections, is involved in brain network remodeling following different types of brain damage (e.g., vascular, neurodegenerative, inflammatory). Although synaptic plasticity mechanisms have been extensively elucidated, how neural plasticity can shape network organization is far from being completely understood. Similarities existing between synaptic plasticity and principles governing brain network organization could be helpful to define brain network properties and reorganization profiles after damage. In this review, we discuss how different forms of synaptic plasticity, including homeostatic and anti-homeostatic mechanisms, could be directly involved in generating specific brain network characteristics. We propose that long-term potentiation could represent the neurophysiological basis for the formation of highly connected nodes (hubs). Conversely, homeostatic plasticity may contribute to stabilize network activity preventing poor and excessive connectivity in the peripheral nodes. In addition, synaptic plasticity dysfunction may drive brain network disruption in neuropsychiatric conditions such as Alzheimer’s disease and schizophrenia. Optimal network architecture, characterized by efficient information processing and resilience, and reorganization after damage strictly depend on the balance between these forms of plasticity.

Keywords: brain networks, connectivity, synaptic plasticity, Alzheimer’s disease (AD), schizophrenia, long-term potentiation (LTP), synaptic scaling, resting state functional MRI (rs-fMRI)

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Our H+ friend Rob Wilkes alerted me to this today!

March 20 (Reuters) — Elon Musk’s brain-chip startup Neuralink livestreamed on Wednesday its first patient implanted with a chip using his mind to play online chess.

Noland Arbaugh, the 29-year-old patient who was paralyzed below the shoulder after a diving accident, played chess on his laptop and moved the cursor using the Neuralink device. The implant seeks to enable people to control a computer cursor or keyboard using only their thoughts.

Arbaugh had received an implant from the company in January and could control a computer mouse using his thoughts, Musk said last month.

Continue reading “Musk’s Neuralink shows first brain-chip patient playing online chess” | >