PINK1, a gene associated with Parkinson’s disease, is not just responsible for the premature death of dopaminergic neurons, it also plays a key role in the neurogenesis of dopamine neurons throughout life.
Category: neuroscience – Page 746
A novel marker of adult human neural stem cells discovered
Should interest those into links on aging/longevity and neuroscience.
The mammalian center for learning and memory, hippocampus, has a remarkable capacity to generate new neurons throughout life. Newborn neurons are produced by neural stem cells (NSCs) and they are crucial for forming neural circuits required for learning and memory, and mood control. During aging, the number of NSCs declines, leading to decreased neurogenesis and age-associated cognitive decline, anxiety, and depression. Thus, identifying the core molecular machinery responsible for NSC preservation is of fundamental importance if we are to use neurogenesis to halt or reverse hippocampal age-related pathology.
While there are increasing number of tools available to study NSCs and neurogenesis in mouse models, one of the major hurdles in exploring this fundamental biological process in the human brain is the lack of specific NSCs markers amenable for advanced imaging and in vivo analysis. A team of researchers led by Dr. Mirjana Maletić-Savatić, associate professor at Baylor College of Medicine and investigator at the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, and Dr. Louis Manganas, associate professor at the Stony Brook University, decided to tackle this problem in a rather unusual way. They reasoned that if they could find proteins that are present on the surface of NSCs, then they could eventually make agents to “see” NSCs in the human brain.
“The ultimate goal of our research is to maintain neurogenesis throughout life at the same level as it is in the young brains, to prevent the decline in our cognitive capabilities and reduce the tendency towards mood disorders such as depression, as we age. To do that, however, we first need to better understand this elusive, yet fundamental process in humans. However, we do not have the tools to study this process in live humans and all the knowledge we have gathered so far comes from analyses of the postmortem brains. And we cannot develop tools to detect this process in people because existing NSC markers are present within cells and unreachable for in vivo visualization,” Maletić-Savatić said. “So, in collaboration with our colleagues from New York and Spain, we undertook this study to find surface markers and then develop tools such as ligands for positron emission tomography (PET) to visualize them using advanced real-time in vivo brain imaging.”
Reverse engineering the cognitive brain
Circa 2013
One of the greatest aspirations of the human mind has been to realize machines that surpass its cognitive intelligence. The rapid expansion in computing power, about to exceed the equivalent of the human brain, has yet to produce such a machine. The article by Neftci et al. in PNAS (1) offers a refreshing and humbling reminder that the brain’s cognition does not arise from exacting digital precision in high-performance computing, but rather emerges from an extremely efficient and resilient collective form of computation extending over very large ensembles of sluggish, imprecise, and unreliable analog components. This observation, first made by John von Neumann in his final opus (2), continues to challenge scientists and engineers several decades later in figuring and reproducing the mechanisms underlying brain-like forms of cognitive computing.
Related developments are currently unfolding in collaborative initiatives engaging scientists and engineers, on a grander scale, in advancing neuroscience toward understanding the brain. In parallel with the Human Brain Project in Europe, the Brain Research through Advancing Innovative Neurotechnologies Initiative promises groundbreaking advances in enabling tools for revolutionizing neuroscience by developing nanotechnology to probe brain function at greatly increased spatial and temporal detail. Engineers are poised to contribute even further in revolutionizing such developments in neuroscience. In this regard it is helpful to relate the inquisitive nature of science—analysis—to the constructive power of engineering, synthesis.
New Genetic Mutation Discovered in People with Schizophrenia
The research team, led by Todd Lencz, PhD, with Itsik Pe’er, PhD, Tom Maniatis, PhD, and Erin Flaherty, PhD, of Columbia University, carried out a genetic study identifying a single letter change in the DNA code in the PCDHA3 gene that is associated with schizophrenia. The affected gene makes a type of protein called a protocadherin, which generates a cell surface “barcode” required for neurons to recognize, and communicate with, other neurons. They found that the PCDHA3 variant blocks this normal protocadherin function.
The discovery was made possible by the special genetic characteristics of the samples studied by Lencz’s team—patients with schizophrenia and healthy volunteers drawn from the Ashkenazi Jewish population. The Ashkenazi Jewish population represents an important population for study based on its unique history. Just a few hundred individuals who migrated to Eastern Europe less than 1000 years ago are the ancestors of nearly 10 million Ashkenazi Jews today. This lineage, combined with a tradition of marriage within the community, has resulted in a more uniform genetic background in which to identify disease-related variants.
“In addition to our primary findings regarding PCDHA3 and related genes, we were able— due to the unique characteristics of the Ashkenazi population—to replicate several prior findings in schizophrenia despite relatively small sample sizes,” said Lencz, professor in the Institute of Behavioral Science at the Feinstein Institutes. “In our study, we demonstrated this population represents a smart, cost-effective strategy for identifying disease-related genes. Our findings allow us to zero in on a novel aspect of brain development and function in our quest to develop new treatments for schizophrenia.”
There are no autism-specific genes, just brain genes
It is well established that rare, damaging genetic variants with strong effects contribute to autism. Although individually rare, these variants are collectively common: Clinical genetic testing identifies them in at least 25 percent of autistic people. Studies of these variants have implicated more than 100 genes — and counting — in autism.
Identifying these genes is important — not only for clinical care, but also for advancing our understanding of the neural circuits and processes involved in autism or in its core traits. It creates the opportunity to develop therapies targeted to specific molecular diagnoses. And as we learn more about these genes and the consequences of variants that disrupt their function, we have the potential to better understand the mechanisms underlying cases of autism in which a definitive genetic diagnosis cannot yet be made.
But the genetic findings in people with autism are not unique; deleterious variants in the same genes are also implicated in other neurodevelopmental conditions, such as intellectual disability, epilepsy, attention deficit hyperactivity disorder and schizophrenia. Specific genes and variants do not map neatly onto categorical clinical diagnoses or the core cognitive and behavioral traits that define them. In fact, there is not yet a single example of a gene that, when mutated, increases the likelihood of autism but not of other neurodevelopmental conditions.
TAFFD’s AFRICA VIRTUAL TOWN HALL MEETING
Join the Transdisciplinary Agora for Future Discussions, Inc. — TAFFD’s.
A bi-weekly virtual town hall-like show presenting in-depth discussions on issues connected to African advancement in the 21st century ranging from science, technology, … See More.
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Mission.
Creating a space for discussions on ideas and issues related to the African condition, and develop a suitable narrative through multidimensional approaches to drive progress in Africa towards a sustainable and more prosperous future.
Vision.
Building from the present and critically reconstructed African past for a greater, highly advanced, cosmopolitan, peaceful, and prosperous future African civilization through meaningful and fruitful discourse and action.
Holding: TAFFD’s Africa.
Reading Minds With Ultrasound
Summary: Focused ultrasound allowed researchers to record and monitor brain activity in a non-invasive way. The technology allowed the researchers to predict movement.
Source: CalTech.
What is happening in your brain as you are scrolling through this page? In other words, which areas of your brain are active, which neurons are talking to which others, and what signals are they sending to your muscles?
Neuroscientists identify brain circuit motifs that support short-term memory
Humans have the innate ability to store important information in their mind for short periods of time, a capability known as short-term memory. Over the past few decades, numerous neuroscientists have tried to understand how neural circuits store short-term memories, as this could lead to approaches to assist individuals whose memory is failing and help to devise memory enhancing interventions.
Researchers at Stanford and the Janelia Research Campus, Howard Hughes Medical Institute have recently identified neural circuit motifs involved in how humans store short-term memories. Their findings, published in Nature Neuroscience, suggest that memory-related neural circuits contain recurrently connected modules that independently maintain selective and continuous activity.
“Short-term memories are of approximately 10 seconds or so, for example, if you needed to remember a phone number while you looked for a pen to write the number,” Kayvon Daie, one of the researchers who carried out the study, told Medical Xpress. “Individual neurons, however, are very forgetful, as they can only remember their inputs for about 10 milliseconds. It has been hypothesized that if two forgetful neurons were connected to each other, they could continuously remind each other of what they were supposed to remember so that the circuit can now hold information for many seconds.”
Towards the end of deep learning and the beginning of AGI
How recent research points the way towards defeating adversarial examples and achieving a more resilient, consistent and flexible A.I.
How recent neuroscience research points the way towards defeating adversarial examples and achieving a more resilient, consistent and flexible form of artificial intelligence.