Tag Archives: Imaging

A new and versatile imaging technique enables researchers to trace the trajectories of whole nerve cells and provides extensive insights into the structure of neuronal networks.

Lesions caused by traumatic brain damage, stroke and functional decline due to aging processes can disrupt the complex cellular network that constitutes the central nervous system, and lead to chronic pathologies, such as dementia, epilepsy and deleterious metabolic perturbations. But exactly how this happens is unknown. Researchers have now refined a novel imaging technique that allows them to visualize and monitor these structural alterations in neuronal networks. The new findings appear in the journal Nature Methods.

Nerve cells transmit electrical impulses over long distances along fibrous connections called axons, which extend from the cell body where the nucleus resides. Indeed, many neurons in the brainstem possess axons that project as far as the base of the spinal column. Thus damage to these axons can affect the function of parts of the central nervous system that are remote from the actual site of injury. The new imaging method is based on a clearing-and-shrinkage procedure that can render whole organs and organisms transparent, making – for instance – the full length of the rodent spinal cord accessible to optical imaging. Moreover, the technique is applicable down to the level of individual cells, which are labeled with fluorescent protein tags and can be visualized under the microscope by irradiating them with visible light. This enables researchers to map complex neuronal networks in rodents in 3D, a significant step in revealing the enigma behind the human brain.

Because essentially all cell types – including immune cells and tumor cells – can be specifically labeled with the aid of appropriate fluorescent markers or antibodies, the new method can be employed in a broad range of biomedical settings. Furthermore, the images obtained can be archived in a database and made available to other researchers, which should help reduce unnecessary duplication of studies.

Paper: “Shrinkage-mediated imaging of entire organs and organisms using uDISCO”

Reprinted from materials provided by LMU Medical Center.

The AgedBrainSYSBIO consortium, a four-year project on brain ageing funded by the European Commission under the Health Cooperation Programme of the 7th Framework Programme, is hosting a public workshop, Normal and pathological brain ageing: from systems biology to the clinic.

The workshop, to be held on October 19, 2016, at the Imagine Institute in Paris, will bring together clinicians, biologists, bioinformaticians and statisticians to present the latest advances in the field.

To view the preliminary programme and register for the workshop, visit the AgedBrainSYSBIO website.

Ten international JPND working groups recommended for funding

The EU Joint Programme – Neurodegenerative Disease Research (JPND) has released the results of a “rapid-action” call to support working groups of leading scientists to bring forward novel approaches that will enhance the use of brain imaging for neurodegenerative disease research.

Ten working groups have been recommended for funding to address the methodological challenges facing different imaging modalities, among them MRI, PET, ultrasound, MEG and EEG, as well as multimodal approaches. The working groups cover a range of neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, Frontotemporal dementia and Huntington’s disease.

“Brain imaging has made enormous progress in recent years and is currently one of the most promising avenues in neurodegenerative disease research,” said Professor Thomas Gasser, Chair of the JPND Scientific Advisory Board. “If we can solve the challenges in the field, brain imaging could rapidly lead to faster and better diagnoses as well as a deeper understanding of the fundamental aspects and mechanisms of neurodegeneration.”

Although imaging techniques have brought about a dramatic improvement in the understanding of neurodegenerative diseases, there remain a number of significant challenges in the field. These include the execution of multi-centre clinical trials of an unprecedented scale, data transfer across imaging centres and the use of imaging for diagnostics and for measuring clinical outcomes.

To address these questions, on January 8, 2016, JPND launched a call for community-led working groups on harmonisation and alignment in brain imaging methods. The proposals recommended for funding are for top scientists to come together and propose, through ‘best practice’ guidelines and/or methodological frameworks, how to overcome key barriers to the use of imaging in neurodegenerative disease research.

The call attracted proposals with partners from across Europe and beyond, including Asia, Australia, North America and South America. A notable number of groups based in the United States were involved in responses to the call. Funding decisions were based upon scientific evaluation and recommendations to sponsor countries by a JPND peer review panel.

“This call perfectly embodies JPND’s mission and objectives,” said Professor Philippe Amouyel, Chair of the JPND Management Board. “The purpose of JPND is to strengthen coordination and collaboration in neurodegenerative disease research across different countries. We want to ensure that research efforts are not duplicated, to build consensus and to accelerate a path toward a cure that works. This call convenes groups of leading experts to hammer out the hard questions, including the challenges of interoperability and shared and open data, to allow researchers to more rapidly and more fully exploit imaging techniques going forward.”

Each working group is expected to run for a maximum of 9 months. The outputs of the working groups are to be produced by the end of the funding period, and will be published on the JPND website and used for further JPND actions. In addition, a common workshop will be organised to bring together and present the recommendations of each working group, encouraging the further exchange of ideas and wider dissemination to different stakeholder groups.

For more information on the working groups recommended for funding, click here.

New research shows for the first time that PET scans can track the progressive stages of Alzheimer’s disease in cognitively normal adults, a key advance in the early diagnosis and staging of the neurodegenerative disorder.

In the process, the scientists also obtained important clues about two Alzheimer’s-linked proteins – tau and beta-amyloid – and how they relate to each other.

The findings, published in the journal Neuron, come from positron emission tomography (PET) of 53 adults. Five were young adults aged 20-26, 33 were cognitively healthy adults aged 64-90 and 15 were patients aged 53-77 who had been diagnosed with probable Alzheimer’s dementia.

PET scans are used to detect early signs of disease by looking at cellular-level changes in organs and tissue. The results of the scans in this study paralleled Braak neuropathological stages, which range from one to six, describing the degree of tau protein accumulation in the brain.

The findings also shed light on the nature of tau and amyloid protein deposits in the aging brain. For many years, the accumulation of beta amyloid plaques was considered the primary culprit in Alzheimer’s disease. Over the past decade, however, tau, a microtubule protein important in maintaining the structure of neurons, has emerged as a major player. When the tau protein gets tangled and twisted, its ability to support synaptic connections becomes impaired.

While a number of symptoms exist that signal Alzheimer’s disease, a definitive diagnosis has been possible only through an examination of the brain after the patient has died. The availability of amyloid imaging for the past decade has improved this situation, but how Alzheimer’s developed as a result of amyloid remains a mystery. Studies done in autopsies linked the development of symptoms to the deposition of the tau protein.

Through the PET scans, the researchers confirmed that with advancing age, tau protein accumulated in the medial temporal lobe — home to the hippocampus and the memory center of the brain.

The study revealed that higher levels of tau in the medial temporal lobe was associated with greater declines in episodic memory, the type of memory used to code new information. The researchers tested episodic memory by asking subjects to recall a list of words viewed 20 minutes earlier.

One question yet to be answered is why so many people have tau in their medial temporal lobe yet never go on to develop Alzheimer’s. Likewise, adults may have beta amyloid in their brains and yet be cognitively healthy.

While higher levels of tau in the medial temporal lobe was linked to more problems with episodic memory, it was when tau spread outside this region to other parts of the brain, such as the neocortex, that researchers saw more serious declines in global cognitive function. Significantly, they found that tau’s spread outside the medial temporal lobe was connected to the presence of amyloid plaques in the brain.

What the study does indicate is that tau imaging could become an important tool in helping to develop therapeutic approaches that target the correct protein — either amyloid or tau — depending on the disease stage.

Source: Sarah Yang, UC Berkeley

A digital map of the ageing brain could aid the diagnosis of Alzheimer’s disease and other neurodegenerative disorders in older people, a study suggests.

The atlas created using images from MRI scans of older people could aid diagnosis by comparing the patients’ scans with a detailed map of the healthy ageing brain.

Most existing MRI atlases are based on the brains of young and middle-aged people, which don’t reflect the normal changes that take place in the brain as we age, the team says. Researchers at the University of Edinburgh constructed a detailed atlas of the human brain using MRI scans from more than 130 healthy people aged 60 or over.

The team used their atlas to study brain scans taken of normal older subjects and those who had been diagnosed with Alzheimer’s disease. The atlas was able to pinpoint changes in patients’ brain structure that can be an underlying sign of the condition, researchers say.

The study is published in the journal PLOS ONE.

Dr David Alexander Dickie, of The University of Edinburgh’s Brain Research Imaging Centre and SINAPSE, who was first author of the study, said: “We’re absolutely delighted with these preliminary results and that our brain MRI atlases may be used to support earlier diagnoses of diseases such as Alzheimer’s. Earlier diagnoses are currently our strongest defence against these devastating diseases and, while our work is preliminary and ongoing, digital brain atlases are likely to be at the core of this defence.”

Source: University of Edinburgh

Researchers in Oxford, UK have discovered a specific network in the brain that is the first to degenerate with age and also the most vulnerable spot for the development of schizophrenia and Alzheimer’s disease.

The study, published in the journal Proceedings of the National Academy of Sciences, used magnetic resonance imaging (MRI) scans to analyze changes in the brain structures of 484 healthy participants, ages eight to 85 years.

“Our results show that the same specific parts of the brain not only develop more slowly, but also degenerate faster than other parts,” said researcher Dr. Gwenaëlle Douaud, at Oxford University’s Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB).

“These complex regions, which combine information coming from various senses, seem to be more vulnerable than the rest of the brain to both schizophrenia and Alzheimer’s, even though these two diseases have different origins and appear at very different, almost opposite, times of life.”
The researchers used a “data-driven” approach for the study. Instead of looking for a particular pattern of brain change over the lifespan in a specific location of the brain, they analyzed all the imaging data to see what patterns appeared.

http://www.presstv.ir/detail/2014/11/29/387989/brains-weak-spot-for-dementia-found/

http://psychcentral.com/news/2014/11/28/vulnerable-brain-spot-tied-to-schizophrenia-alzheimers/77873.html