Posts tagged neuroimaging

A multicenter research team led by Cedars-Sinai neurologist Nancy Sicotte, MD, an expert in multiple sclerosis and state-of-the-art imaging techniques, used a new, automated technique to identify shrinkage of a mood-regulating brain structure in a large sample of women with MS who also have a certain type of depression.

In the study, women with MS and symptoms of “depressive affect” – such as depressed mood and loss of interest – were found to have reduced size of the right hippocampus. The left hippocampus remained unchanged, and other types of depression – such as vegetative depression, which can bring about extreme fatigue – did not correlate with hippocampal size reduction, according to an article featured on the cover of the January 2014 issue of Human Brain Mapping.

The research supports earlier studies suggesting that the hippocampus may contribute to the high frequency of depression in multiple sclerosis. It also shows that a computerized imaging technique called automated surface mesh modeling can readily detect thickness changes in subregions of the hippocampus. This previously required a labor-intensive manual analysis of MRI images.

Sicotte, the article’s senior author, and others have previously found evidence of tissue loss in the hippocampus, but the changes could only be documented in manual tracings of a series of special high-resolution MRI images. The new approach can use more easily obtainable MRI scans and it automates the brain mapping process.

“Patients with medical disorders – and especially those with inflammatory diseases such as MS – often suffer from depression, which can cause fatigue. But not all fatigue is caused by depression. We believe that while fatigue and depression often co-occur in patients with MS, they may be brought about by different biological mechanisms. Our studies are designed to help us better understand how MS-related depression differs from other types, improve diagnostic imaging systems to make them more widely available and efficient, and create better, more individualized treatments for our patients,” said Sicotte, director of Cedars-Sinai’s Multiple Sclerosis Program and the Neurology Residency Program. She received a $506,000 grant from the National Multiple Sclerosis Society last year to continue this research.

(Source: newswise.com)

Assessing structural and functional changes in the brain may predict future memory performance in healthy children and adolescents, according to a study appearing January 29 in The Journal of Neuroscience. The findings shed new light on cognitive development and suggest MRI and other tools may one day help identify children at risk for developmental challenges earlier than current testing methods allow.

Working memory capacity — the ability to hold onto information for a short period of time — is one of the strongest predictors of future achievements in math and reading. While previous studies showed that MRI could predict current working memory performance in children, scientists were unsure if MRI could predict their future cognitive capacity.

In the current study, Henrik Ullman, Rita Almeida, PhD, and Torkel Klingberg, MD, PhD, at the Karolinska Institutet in Sweden evaluated the cognitive abilities of a group of healthy children and adolescents and measured each child’s brain structure and function using MRI. Based on the MRI data collected during this initial testing, the researchers found they could predict the children’s working memory performance two years later, a prediction that was not possible using the cognitive tests.

“Our results suggest that future cognitive development can be predicted from anatomical and functional information offered by MRI above and beyond that currently achieved by cognitive tests,” said Ullman, the lead author of the study. “This has wide implications for understanding the neural mechanisms of cognitive development.”

The scientists recruited 62 children and adolescents between the ages of 6 and 20 years to the lab, where they completed working memory and reasoning tests. They also received multiple MRI scans to assess brain structure and changes in brain activity as they performed a working memory task. Two years later, the group returned to the lab to perform the same cognitive tests.

Using a statistical model, the researchers evaluated whether MRI data obtained during the initial tests correlated with the children’s working memory performance during the follow-up visit. They found that while brain activity in the frontal cortex correlated with children’s working memory at the time of the initial tests, activity in the basal ganglia and thalamus predicted how well children scored on the working memory tests two years later.

“This study is another contribution to the growing body of neuroimaging research that yields insights into unraveling present and predicting future cognitive capacity in development,” said Judy Illes, PhD, a neuroethicist at the University of British Columbia. “However, the appreciation of this important new knowledge is simpler than its application to everyday life. How a child performs today and tomorrow relies on multiple positive and negative life events that cannot be assessed by today’s technology alone.”

(Source: alphagalileo.org)

Infants born prematurely are at elevated risk for cognitive, motor, and behavioral deficits — the severity of which was, until recently, almost impossible to accurately predict in the neonatal period with conventional brain imaging technology. But physicians may now be able to identify the premature infants most at risk for deficits as well as the type of deficit, enabling them to quickly initiate early neuroprotective therapies, by using highly reliable 3-D MRI imaging techniques developed by clinician scientists at The Research Institute at Nationwide Children’s Hospital. The imaging technique also facilitates early and repeatable assessments of these therapies to help clinicians and researchers determine whether neuroprotective treatments are effective in a matter of weeks, instead of the two to five years previously required.

The researchers — experts in brain imaging and anatomy — developed a protocol for using the special imaging technique to study the development of 10 brain tracts in these tiny patients, work published online January 24 in PLOS One. Colorful 3-D images of each tract revealed the connections of the segments to different parts of the brain or the spinal cord. Each of the 10 tracts is important for certain functions and abilities, such as language, movement or vision.

“Developing a reliable and reproducible methodology for studying the premature brain was crucial in order for us to get to the next step: assessing neuroprotective therapies,” said Nehal A. Parikh, DO, principal investigator in the Center for Perinatal Research at Nationwide Children’s and senior author on the paper. “Now that we have this protocol, we can improve the standard of care and evaluate efforts to promote brain health within 8 to 12 weeks of beginning the interventions. That way, we can quickly see what really works.”

The study tested a detailed approach to measuring brain structure in extremely low birth weight infants at term-equivalent age by comparing their diffusion tensor tractography (DTT) scans to those of healthy, full-term newborns. DTT is a special MRI technique that produces 3-D images and is able to detect the brain’s structure and more subtle injuries than earlier forms of the technology.

The research team is the first to confirm differences in the fibrous structure of the 10 tracts between healthy, full-term infant brains and those of premature babies. Although the imaging technology is regularly used in adults, the tiny head size and lack of benchmark measurements in healthy infants meant that the use of DTT in premature infants was previously uncharted territory. With the detailed technique developed by Dr. Parikh’s team, the images can now be reproducibly processed and reliably interpreted.

“This protocol opens the field to far greater use of the methodology for targeting and assessing therapies in these infants,” said Dr. Parikh, who also is an associate professor of pediatrics at The Ohio State University College of Medicine. “We already have studies underway using our DTT segmentation methodology to measure the effectiveness of early neuroprotective interventions, such as the use of breast milk or skin-to-skin contact while premature babies are in intensive care.”

As imaging technology continues to be refined, the goal of targeted therapies based on the specific region of the brain with a delay or injury will become reality, Dr. Parikh predicted.For example, if an infant’s DTT scan indicates an under-developed corticospinal tract — the region of the brain controlling motor ability — physicians could immediately begin proactive physical therapies with the baby instead of waiting until the delay manifests itself. A repeat DTT scan a few months after beginning the therapy could then detect whether the therapy is effectively improving the structure of that brain tract.

“Because cognitive and behavioral deficits cannot be diagnosed until school age, there is an urgent need for robust early prognostic biomarkers,” said Dr. Parikh. “Our work is an important step in this direction and will facilitate early testing of neuroprotective interventions.”

(Source: nationwidechildrens.org)

Researchers from Massachusetts Eye and Ear, Harvard Medical School, Massachusetts Institute of Technology and Massachusetts General Hospital have demonstrated, for the first time, that aspirin intake correlates with halted growth of vestibular schwannomas (also known as acoustic neuromas), a sometimes lethal intracranial tumor that typically causes hearing loss and tinnitus.

Image credit: Stanford School of Medicine/Oghalai Lab

Motivated by experiments in the Molecular Neurotology Laboratory at Mass. Eye and Ear involving human tumor specimens, the researchers performed a retrospective analysis of over 600 people diagnosed with vestibular schwannoma at Mass. Eye and Ear. Their research suggests the potential therapeutic role of aspirin in inhibiting tumor growth and motivates a clinical prospective study to assess efficacy of this well-tolerated anti-inflammatory medication in preventing growth of these intracranial tumors.

“Currently, there are no FDA-approved drug therapies to treat these tumors, which are the most common tumors of the cerebellopontine angle and the fourth most common intracranial tumors,” explains Konstantina Stankovic, M.D., Ph.D., who led the study. “Current options for management of growing vestibular schwannomas include surgery (via craniotomy) or radiation therapy, both of which are associated with potentially serious complications.”

The findings, which are described in the February issue of the journal Otology & Neurotology, were based on a retrospective series of 689 people, 347 of whom were followed with multiple magnetic resonance imaging MRI scans (50.3%). The main outcome measures were patient use of aspirin and rate of vestibular schwannoma growth measured by changes in the largest tumor dimension as noted on serial MRIs. A significant inverse association was found among aspirin users and vestibular schwannoma growth (odds ratio: 0.50, 95 percent confidence interval: 0.29-0.85), which was not confounded by age or gender.

“Our results suggest a potential therapeutic role of aspirin in inhibiting vestibular schwannoma growth,” said Dr. Stankovic, who is an otologic surgeon and researcher at Mass. Eye and Ear, Assistant Professor of Otology and Laryngology, Harvard Medical School (HMS), and member of the faculty of Harvard’s Program in Speech and Hearing Bioscience and Technology.

(Source: masseyeandear.org)

An Auburn University researcher teamed up with the National Institutes of Health to study how brain networks shape an individual’s religious belief, finding that brain interactions were different between religious and non-religious subjects.

Gopikrishna Deshpande, an assistant professor in the Department of Electrical and Computer Engineering in Auburn’s Samuel Ginn College of Engineering, and the NIH researchers recently published their results in the journal, “Brain Connectivity.”

The group found differences in brain interactions that involved the theory of mind, or ToM, brain network, which underlies the ability to relate between one’s personal beliefs, intents and desires with those of others. Individuals with stronger ToM activity were found to be more religious. Deshpande says this supports the hypothesis that development of ToM abilities in humans during evolution may have given rise to religion in human societies.

“Religious belief is a unique human attribute observed across different cultures in the world, even in those cultures which evolved independently, such as Mayans in Central America and aboriginals in Australia,” said Deshpande, who is also a researcher at Auburn’s Magnetic Resonance Imaging Research Center. “This has led scientists to speculate that there must be a biological basis for the evolution of religion in human societies.”

Deshpande and the NIH scientists were following up a study reported in the Proceedings of the National Academy of Sciences, which used functional magnetic resonance imaging, or fMRI, to scan the brains of both self-declared religious and non-religious individuals as they contemplated three psychological dimensions of religious beliefs.

The fMRI – which allows researchers to infer specific brain regions and networks that become active when a person performs a certain mental or physical task – showed that different brain networks were activated by the three psychological dimensions; however, the amount of activation was not different in religious as compared to non-religious subjects.

(Source: wireeagle.auburn.edu)

We use both sides of our brain for speech, a finding by researchers at New York University and NYU Langone Medical Center that alters previous conceptions about neurological activity. The results, which appear in the journal Nature, also offer insights into addressing speech-related inhibitions caused by stroke or injury and lay the groundwork for better rehabilitation methods.

“Our findings upend what has been universally accepted in the scientific community—that we use only one side of our brains for speech,” says Bijan Pesaran, an associate professor in NYU’s Center for Neural Science and the study’s senior author. “In addition, now that we have a firmer understanding of how speech is generated, our work toward finding remedies for speech afflictions is much better informed.”

Many in the scientific community have posited that both speech and language are lateralized—that is, we use only one side of our brains for speech, which involves listening and speaking, and language, which involves constructing and understanding sentences. However, the conclusions pertaining to speech generally stem from studies that rely on indirect measurements of brain activity, raising questions about characterizing speech as lateralized.

To address this matter, the researchers directly examined the connection between speech and the neurological process.

Specifically, the study relied on data collected at NYU ECoG, a center where brain activity is recorded directly from patients implanted with specialized electrodes placed directly inside and on the surface of the brain while the patients are performing sensory and cognitive tasks. Here, the researchers examined brain functions of patients suffering from epilepsy by using methods that coincided with their medical treatment.

“Recordings directly from the human brain are a rare opportunity,” says Thomas Thesen, director of the NYU ECoG Center and co-author of the study.

“As such, they offer unparalleled spatial and temporal resolution over other imaging technologies to help us achieve a better understanding of complex and uniquely human brain functions, such as language,” adds Thesen, an assistant professor at NYU Langone.

In their examination, the researchers tested the parts of the brain that were used during speech. Here, the study’s subjects were asked to repeat two “non-words”—“kig” and “pob.” Using non-words as a prompt to gauge neurological activity, the researchers were able to isolate speech from language.

An analysis of brain activity as patients engaged in speech tasks showed that both sides of the brain were used—that is, speech is, in fact, bi-lateral.

“Now that we have greater insights into the connection between the brain and speech, we can begin to develop new ways to aid those trying to regain the ability to speak after a stroke or injuries resulting in brain damage,” observes Pesaran. “With this greater understanding of the speech process, we can retool rehabilitation methods in ways that isolate speech recovery and that don’t involve language.”

(Source: nyu.edu)