Stories about: neuroimaging

‘See through,’ high-resolution EEG recording array gives a better glimpse of the brain

Transparent microelectrodes allow EEG recording at the single-neuron level, with simultaneous 2-photon optical imaging of calcium activity.
Transparent microelectrodes allow EEG recording at the single-neuron level, with simultaneous 2-photon optical imaging of calcium activity. (CREDIT: Yi Qiang et al. Sci. Adv. 4, eaat0626 (2018).)

Electroencephalography (EEG), which records electrical discharges in the brain, is a well-established technique for measuring brain activity. But current EEG electrode arrays, even placed directly on the brain, cannot distinguish the activity of different types of brain cells, instead averaging signals from a general area. Nor is it possible to easily compare EEG data with brain imaging data.

A collaboration between neuroscientist Michela Fagiolini, PhD at Boston Children’s Hospital and engineer Hui Fang, PhD at Northeastern University has led to a highly miniaturized, see-through EEG device. It promises to be much more useful for understanding the brain’s workings.

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Science Seen: Imaging early auditory brain development

Auditory brain development - Heschl’s gyrus at 28 and 40 weeks
Copyright © 2018 Monson et al.

Babies can hear and respond to sounds, including language, before birth. In fact, research shows that babies learn to recognize words in the womb. Now, an advanced MRI technique called diffusion tensor imaging is providing a fine-tuned view of when different brain areas mature, including the areas that process sound. And the findings suggest that babies born prematurely may have disruptions in auditory brain development and in speech.

Investigators at Boston Children’s Hospital, Brigham and Women’s Hospital, Washington University School of Medicine in St. Louis and University College London analyzed advanced MRI brain images from 90 preterm infants and 15 infants born at full term (40 weeks). Fifty-six of the preterm infants were imaged at multiple time points. As shown above, the team focused on a particular fold in the brain called Heschl’s gyrus (HG). This area contains the primary auditory cortex, the first part of the auditory cortex to receive sound signals, and the non-primary auditory cortex, which plays a higher-level role in processing those stimuli.

As seen in these sample images, the primary cortex has largely matured at 28 weeks’ postmenstrual age (PMA), whereas the non-primary auditory cortex has had a surge in development between 28 and 40 weeks’ PMA. Both regions appeared underdeveloped in the premature infants as compared with the infants born at term.

The study further found that disturbed maturation of the non-primary cortex was associated with poorer expressive language ability at age 2. The team suggests that this area may be especially vulnerable to disruption in a premature birth because it is undergoing such rapid change.

The study was published in eNeuro, an open-access journal from the Society for Neuroscience. Jeffrey Neil, MD, PhD, of Boston Children’s Department of Neurology, was senior author on the paper. First author Brian Monson, PhD, is now at the University of Illinois at Urbana-Champaign. Read more in the university’s press release.

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Science seen: Mapping touch perception in cerebral palsy

sensory brain mapping in cerebral palsy

Cerebral palsy (CP) is the most common motor disability of childhood. The brain injury causing CP disrupts touch perception, a key component of motor function. In this brain image from a child with CP (click to enlarge), the blue lines show nerve fibers going to the sensory cortex. The colored cubes at the top represent the parts of the sensory cortex receiving touch signals from the thumb (red cube), middle finger (blue) and little finger (green). An injury in the right side of the brain (dark area) has reduced the number of nerve fibers on that side, reducing touch sensation in the left hand and resulting in weakness.

Christos Papadelis, PhD, of Boston Children’s Hospital’s Division of Newborn Medicine hopes to use such sensory mapping information to develop better rehabilitation therapies. P. Ellen Grant, MD, director of the Fetal-Neonatal Neuroimaging and Developmental Science Center, Brian Snyder, MD, of the Cerebral Palsy Program and research assistant Madelyn Rubenstein are part of the team.

 

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Delivering a baby MEG

baby MEG
This array of sensors surrounding a baby’s head will give researchers and eventually clinicians a high-resolution image of neural activity.

Imagine you’re a clinician or researcher and you want to find the source of a newborn’s seizures. Imagine being able to record, in real time, the neural activity in his brain and to overlay that information directly onto an MRI scan of his brain. When an abnormal electrical discharge triggered a seizure, you’d be able to see exactly where in the brain it originated.

For years, that kind of thinking has been the domain of dreams. Little is known about infant brains, largely because sophisticated neuroimaging technology simply hasn’t been designed with infants in mind. Boston Children’s Hospital’s Ellen Grant, MD, and Yoshio Okada, PhD, are debuting a new magnetoencephalography (MEG) system designed to turn those dreams into reality.

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Early brain checkups for dyslexia, autism and more

Researchers are seeking to track the brain at earlier and earlier ages (here, the brain of a newborn baby born 10 weeks prematurely). © FNNDSC 2011

For the third year running, my daughter is participating in a dyslexia study she entered at age 5, just after finishing preschool. Thinking she was part of a game, she spent about 45 minutes lying still in a rocket ship (in reality, an MRI scanner), doing mental tasks she believed would help lost aliens find their way back to their planet.

All the while, her brain was being imaged, helping a team led by Nadine Gaab of Children’s Laboratories of Cognitive Neuroscience to find a pattern indicating that she might be at risk for dyslexia. Such signatures might flag children who could benefit from early intervention, sparing them the frustration of struggling with dyslexia once in school.

Getting brain MRIs from young childrenwithout resorting to sedation — is a difficult feat (Gaab and colleagues shared their protocol in the Journal of Visualized Experiments). But as reported in today’s Boston Globe, Gaab and Children’s neuroradiologist Ellen Grant are pushing the envelope even further, trying to find MRI signatures of dyslexia in infants.

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Glimpsing a baby’s brain: Advanced neuroimaging

Surprisingly little is known about the brains of babies under age 2 — because of the challenges of safely imaging children so young. Head-circumference measures at the pediatrician’s office tell very little about what’s going on inside. But there’s much to know, because rapidly developing brains are vulnerable to injury.

Here, Ellen Grant, a neuroradiologist trained in theoretical physics, describes how advanced imaging techniques and computational science are providing a better understanding of the newborn and even fetal brain. With these tools, neurologists can watch the brain as it forms and folds, track the growth of individual brain structures, and detect problems in brain organization before anything can be noticed by parents or physicians — then correlate these measurements with child developmental measures.

Children’s Hospital Boston is building a neuroimaging facility with specially designed, baby-sized equipment — the only one in the world to be situated near a neonatal and pediatric intensive care unit. It will help answer questions like: What prenatal brain development is missed when a baby is born even two weeks shy of its due date? What does a brain structure growing out of synch at 6 months mean for language development in preschool? Are interventions for brain injury, such as hypothermia, effective? Grant’s ultimate goal is to get advanced neuroimaging into routine clinical care, to monitor infants and newborns with brain injury, predict their future course, and evaluate new treatments.

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