Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shedding new light on infant brain development

19.02.2013
New study reveals how control of brain blood flow develops with age

A new study by Columbia Engineering researchers finds that the infant brain does not control its blood flow in the same way as the adult brain. The paper, which the scientists say could change the way researchers study brain development in infants and children, is published in the February 18 Early Online edition of Proceedings of the National Academy of Sciences (PNAS).

"The control of blood flow in the brain is very important" says Elizabeth Hillman, associate professor of Biomedical Engineering and of Radiology, who led the research study in her Laboratory for Functional Optical Imaging at Columbia. "Not only are regionally specific increases in blood flow necessary for normal brain function, but these blood-flow increases form the basis of signals measured in fMRI, a critical imaging tool used widely in adults and children to assess brain function. Many prior fMRI studies have overlooked the possibility that the infant brain controls blood flow differently."

"Our results are fascinating" says Mariel Kozberg, a neurobiology MD-PhD candidate who works under Hillman and is the lead author of the PNAS paper. "We found that the immature brain does not generate localized blood-flow increases in response to stimuli. By tracking changes in blood-flow control with increasing age, we observed the brain gradually developing its ability to increase local blood flow and, by adulthood, generate a large blood-flow response."

The study results suggest that fMRI experiments in infants and children should be carefully designed to ensure that maturation of blood-flow control can be delineated from changes in neuronal development. "On the other hand," says Hillman, "our findings also suggest that vascular development may be an important new factor to consider in normal and abnormal brain development, so our findings could represent new markers of normal and abnormal brain development that could potentially be related to a range of neurological or even psychological conditions."

Functional magnetic resonance imaging, or fMRI, is one of several brain-imaging methods that measure changes in blood flow to detect the presence and location of neuronal activity. In adults, blood-flow increases occur in specific regions of the brain during a particular task like moving your hand or reacting to a stimulus. FMRI relies upon measuring decreases in deoxygenated hemoglobin resulting from this blood-flow increase to understand which parts of the brain are responsible for different actions and emotions. FMRI and other brain-imaging methods are currently being widely used to explore brain development, and to understand disorders in infants and children including autism and ADHD.

"Until now, we had been studying blood flow in the adult brain," Hillman notes, "but we became interested in several studies that reported odd, sometimes negative, blood-flow responses in newborn and premature infants and decided to carefully explore what was different about the immature brain compared to the adult. Initially, I saw these studies as a way to watch how the adult system assembled itself during development. Then we realized how important our findings were to those using brain imaging to study child development and developmental disorders."

The team used a unique multispectral optical intrinsic signal imaging system (MS-OISI) built in Hillman's lab to perform the research. MS-OISI is a high-speed, high-resolution imaging approach that takes advantage of the different absorption spectra of deoxygenated and oxygenated hemoglobin in order to determine changes in the concentrations of each. The researchers found that, with increasing age, there was a gradual development of a localized increase in blood flow, while a strong, delayed decrease in flow was consistently present. Only by adulthood was the positive increase able to balance the decrease in flow.

"Our results suggest that the infant brain might not be able to generate localized blood- flow increases, even if there is neuronal activity occurring, and that the development of blood- flow control occurs in parallel with early neuronal development," says Kozberg. "This could suggest that fMRI studies of infants and children may be detecting changes in both vascular and neuronal development—in fact, vascular development may be an important new factor to consider in normal and abnormal brain development."

The team also found that the younger age groups were highly sensitive to blood pressure increases in response to stimulation and that these increases can cause large increases in blood flow across the brain. "This finding indicates that the newborn brain is also unable to regulate its overall blood-flow levels," Kozberg explains. "This could explain earlier fMRI results in infants and children that were sometimes positive and sometimes negative, because it is difficult to tell whether blood pressure increases are occurring in infants and children. This result suggests that great care should be taken in setting stimulus thresholds in young subjects."

The researchers add that, since the newborn brain appears to be able to sustain itself without tightly controlled blood flow, their findings suggest that the infant brain may be intrinsically more resistant to damage due to a lack of oxygen than the adult brain. "This could be an important property to understand, both in terms of understanding how best to treat blood-flow problems in the newborn infant brain, which can cause lifelong problems such as cerebral palsy, and to potentially better understand how to treat the adult brain in conditions such as stroke," Hillman observes.

"Our lab operates at the intersection of neuroscience and engineering," continues Hillman." Not only do we develop the imaging systems that let us investigate the living brain in new ways, but like all engineers, we're fascinated with figuring out 'how things work,' and the brain is no exception."

Next steps for Hillman and her team include further defining the cellular mechanisms underlying the developing hemodynamic response at a cellular and microvascular level, using methods such as high-speed and multi-plane in-vivo two-photon microscopy, another technique developed in the lab. They're particularly interested in tracking changes in neuronal activity, microvascular architecture and connectivity, and the distribution and activity of other cellular populations thought to be associated with neurovascular coupling as a function of development.

"This will help us understand how the neonatal brain is different, and better understand how mature blood-flow control mechanisms in the adult brain work," says Kozberg.

Adds Hillman, "We are also keen to take this research into the clinic and explore whether our findings could improve diagnosis and monitoring of newborn infants. Our findings so far feel like just the tip of the iceberg. There is so much more for us to do now to understand why the infant brain is so different, and how we can use our findings to improve understanding of a wealth of devastating childhood and developmental conditions."

This research was supported by grants and student fellowships from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, the National Science Foundation, the National Defense Science and Engineering Graduate Fellowship, the Medical Scientist Training Program, and the Human Frontier Science Program. Hillman is also a member of the Columbia University graduate program in Neurobiology and Behavior and the Kavli Institute for Brain Sciences.

Holly Evarts | EurekAlert!
Further information:
http://www.columbia.edu

More articles from Health and Medicine:

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

nachricht Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>