Stories about: neuroscience

Fruit flies’ love lives could clarify brain cells’ role in motivation

If you have children present, you might want to click out of this post. But if you want to understand motivation, you’ll want to know about the sexual behavior of fruit flies.

In the brain, motivational states are nature’s way of matching our behaviors to our needs and priorities. But motivation can go awry, and dysfunction of the brain’s motivation machinery may well underlie addiction and mood disorders, says Michael Crickmore, PhD, a researcher in the F.M. Kirby Neurobiology Center. “Basically, every behavior or mood disorder is a disorder of motivation,” he says.

It’s already known that brain cells that communicate via the chemical dopamine are important in motivation—and are also implicated in ADHD, depression, schizophrenia and addiction. But what exactly are these cells up to, and who are they talking to? That’s where fruit flies come in.

“We study motivation in a simple system that we can bash very hard,” says Crickmore.

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Melanopsin, lighting and you

color spectrum melanopsin
A deep-dive view of non-image vision may refine our understanding of light and health.

Back in the day, the 1980s to be specific, there was a brief fad around amber-on-black computer screens (as opposed to green-on-black or white-on-black) for supposed ergonomic reasons. My computer had one, along with its 5 ¼” floppy drives (remember those?).

More recently, with kids texting at night and people logging late hours on computers and devices, there’s been a recognition that artificial light at night is bad for sleep and disruptive to physiology overall, with blue light increasingly recognized as the culprit.

That’s given birth to some new fads. You can now download programs to eliminate blue light from your computer screen at night or buy amber-tinted glasses for computing and gaming to “filter the harsh spectra” of light. Airlines are using “mood” lighting to mimic sunrises and sunsets, which supposedly reduces jetlag.

In a paper in Neuron last week, Alan Emanuel and Michael Do, PhD, of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital and Harvard Medical School provide some science to support and inform these fads, as well as the use of light therapy for conditions like seasonal affective disorder.

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Mapping mosaicism: Tracing subtle mutations in our brains

brain genetic mosaicism
(Erik Jacobsen, Threestory Studio. Used with permission.)

DNA sequences were once thought to be the same in every cell, but the story is now known to be more complicated than that. The brain is a case in point: Mutations can arise at different times in brain development and affect only a percentage of neurons, forming a mosaic pattern.

Now, thanks to new technology described last week in Neuron, these subtle “somatic” brain mutations can be mapped spatially across the brain and even have their ancestry traced.

Like my family, who lived in Eastern Europe, migrated to lower Manhattan and branched off to Boston, California and elsewhere, brain mutations can be followed from the original mutant cells as they divide and migrate to their various brain destinations, carrying their altered DNA with them.

“Some mutations may occur on one side of the brain and not the other,” says Christopher Walsh, MD, PhD, chief of Genetics and Genomics at Boston Children’s Hospital and co-senior author on the paper. “Some may be ‘clumped,’ affecting just one gyrus [fold] of the brain, disrupting just a little part of the cortex at a time.”

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Sensory processing problems in autism: Mice reveal brain mechanisms, treatment potential

sensory processing autism
(Image courtesy Nadine Gogolla)

Families of children with autism spectrum disorder have long noted sensory processing difficulties such as heightened sensitivity to noise, touch or smell—or even specific foods or clothing textures—earning sensory processing a place in the official DSM-5 description of the disorder.

“A high proportion of kids with autism spectrum disorder will have difficulty tolerating certain kinds of sensory inputs,” says Carolyn Bridgemohan, MD, co-director of the Autism Spectrum Center at Boston Children’s Hospital. Others, she adds, are less sensitive to certain stimuli, showing a higher tolerance for pain or excessively hot or cold temperatures.

A study published last week in Neuron uses mouse models to shed new light on the brain mechanisms that underlie sensory processing abnormalities in autism.

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Can old peripheral nerves learn new tricks? Only the Schwann cells know for sure

peripheral nerve injury

About six weeks ago, a glass shattered in my hand, severing the nerve in my pinky finger. The feeling in my fingertip still hasn’t returned, and now I know why: I’m too old.

Going back to World War II, it’s been speculated that recovery of peripheral nerve injuries—like those in limbs and extremities—is influenced by age. And studies indicate that peripheral neuropathy is common in people over 65, including those who have received cancer chemotherapy, and often unexplained.

“When you’re very young, the system is very plastic and able to regenerate,” Michio Painter told me recently. He is a graduate student in the laboratory of Clifford Woolf, PhD, director of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital. “After that, there’s a gradual decline. By the age of 30, much of this plasticity is gone.”

Traditionally, this decline has been thought to reflect age-related differences in neurons’ ability to regrow, but when Painter studied neurons in a dish, he couldn’t confirm this.

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Does musical training help kids do better in school?

music and executive functionMy daughter just surprised me by signing up for fifth grade band starting this fall. To my further delight, some new research—using both cognitive testing and brain imaging—suggests that as she practices her clarinet, she also may be honing her executive functions.

Like a CEO who’s on top of her game, executive functions—separate from IQ—are those high-level brain functions that enable us to quickly process and retain information, curb impulsive behaviors, plan, make good choices, solve problems and adjust to changing cognitive demands. While it’s already clear that musical training relates to cognitive abilities, few previous studies have looked at its effects on executive functions specifically.

The study, appearing this week in PLOS ONE, compared children with and without regular musical training, as well as adults. To the researchers’ knowledge, it’s the first such study to use functional MRI (fMRI) of brain areas associated with executive function and to adjust for socioeconomic factors.

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Your brain on soccer: Thinking with your feet

Classic Penfield motor homunculus could be different in soccer playersOne of my very favorite images in science, Dr. Wilder Penfield’s classic motor homunculus, shows how much brain real estate is devoted to controlling movement of different parts of the body. Notice the huge hands and the tiny feet. As the World Cup gets underway, soccer fan Jeffrey Holt, PhD, also a Boston Children’s Hospital neuroscientist, writes that soccer is more than just a great sport, it’s “a triumphant display of the incredible plasticity of the human brain… because the soccer player is limited by one simple rule: no hands!”

Though no one’s actually taken a look, Holt imagines that the brains of great soccer players like Cristiano Ronaldo, Lionel Messi or Neymar would have much expanded neural representation of the feet. Read more in his post on WBUR-Boston’s Cognoscenti blog.

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Neuronal migration and a well-configured cortex: A neuroscientist looks back

Normal brain and Double Cortex-Courtesy Christopher Walsh(Above: In double cortex syndrome, causing epilepsy and mental retardation, an extra cortex forms just beneath the cerebral cortex [right]. The causative DCX mutation interferes with migration of neurons during the cortex’s early development. Courtesy Walsh Lab)

The journal Neuron, celebrating its 25th anniversary, recently picked one influential neuroscience paper from each year of the publication. In this two-part series, we feature the two Boston Children’s Hospital’s scientists who made the cut. The Q&A below is adapted with kind permission from Cell Press. (See part 1)

Key to well-tuned brain function is the migration of neurons to precise locations as the brain develops. The long journey begins deep inside the brain and ends in the outer cerebral cortex—where our highest cognitive functions lie. Christopher Walsh, MD, PhD, has shown that several genetic mutations causing neurodevelopmental disorders disrupt this neuronal migration, landing neurons in the wrong places. Each gene governs a specific sub-task: one kicks off the migration process; others stop migration when neurons have arrived in the right location.

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Microglia’s role in brain development: A neuroscientist looks back

The journal Neuron, celebrating its 25th anniversary, recently picked one influential neuroscience paper from each year of the publication. In this two-part series, we feature the two Boston Children’s Hospital’s scientists who made the cut. The Q&A below is adapted with kind permission from Cell Press.

Microglial cell with synapses
CAUGHT IN THE ACT: This microglial cell is from the lateral geniculate nucleus, which receives visual input from the eyes. The red and blue are synapses that it has engulfed. (Blue synapses represent inputs from the same-side eye; red, the opposite-side eye.)

In 2012, Beth Stevens, PhD, and colleagues provided a new understanding of how glial cells shape healthy brain development. Glia were once thought to be merely nerve “glue” (the meaning of “glia” from the Greek), serving only to protect and support neurons. “In the field of neuroscience, glia have often been ignored,” Stevens told Vector last year.

No longer. Stevens’s 2012 paper documented that microglia—glial cells best known for their immune function—are no passive bystanders. They get rid of excess connections, or synapses, in the developing brain the same way they’d dispatch an invading pathogen—by eating them.

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What’s your lot in life? How you see it may affect your child’s brain

A fieldworker in Canta, Peru administers tablet-based games to a 12-year-old girl, taking a measure of her brain function.
A fieldworker in Peru administers cognitive tests to a 12-year-old girl. While socioeconomic circumstances can vary dramatically, how families perceive and adapt to them may be more critical in brain development.

Studies going back to the 1950s have linked objective socioeconomic factors—like parental income or education—to child health and achievement. Recent studies have extended this research, indicating that parental socioeconomic status (SES) also affects physiologic brain function in children. A new study, while small, is the first to suggest another potent factor: the mother’s self-perceived social status.

Margaret Sheridan, PhD, at Boston Children’s Hospital’s Labs of Cognitive Neuroscience, and colleagues studied 38 children, ages 8 to 12 years. Each child gave a saliva sample to measure levels of the stress hormone cortisol, and 19 also underwent functional MRI of the brain focusing on the hippocampus, a structure responsible for long-term memory formation (required for learning) and for reducing stress responses.

Their mothers, meanwhile, were shown a picture of a ladder and were asked to rank their social status on a scale of 1 to 10 as compared with others in the United States.

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