Neuroscience

A new artificial intelligence–based technique for measuring fluid flow around the brain’s blood vessels could have big implications for developing treatments for neurological conditions.

A team led by Douglas Kelley, an associate professor of mechanical engineering, developed the novel measurements to calculate how cerebral blood vessels transport water-like fluids around the brain and help sweep away waste. Alterations in that flow are linked to Alzheimer’s, small vessel disease, strokes, traumatic brain injuries, and other conditions, but the changes are difficult to measure in living organisms.

The results are published in Proceedings of the National Academy of Sciences.

The work, done in collaboration with a researcher from Brown University, builds upon years of research led by Maiken Nedergaard, a professor in 乱伦强奸’s Departments of Neurology and Neurosurgery and codirector of the Center for Translational Neuromedicine.

The new technique “is a way to reveal pressures, forces, and the three-dimensional flow rate with much more accuracy than we can otherwise do,” says Kelley. “The pressure is important because nobody knows for sure quite what pumping mechanism drives all these flows around the brain yet. This is a new field.”

—Luke Auburn

Economic Equity

In the 1990s, the Supplemental Nutrition Assistance Program (SNAP)—the federal food assistance program whose roots date to the Depression-era Food Stamp Program—began including work requirements for most able-bodied recipients.

The stated rationale for work requirements enacted as part of the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 was that they would help recipients make a transition into the paid labor force.

But research by a team including Elena Prager, an assistant professor of economics at the Simon Business School, finds that work requirements are not effective in achieving that aim.

The group collected data from 2007 to 2015 to measure the effects of the period from 2009, when work requirements were suspended in response to the Great Recession, to 2013, when they were reinstated. In the study, published in American Economic Journal: Economic Policy, the researchers report that work requirements have led to notable reductions in SNAP participation among adults subjected to them but have had “no effects on employment.”

According to Prager and her coauthors, the declines in participation “are largest among beneficiaries who, prior to the reinstatement of work requirements, are homeless or have no earned income.”

Work requirements were modified this spring as part of negotiations over the federal debt ceiling. The final version of the Fiscal Responsibility Act of 2023, signed into law on June 3, included an exemption for homeless SNAP recipients.

—Karen McCally ’02 (PhD)

Cancer Diagnosis

Mammography is the gold standard for breast cancer diagnosis, but it’s not reliable in all cases, especially in people with dense breasts. According to the National Cancer Institute, that includes nearly half of all women aged 40 and older who get mammograms.

A team from the Medical Center and the Hajim School combined ultrasound with machine learning to examine previously detected masses in 121 study participants, about three quarters of whom had either dense or extremely dense breasts. The result: nearly 98 percent accuracy in predicting breast cancer in the masses. According to Kevin Parker, a professor of electrical and computer engineering and one of the researchers, that’s compared to an accuracy rate that can be as low as 50 percent using mammography on dense breast tissue.

The team of Parker, lead author Jihye Baek, a PhD student in Parker’s lab, and Avice O’Connell ’77M (Res), a professor of imaging sciences at the Medical Center, published the findings in the journal Machine Learning: Science and Technology.

The researchers note that ultrasound is less expensive than mammography, portable, and radiation-free, making it a desirable tool, especially in developing countries. But at present, ultrasound is used only as a complement to standard mammography. That’s because ultrasound finds many masses within a breast, most of which are not cancer.

It will take some time before the team’s method can be widely adopted. “In the next stage of our research, we’ll be working with much larger sets of data,” says Parker.

—Peter Iglinski ’17 (MA)

Geoscience of Plate Tectonics

Scientists have long assumed that plate tectonics—the process in which large, jigsaw puzzle–like plates that compose Earth’s crust and upper mantle shift, allowing heat from the planet’s interior to escape to the surface—is necessary for the emergence of life. But new research led by John Tarduno, the William R. Kenan, Jr. Professor in the Department of Earth and Environmental Sciences, casts doubt on that assumption.

In a study published in Nature, Tarduno reports the finding that mobile plate tectonics was not occurring during the time when the first life forms emerged on Earth. Instead, Earth was releasing heat through what is known as a stagnant lid regime, in which large plumes of molten material originating in Earth’s deep interior cause the outer layer to crack.

“We think plate tectonics, in the long run, is important for removing heat, generating the magnetic field, and keeping things habitable on our planet,” says Tarduno. “However, our data suggests that when we’re looking for exoplanets that harbor life, the planets do not necessarily need to have plate tectonics.”

—Lindsey Valich

Pediatric Psychiatry

Researchers at the Del Monte Institute for Neuroscience are coming closer to finding a possible target for treating neuropsychiatric diseases that emerge in early adulthood, when the brain’s dopamine system is malleable and not fully mature. Those diseases include schizophrenia and substance abuse disorders.

A team led by Kuan Hong Wang, a professor in the Departments of Neuroscience and of Pharmacology and Physiology, and Rianne Stowell, a postdoctoral fellow in Wang’s lab, targeted underperforming neurons in the dopamine system that connect to the frontal cortex, circuitry that’s essential to higher cognitive processing and decision making.

They found that stimulating the cells that provide dopamine to the frontal cortex strengthened the circuit and counteracted structural deficiencies in the brain that cause long-term symptoms.

The findings, published in the journal eLife, suggest that increasing the activity of the dopamine system in adolescents may provide a path toward long-lasting changes that persist into adulthood, says Stowell.

“If we can target the right windows in development and understand the signals at play, we can develop treatments that change the course of these brain disorders.”

—Kelsie Smith Hayduk