Carol A. Barnes facts for kids

Carol A. Barnes is an American neuroscientist. This means she is a scientist who studies the brain and the nervous system. She is a special professor of psychology at the University of Arizona. Since 2006, she has led a special program for learning and memory in aging. She also directs the Evelyn F. McKnight Brain Institute.

Dr. Barnes has written over 170 scientific papers. Her main research looks at how the brain changes as people get older. Understanding these changes can help us learn more about brain problems like Alzheimer's disease. She also created the Barnes maze, a special test used to study memory.

Her Journey in Education

Carleton University in Ottawa, Canada

Carol Barnes earned her first degree in psychology from the University of California, Riverside, in 1971. She then went to Carleton University in Canada. There, she received her Master's degree in psychology in 1972. In 1977, she completed her Ph.D. in psychology from the same university.

After her Ph.D., Dr. Barnes worked as a researcher. She studied the brain and how it works at several universities. These included Dalhousie University, the University of Oslo, and University College London.

What Does a Brain Scientist Do?

Dr. Barnes is a leading expert in how learning and memory change with age. She works at The Evelyn F. McKnight Brain Institute. She is also a professor and director at the University of Arizona. There, she leads the Division of Neural Systems, Memory and Aging.

She is part of the BIO5 Institute, which studies complex life science problems. At BIO5, she works with students to research Alzheimer's disease and other brain conditions related to aging. Dr. Barnes also teaches subjects like cancer biology, neuroscience, and psychology.

Exploring the Aging Brain

Dr. Barnes has been involved in neuroscience research for over 40 years. Her goal is to better understand how the brain ages. Her interest in normal brain aging started when she noticed her own grandfather's memory declining.

She uses animal models, like monkeys and rats, in her research. This helps her understand how memory is affected during normal aging. It also helps her learn about the brain's biological processes involved. The knowledge gained from animal studies can lead to new treatments. These treatments aim to help older people keep their thinking skills longer.

Dr. Barnes uses many techniques in her research. These include studying behavior, brain structure, electrical activity in the brain, and genes. Much of her work focuses on the hippocampus. This is a brain area important for memory. She observes how brain cells communicate and studies genetic information.

The Barnes Maze: A Memory Test

The Barnes maze, a tool for studying spatial memory

To study how animals learn and remember locations, Carol Barnes created a special maze. This maze helps scientists test if mice can remember where an escape box is on a platform. The Barnes maze is now a common tool for memory testing in labs.

She designed the maze in 1979. It was a new way to study memory without using rewards or punishments. This also helped reduce stress for the animals during the tests.

The original maze was a round platform about 122 cm (4 feet) wide. It was raised 91 cm (3 feet) off the floor. Around the edge were 18 holes. Under one hole was a dark escape box. The other holes led nowhere.

In her study, Dr. Barnes tested mice in three ways:

• First, the mouse just had to find the escape box.
• Second, the escape box was moved to a new hole. The old hole was covered.
• Third, the escape box moved again, but the old hole was not covered.

Dr. Barnes and her team found that male mice generally did better in all tests. Younger mice also performed better. Older mice had trouble with the second and third tests. This showed that spatial memory (remembering locations) can get worse with age.

Using special brain scans called MRI, Dr. Barnes found something interesting. In normally aging rodent brains, the hippocampus did not change size. Instead, the amount of gray matter in the outer part of the brain changed. This helped scientists understand what a normally aging brain looks like. They could then compare it to brains affected by diseases like Alzheimer's.

Looking even closer, they found three main types of cells in the hippocampus. Two types of cells, called CA1 and CA3 pyramidal cells, stayed active and the same size. However, the number of granule cells in another part of the hippocampus, the dentate gyrus, decreased with age. The function of these cells also declined. This led Dr. Barnes to believe these gyrus cells are a "weak link" in the memory circuit of the hippocampus.

Studying Brains: From Rats to Monkeys

Different brain regions work together to form memories.

Besides studying rodents, Dr. Barnes has also used nonhuman primates, like macaque monkeys, in her research. Her early work with macaques helped connect brain data from rodents with brain scan data from older humans.

In one study, Dr. Barnes and her team found that older monkeys had trouble recognizing objects. They also had fewer special brain cells called inhibitory interneurons in the CA3 area of the hippocampus. These interneurons help control the activity of other brain cells. With fewer interneurons, the CA3 cells became too active. This finding matches what is seen in brain scans of older humans. Both fewer interneurons and increased activity in the hippocampus are linked to poorer thinking skills.

In another study, Dr. Barnes's team found that all mammals use a similar number of brain cells in the hippocampus to remember a single experience. This means that whether it's a rodent, a monkey, or a human, the brain uses a stable amount of neurons to remember something. However, because the hippocampus size varies, the percentage of neurons used is different. Rodents use about 40%, monkeys use 4%, and humans, with the largest hippocampus, use about 2.5%.

Dr. Barnes has also studied how "executive functions" change with age. Executive functions are higher-level thinking skills. These include paying attention, making decisions, and controlling impulses. These skills are managed by the prefrontal cortex part of the brain.

She studied two executive functions in macaques:

• Attentional monitoring and updating: This is the ability to change your behavior when rules change. For example, if the correct choice in a task changes, this skill helps you adapt. Dr. Barnes found that older monkeys needed more tries to learn new rules. This suggests that this executive function weakens with age.
• Set shifting: This is the ability to switch your attention between different tasks without losing accuracy. Dr. Barnes found that older monkeys actually did better than younger monkeys on tasks that required set shifting. This suggests that this skill might stay strong or even improve with age.

The most important discovery from these studies is that these two executive functions are separate. They are affected differently by aging. This means that different parts of the prefrontal cortex might age in different ways.

Finally, Dr. Barnes has studied how spatial networks and memories change in aging macaques. She looked at brain activity when monkeys were in cages, sitting, walking on a treadmill, and walking freely. Younger monkeys had distinct brain networks for each activity. However, older monkeys showed less distinct activity. This means the same brain network was active for all conditions. This suggests that spatial processing networks become less precise with age. This could explain why older individuals sometimes have trouble with spatial memory or get confused about locations.

Helping Others in Science

Dr. Barnes is known for helping women and people from disadvantaged backgrounds succeed in neuroscience. In 2010, she received the Mika Salpeter Lifetime Achievement Award. This award recognizes scientists who have achieved a lot and also helped women advance in neuroscience.

She also actively participates in programs that support high school students and minority students in research. In 2013, she gave a speech called "The Evolving Face of Neuroscience: Role of Women and Globalization."

Awards and Recognition

Carol A. Barnes has received many awards and honors throughout her career. These include:

• Being a Foreign Member of the Royal Norwegian Society of Sciences and Letters (since 2004).
• Being a Regents Professor at the University of Arizona (since 2004).
• Being a Fellow of the American Association for the Advancement of Science (since 2009).
• Receiving the Mika Salpeter Lifetime Achievement Award (2010).
• Receiving the Ralph W Gerard Prize in Neuroscience (2013).
• Receiving the APA Award for Distinguished Scientific Contributions (2014).
• Being elected to the National Academy of Sciences (2018).