For 30 years, pioneering neuroscientist Gina R. Poe, Ph.D., has researched the critical role sleep plays in learning, remembering memories, and then forgetting them.

As speaker for the Carole Mendelson, Ph.D., Distinguished Visiting Professorship Lecture, Dr. Poe addressed the many reasons why sleep is essential for humans and animals in her presentation “Mechanism of Sleep for Memory, Consolidation, and Circuit Remodeling.” The April 9 lecture was hosted by the Women in Science and Medicine Advisory Committee (WISMAC).

Event attendees applaud following the intriguing presentation by Dr. Poe on sleep and memory.

Even elephant seals snooze during 30-minute dives into the ocean, said Dr. Poe, Director of the UCLA Brain Research Institute. As they spiral and sink to the ocean floor, the animals enter rapid eye movement (REM) sleep, which is characterized by increased brain activity.

“They sink more and more and go into REM sleep while they are falling,” Dr. Poe said. “Their bodies are so inactive, and yet their brains are very active.”

Like brains in elephant seals, human brains are highly active during REM sleep. It is critical for brain development, especially during the first years of life, and helps the brain process emotional experiences before discarding them.

From left: WISMAC Chairs Kimberly Kho, M.D., M.P.H., Professor of Obstetrics and Gynecology, and Ondine Cleaver, Ph.D., Professor of Molecular Biology, talk with Dr. Poe following the event.

“Basically, REM sleep is for remembering until it is consolidated, and then it is for forgetting,” Dr. Poe said.

In her research, Dr. Poe has found that activity in the brain during REM sleep is consistent with the filing of new memories to long-term storage sites in the brain’s neocortex and the elimination of memories from the temporary storage place of the hippocampus once they have been successfully put away.

“This process of organization and cleaning allows our memories to be coherent as we continue to learn and readies our memory-making machinery for new learning the next day,” Dr. Poe said.

In her lab, Dr. Poe studies how the activity of neurons during learning reactivates in a unique pattern during sleep. Her team discovered how this activity updates the neural memory code. Both strengthening and weakening the connections between neurons in a network sculpts that network into shape as we form new memories, then integrates them into old schema, Dr. Poe said.

The conditions of sleep are perfect for that sculpting process, called memory consolidation, when all is well, Dr. Poe said. However, there are many places where this process can malfunction during sleep to distort or block this memory consolidation process. The neurotransmitters that should be present or absent during any given sleep state could present in the wrong ratio. The electrical activity patterns and their coordination between brain sites could also be missing or mistimed.

A participant in the Celebration of Women in Science Poster Session explains her research to an attendee.

For example, the hormone norepinephrine should be absent when people dream, but at certain times of the female cycle, it persists during REM sleep, disabling the elimination of memories from the temporary structures and perhaps underlying the reason that females are more susceptible to post-traumatic stress disorder and Alzheimer’s disease, Dr. Poe said.

“Sleep and dreaming are not a waste of time, but important and unique opportunities for the brain to reorganize itself in light of new information for our mental and neurological health,” Dr. Poe said.

As an influential researcher, Dr. Poe was the perfect choice for the Carole Mendelson Visiting Professorship, which has played a vital role in highlighting the accomplishments of exceptional female clinicians and scientists, said Ondine Cleaver, Ph.D., WISMAC co-Chair and Professor of Molecular Biology.

“We were excited to welcome Dr. Poe as this year’s WISMAC Carole Mendelson Visiting Professor because she embodies the spirit of curiosity-driven science and a deep commitment to mentorship,” Dr. Cleaver said.

Members of the Women in Science and Medicine Advisory Committee gather for a photo following the program.

Dr. Poe, who earned her Ph.D. in basic sleep in the Neuroscience Interdepartmental Program at UCLA and then went to the University of Arizona for her postdoctoral studies, has been encouraging young researchers throughout her career. At UCLA, she has mentored students, served in university faculty governance, and led five different programs designed to diversify the neuroscience workforce and increase representation of people of the global majority in the STEM fields.

“Through recounting her discoveries, unexpected findings, and personal growth, Dr. Poe relayed her inspiring scientific journey,” Dr. Cleaver said. “It shows us all what is possible.”

In addition to the lecture, WISMAC also presented the Celebration of Women in Science Poster Session, highlighting exceptional research being done across UT Southwestern to inspire the next generation of researchers.