Stress makes for a smaller short-term memory.

This notion was the take-home message of a neuroscience seminar yesterday, said Jeff Edwards, a physiology and developmental biology associate professor.

"Some acute stress is good," he said. "It's long-term stress that's bad on your memory."

Edwards discussed learning and memory mechanisms in the hippocampus. The hippocampus is a brain structure involved in declarative memories or what we experience in our lives.

Hippocampus means seahorse because the structure looks like a seahorse when taken from the brain.

Edwards discussed a case that helped researchers understand that the hippocampus is critical for memory formation.

In 1953, Henry Molaison was suffering from severe seizures. To alleviate the seizures, doctors removed his hippocampus. He lost his memory upon recovery. He had a working memory, which means he remembered things for a minute or less.

Molaison's MRI scans are available for anyone who wants to study them, Edwards said.

Because taking out the hippocampus results in memory loss, doctors no longer remove it.

In 1973, Bliss and Lomo began studying communication in the brain between two neurons, which is a synapse. They also examined long-term pontentiation or LTP, an increase in synapses.

Blocking LTP means you block memory formation. LTP is critical to short-term memory, he said.

Lauren Dean, a junior from Boyle, Miss., majoring in PDBio, said she is curious about the LTP function.

"More research will help us learn whether it wipes the slate clean to make stronger memories," she said.

Another topic of the seminar was about memory formation.

Memories are formed immediately upon our experience of something in our environment, Edwards said.

If short-term memory never forms, it's impossible to form long-term memory, he said.

The hippocampus contains two cells. When one cell is depressed, a person loses inhibition and becomes more excited.

Researchers cut up the brain to study it at an in-depth level.

Edwards said brains work on electrical currents and increasing motor activity increases energy storage, which helps people with neurodegenerative diseases such as Alzheimer's and Parkinson's.

Dean said she is fascinated that the research spoken about in the lecture is being used for understanding neurodegenerative diseases.

She plans to go to medical school and to practice psychiatry where she can better learn how neurodegenerative diseases work.

"It was interesting learning about memories on a cellular level," said Timise Brough, a junior from Provo majoring in PDBio. "The creation of more synapses creates a stronger long-term memory."

Copyright Brigham Young University 19 Feb 2009