Researchers trace early journey of modulating cells in brain

July 28, 2011

Key cells in the brain region known as the hippocampus are formed in the base of the brain late in fetal life and undertake a long journey before reaching their final destination in the center of the brain shortly after birth, according to researchers at the National Institutes of Health.

The is involved with attention, navigation and converting short-term memories to long-term memories. Interneurons, the brain the researchers studied, regulate communication between networks of brain . Previous research suggests that brain cell networks in the hippocampus may be disrupted in developmental disorders, including , as well as in , ’s disease and schizophrenia.

“The hippocampus seems to be at the crossroads of many disorders affecting the brain,” said Chris McBain, Ph.D., chief of the Laboratory of Cellular and Synaptic Neurophysiology at the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). “With these findings, we can begin to understand how proper communication is established in the brain and to investigate why sometimes it breaks down in this critical area.”

Their findings appear in The Journal of Neuroscience.

In their experiments, the researchers worked with two kinds of genetically altered mice. The researchers examined the brains of fetal mice and pups at various stages of development, from about two weeks after conception until the baby mice were 1 month old. Cells generated in the brains of the mice at each stage emitted light from a fluorescent protein they contained.

Comparing the number and location of fluorescent cells at the various stages, the researchers were able to create a composite image of the early development and migration of interneurons. The researchers also examined individual interneurons in the animals’ brains and catalogued nearly two dozen different types.

The researchers demonstrated that the brain produces large quantities of interneurons just before the mouse is born. Typically, brain cells reside in areas of the brain very close to where they are generated, Dr. McBain explained. But interneurons, the researchers discovered, take two to three days to travel across the brain to the hippocampus.

Along the route, most of the new die. Cell counts began to drop after the mice were born, the researchers found. When the mice were five days old, about half of the cells had disappeared. By the time the mice were one month old, the researchers estimated that 80 percent of the new interneurons had died.

The remaining cells were integrated into the hippocampus and demonstrated typical activity, the showed. In the normally functioning brain, Dr. McBain explained, interneurons are incorporated in circuits connecting structures in different areas. In the circuit, they brake or sometimes stop signals at decisive moments. Working in concert with other cells in the circuit, they coordinate waves of activity across the brain.

“This work shows how the early development of the hippocampus is distinct from the rest of the brain,” said Dr. McBain. “It may also help us decide where to look when signals passing through somehow miss their mark.”

Explore further: Scientists discover new mechanism that may be important for learning and memory

Related Stories

Recommended for you

Artificial beta cells

December 8, 2016

Researchers led by ETH Professor Martin Fussenegger at the Department of Biosystems Science and Engineering (D-BSSE) in Basel have produced artificial beta cells using a straightforward engineering approach.

Key regulator of bone development identified

December 8, 2016

Loss of a key protein leads to defects in skeletal development including reduced bone density and a shortening of the fingers and toes—a condition known as brachydactyly. The discovery was made by researchers at Penn State ...

Researchers question lifelong immunity to toxoplasmosis

December 8, 2016

Medical students are taught that once infected with Toxoplasma gondii—the "cat parasite"—then you're protected from reinfection for the rest of your life. This dogma should be questioned, argue researchers in an Opinion ...

TET proteins drive early neurogenesis

December 7, 2016

The fate of stem cells is determined by series of choices that sequentially narrow their available options until stem cells' offspring have found their station and purpose in the body. Their decisions are guided in part by ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.