How to Grow a Bigger Brain

Mar 06, 2006
A newly hatched trout (Rebecca Kihslinger/UC Davis photo)
A newly hatched trout (Rebecca Kihslinger/UC Davis photo)

Hatchery-reared steelhead trout show increased growth of some parts of the brain when small stones are scattered on the bottom of their tank, according to a new study by researchers at UC Davis. The brains of those young fish were closer to those of salmon reared in the wild, and the fish also showed behavior closer to wild than to hatchery-reared fish.

"There's an obvious difference between the hatchery and the wild fish," said graduate student Rebecca Kihslinger, who carried out the study with Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis. "A simple change affected brain growth in a large-scale way."

The results could affect the design of hatcheries for breeding fish to restock wild populations, Kihslinger said. The study is published in the February 2006 issue of the Journal of Experimental Biology.

Wild steelhead lay their eggs in gravel nests on the riverbed. After hatching, the fry, called alevins, stay among the gravel and live off their yolk sac until they emerge as free-swimming fry. In hatcheries, the fish are reared in tanks of clean, well-aerated water, but without environmental features or enrichment.

Earlier work by Nevitt's lab at UC Davis and other labs has shown differences between hatchery-reared and wild fish, Kihslinger said. But most studies have looked at older fish, and have not distinguished between the effects of selective breeding for "domesticated" fish and of the environment in which the fish live.

Kihslinger reared steelhead in regular tanks and in tanks scattered with small stones. She videotaped the fish, and measured the size of their brains after 10 to 12 days, when the fish were emerging as free-swimming fry. She also studied fish reared in natural conditions in rivers.

Fish reared in both sets of tanks had brains of similar size, but the cerebellum, a part of the brain that controls movement and body position, was significantly larger in fish reared with stones. Those fish also moved around less, perhaps using their yolk reserves more efficiently.

Fish reared in the river had larger brains than either group of fish reared in tanks, but the relative size of the cerebellum compared to the rest of the brain was about the same as in fish reared in tanks with stones.

Source: UC Davis

Explore further: Greenland darkening to continue, predicts CCNY expert Marco Tedesco

Related Stories

Scientists eye YouTube cave videos to track water levels

36 minutes ago

A spot outside Riyadh for city residents who want to cool off is enabling scientists to do more than enjoy the beauty of their surroundings; they are using YouTube videos to track its rising water levels. ...

Mexico boosts protection of near-extinct porpoise

4 hours ago

Mexico is greatly expanding a protected area of the Gulf of California and boosting navy patrols in an effort to save the vaquita marina, a small porpoise facing imminent extinction.

Court monitor: Apple antitrust cooperation has 'declined'

4 hours ago

Apple Inc.'s cooperation with efforts to improve its compliance with antitrust laws after a federal judge concluded it colluded with electronic book publishers to raise prices five years ago took on an "adversarial tone" ...

SEC questions LA Unified on use of bonds for iPad project

4 hours ago

The Securities and Exchange Commission recently questioned Los Angeles Unified School District officials as part of informal inquiry into whether they properly used bond funds for a beleaguered $1.3 billion project to provide ...

Recommended for you

College rankings go under the microscope

9 hours ago

Parents, students and admissions officials have combed through college and university rankings for years. However, education researchers have largely ignored the controversial lists. That's about to change, according to a ...

A call to US educators: Learn from Canada

23 hours ago

As states and the federal government in the U.S. continue to clash on the best ways to improve American education, Canada's Province of Ontario manages successful education reform initiatives that are equal parts cooperation ...

Devices or divisive: Mobile technology in the classroom

Apr 17, 2015

Little is known about how new mobile technologies affect students' development of non-cognitive skills such as empathy, self-control, problem solving, and teamwork. Two Boston College researchers say it's ...

User comments : 0

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.