Category: Research

How electric fish got their big brains (Links to an external site)

Researchers have mapped the regions of the brain in mormyrid fish in extremely high detail. The new measurements can help illuminate longstanding questions in neuroanatomy. As brains get bigger, do all regions of the brain scale up in a predictable way? Or does natural selection act independently on separate regions of the brain — such that certain parts of the brain become enlarged in animals that have extra reasons to use them?

New maps hint at how electric fish got their big brains (Links to an external site)

Researchers from Washington University in St. Louis have mapped the regions of the brain in mormyrid fish in extremely high detail. In a new study published in the Nov. 15 issue of Current Biology, they report that the part of the brain called the cerebellum is bigger in members of this fish family compared to related fish—and this may be associated with their use of weak electric discharges to locate prey and to communicate with one another.

Carlson Lab receives NSF grant

Bruce Carlson, associate professor of biology in Arts & Sciences, received $700,000 from the National Science Foundation for research on “Adaptive rewiring of a sensory network through spike-timing-dependent plasticity.”

Big Brains Are Rare: Here’s Why (Links to an external site)

The evolutionary ties around large brains have been subjected to scientific debate. However, recent study suggests that there are some associated evolutionary flaws to the mechanisms of physiologically supporting large brains. The research underlines that the high levels of energy expenditure could be responsible for the rarity of big brained creatures. Much of the research on the consequences of having a bigger brain revolves around the cognitive capacities of people, who are believed to be highly superior to any other living beings. However, research published, Dec. 21, in the journal Proceedings of the Royal Society B suggests this comes at a cost.

Why big brains are rare: Studies of electric fish show really big brains evolve only if energy intake goes up (Links to an external site)

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As a species, we’re so brain-proud it doesn’t occur to most of us to ask whether a big brain has disadvantages as well as cognitive benefits.

“We can think of tons of benefits to a larger brain, but the other side of that is brain tissue is incredibly ‘expensive’ and increasing brain size comes at a heavy cost,” said Kimberley V. Sukhum, a graduate student in biology in Arts & Sciences at Washington University in St. Louis.

Why big brains are rare (Links to an external site)

Do big-brained creatures steal energy for their brains from other organs or eat more to supply this expensive tissue? New work in large-brained fish suggests skimping elsewhere is not enough to meet the energy demands of an extreme brain.

Why Big Brains Are Rare (Links to an external site)

Studies of electric fish support the idea that really big brains can evolve only if constraints on energy intake are lifted.

As a species we’re so brain-proud it doesn’t occur to most of us to ask whether a big brain has disadvantages as well as cognitive benefits.

“We can think of tons of benefits to a larger brain, but the other side of that is brain tissue is incredibly ‘expensive’ and increasing brain size comes at a heavy cost,” said Kimberley V. Sukhum, a graduate student in biology in Arts & Sciences at Washington University in St. Louis.

Fish talk to each other electrically

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There are differences between species. The most sensitive can determine the signaler’s species, sex, age, relative dominance status, and possibly even individual identity. They can also detect emotional states, such as aggression, submission, courtship and active exploration. This was reported in Science in 2011, according to biologist Dr Bruce Carlson of Washington University in St. Louis, who […]

These fish talk to each other with electric tails (Links to an external site)

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“If you’re solitary and territorial and you detect another fish in the area, you want to know exactly who that fish is. Is it a potential competitor, a potential mate, or a different species you’re not worried about,” says Bruce Carlson. “On the other hand, if you’re living in a shoal or school of fish, it’s not so important to identify individuals. Just sticking with the group is going to be a successful strategy.”

Fish that have their own fish finders (Links to an external site)

In a 2011 article in Science that described a group of mormyrids able to perceive subtle variations in the waveform of electric signals, Washington University in St. Louis biologist Bruce Carlson, PhD, noted that another group of mormyrids are much less discriminating.

Fish That Have Their Own Fish Finders (Links to an external site)

In the August 4 issues of the online journal eLIFE, Carlson and graduate student Christa Baker describe how they discovered the basis for the perceptual differences between the two groups of fish by studying the fish’s sensory receptors.