Brain Picks out Salient Sounds from Background Noise by Tracking Frequency and Time, Study Finds

July 23, 2013 — New research reveals how our brains are able to pick out important sounds from the noisy world around us. The findings, published online today in the journal eLife, could lead to new diagnostic tests for hearing disorders.

Our ears can effortlessly pick out the sounds we need to hear from a noisy environment -- hearing our mobile phone ringtone in the middle of the Notting Hill Carnival, for example -- but how our brains process this information (the so-called 'cocktail party problem') has been a longstanding research question in hearing science.

Researchers have previously investigated this using simple sounds such as two tones of different pitches, but now researchers at UCL and Newcastle University have used complicated sounds that are more representative of those we hear in real life. The team used 'machine-like beeps' that overlap in both frequency and time to recreate a busy sound environment and obtain new insights into how the brain solves this problem.

In the study, groups of volunteers were asked to identify target sounds from within this noisy background in a series of experiments.

Continued

Humans Evolved Flexible, Lopsided Brains

Tanya Lewis, LiveScience Staff Writer 

Date: 23 April 2013 Time: 07:01 PM ET 

The two halves of the human brain are not symmetrical. This lopsidedness, which arises during brain development, may be a stamp of the adaptability of the human brain, a new study suggests. 

Researchers compared geometric differences between brain scans of humans and chimpanzees. They observed structural asymmetries in both human and chimpanzee brains, but human brains were especially asymmetric. The findings, published online today (April 23) in the journal Proceedings of the Royal Society B, suggest human and chimp brains evolved a high degree of flexibility during development. 

The human brain is known to be asymmetric — the "left brain" is involved in language processing, for example, while the "right brain" is where spatial reasoning takes place. "It's very common that there are some areas that are bigger in the left hemisphere than in the right hemisphere," said lead study author Aida Gómez-Robles, an anthropologist at The George Washington University in Washington, D.C. 

Continued: http://www.livescience.com/28986-humans-evolved-asymmetric-brains.html

Human Brains Outpace Chimp Brains in Womb

ScienceDaily (Sep. 24, 2012) — Humans' superior brain size in comparison to their chimpanzee cousins traces all the way back to the womb. That's according to a study reported in the September 25 issue of Current Biology, a Cell Press publication, that is the first to track and compare brain growth in chimpanzee and human fetuses.

"Nobody knew how early these differences between human and chimp brains emerged," said Satoshi Hirata of Kyoto University.

Hirata and colleagues Tomoko Sakai and Hideko Takeshita now find that human and chimp brains begin to show remarkable differences very early in life. In both primate species, the brain grows increasingly fast in the womb initially. After 22 weeks of gestation, brain growth in chimpanzees starts to level off, while that of humans continues to accelerate for another two months or more. (Human gestation time is only slightly longer than that of chimpanzees, 38 weeks versus 33 or 34 weeks.)

Read on: http://www.sciencedaily.com/releases/2012/09/120924142922.htm