Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Humans have more distinctive hearing than animals

01.04.2008
Do humans hear better than animals? It is known that various species of land and water-based living creatures are capable of hearing some lower and higher frequencies than humans are capable of detecting.

However, scientists from the Hebrew University of Jerusalem and elsewhere have now for the first time demonstrated how the reactions of single neurons give humans the capability of detecting fine differences in frequencies better than animals.

They did this by utilizing a technique for recording the activity of single neurons in the auditory cortex while subjects were exposed to sound stimuli. The auditory cortex has a central role in the perception of sounds by the brain.

Current knowledge on the auditory cortex was largely based on earlier studies that traced neural activity in animals while they were exposed to sounds. And while such studies have supplied invaluable information regarding sound processing in the auditory system, they could not shed light on the human auditory system’s own distinctive attributes.

... more about:
»auditory »frequencies »neural »neurons

Experimental study of neural activity in the human auditory cortex has been limited until now to non-invasive techniques that gave only a crude picture of how the brain responds to sounds. But recently, investigators from the Hebrew University, the University of California, Los Angeles (UCLA), the Tel Aviv Sourasky Medical Center and the Weizmann Institute of Science were successful in recording activity of single neurons in the auditory cortex while the subjects were presented with auditory stimuli. They did this by utilizing an opportunity provided during an innovative and complicated clinical procedure, which traces abnormal neural activity in order to improve the success of surgical treatment of intractable epilepsy,

The researchers included Prof. Israel Nelken of the Department of Neurobiology at the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jerusalem, Prof. Itzhak Fried from UCLA and Tel Aviv Medical Center, and Prof. Rafi Malach of the Weizmann Institute of Science, together with their students Roy Mukamel and Yael Bitterman. Their work was described in an article appearing in the journal Nature.

In tests measuring response to artificial sounds, the researchers found that neurons in the human auditory cortex responded to specific frequencies with unexpected precision. Frequency differences as small as a quarter of a tone (in western music, the smallest interval is half a tone) could be reliably detected from individual responses of single neurons.

Such resolution exceeds that typically found in the auditory cortex of other mammalian species (besides, perhaps, bats, which make unique use of their auditory system), serving as a possible correlate of the finding that the human auditory system can discriminate between frequencies better than animals. The result suggests that the neural representation of frequency in the human brain has unique features.

Interestingly, when the patients in the study were presented with “real-world” sounds – including dialogues, music (from "The Good, the Bad and the Ugly" soundtrack) and background noise – the neurons exhibited complex activity patterns which could not be explained based solely on the frequency selectivity of the same neurons. This phenomenon has been shown in animal studies but never before in humans.

Thus, it can be seen that in contrast to the artificial sounds, behaviorally relevant sounds such as speech and music engage additional, context-dependant processing mechanisms in the human auditory cortex.

Jerry Barach | Hebrew University
Further information:
http://www.huji.ac.il

Further reports about: auditory frequencies neural neurons

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>