Navigation Links
Grasshopper love songs give insight into sensory tuning

As anyone whose nerves have been jangled by a baby's howl or who have been riveted by the sight of an attractive person knows, nature has evolved sensory systems to be exquisitely tuned to relevant input. A major question in neurobiology is how neurons tune the strength of their interconnections to optimally respond to such inputs.

Neuronal circuitry consists of a web of neurons, each triggering others by launching bursts of neurotransmitters at targets on receiving neurons to produce nerve impulses in those targets. Neurons adjust the strength of those connections adaptively, to amplify or suppress connections. Some four decades ago, a general principle called the "efficient coding hypothesis" was formulated, holding that sensory systems adjust to efficiently represent the complex, dynamic sounds, sights, and other sensory input from the environment.

Writing in the August 4, 2005, issue of Neuron, researchers led by Christian K. Machens of Cold Spring Harbor Laboratory and Andreas Herz of Humboldt-University Berlin describe experiments with grasshopper auditory neurons that reveal new details of such sensory coding. Their findings show that "optimal stimulus ensembles" that trigger the neurons differ from those the grasshopper hears in the natural environment but largely overlap with components of natural sounds found in mating and mate-location calls.

In their experiments, the researchers first played various snippets of white noise to isolated grasshopper auditory nerves and measured the electrophysiological signals reflecting the reactions of the auditory neurons to those sounds. These experiments revealed the distribution of stimuli called the "optimal stimulus ensemble" (OSE) that allowed the neurons in the system to perform optimally.

Once the researchers had characterized the OSE, they then analyzed how this measure compared to the neuronal response to natural sounds--including environmental sounds like the rustling of grass an d insect communication signals such as grasshopper or cricket mating calls.

They found that the OSEs of the receptors particularly matched characteristic features of species-specific acoustic communication signals used by grasshoppers to attract mating partners.

"Hence, instead of maximizing the average information gained about natural stimuli, the receptors appear to maximize the information gained about specific, but less often occurring aspects of the stimuli," concluded the researchers. "This result suggests that an organism may seek to distribute its sensory resources according to the behavioral relevance of the natural important stimuli, rather than according to purely statistical principles.

"For instance, if a few important stimuli within the natural environment need to be encoded with high precision, a large part of a system's coding capacity could be designated to encode these stimuli. Consequently, it may well be that even small subensembles strongly influence the coding strategy of sensory neurons. In this case, the optimal stimulus ensemble will not match the ensemble of all natural stimuli encountered by the particular species."

The researchers also concluded that "We therefore suggest that the coding strategy of sensory neurons is not matched to the statistics of natural stimuli per se, but rather to a weighted ensemble of natural stimuli, where the different behavioral relevance of stimuli determines their relative weight in the ensemble."

Machens, Herz, and their colleagues also concluded that their analytical technique could yield broader insight into the evolution of sensory circuitry.

"Our approach presents a systematic way to uncover potential mismatches between the statistical properties of the natural environment and the coding strategy of sensory neurons. In turn, these discrepancies might improve our understanding of the evolutionary design of the specific sensory system," they wrote.


'"/>

Source:Cell Press


Related biology news :

1. Birds brains reveal source of songs
2. Zebra finches remember songs dad sang
3. Cities change the songs of birds
4. New insight into people who see colors in letters and numbers
5. Alaskan puzzles, monitoring provide insight about North Pacific salmon runs
6. New insight into regulation of blood stem cells
7. New insight into autoimmune disease: Bacterial infections promote recognition of self-glycolipids
8. New insights into how Huntingtons disease attacks the brain
9. Gambling monkeys give insight into neural machinery of risk
10. Structures of marine toxins provide insight into their effectiveness as cancer drugs
11. Flies on speed offer insight into the roles of dopamine in sleep and arousal
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/2/2016)... YORK , June 2, 2016   The Weather ... is announcing Watson Ads, an industry-first capability in which consumers ... by being able to ask questions via voice or text ... Marketers have long sought ... the consumer, that can be personal, relevant and valuable; and ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is ... partnership with VoicePass. By working together, ... experience.  Because VoiceIt and VoicePass take slightly different ... engines increases both security and usability. ... excitement about this new partnership. "This ...
(Date:5/3/2016)... VILNIUS, Lithuania , May 3, 2016 /PRNewswire/ ... today released the MegaMatcher Automated Biometric Identification ... deployment of large-scale multi-biometric projects. MegaMatcher ABIS can ... and accuracy using any combination of fingerprint, face ... of MegaMatcher SDK and MegaMatcher ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Cancer ... what they believe could be a new and helpful biomarker for malignant pleural ... Click here to read it now. , Biomarkers are components in the ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... innovative medical technologies, services and solutions to the healthcare market. The company's primary ... various distribution, manufacturing, sales and marketing strategies that are necessary to help companies ...
(Date:6/27/2016)... -- Liquid Biotech USA , Inc. ... Research Agreement with The University of Pennsylvania ("PENN") ... patients.  The funding will be used to assess ... outcomes in cancer patients undergoing a variety of ... to support the design of a therapeutic, decision-making ...
(Date:6/24/2016)... 2016  Regular discussions on a range of subjects including ... two entities said Poloz. Speaking at a lecture ... , he pointed to the country,s inflation target, which is ... "In certain areas there ... common economic goals, why not sit down and address strategy ...
Breaking Biology Technology: