Navigation Links
Researchers identify neurons that assign value during learning

By using an experimental trick to activate certain sets of neurons and effectively substitute activation of these cells for positive or negative experiences, researchers have been able to identify neurons in the fruit fly Drosophila that are responsible for assigning value to stimuli during so-called associative learning. The findings, which advance our understanding of how, at the cellular level, we learn to associate cues with positive and negative experiences, are reported by Andre Fiala and colleagues at the University of Würzburg in Germany and appear in the September 5th issue of Current Biology, published by Cell Press.

During associative learning, animals learn to change their behavior in response to a particular stimulus that would otherwise have a neutral influence on behavior. For example, if an animal such as a fruit fly learns to associate a particular odor with a punishing stimulus, the odor itself can become repulsive. Conversely, an odor associated with a reward can become attractive. Despite its relatively modest brain complexity, the fruit fly larva is able to perform such associative-learning tasks. Because of its neuronal simplicity and the fact that it can be genetically manipulated, the fruit fly offers a favorable study case to address a principal question in the field of learning and behavior: Which neurons attribute attractive or aversive values to so-called neutral stimuli, such as odors, in the course of associative learning?

Past work had indicated that certain neurotransmitters played key roles in assigning attractive or aversive values to neutral stimuli--for example, neurons expressing dopamine are required for aversive learning, whereas neurons expressing another neurotransmitter, octopamine, are required for appetitive learning (association of a stimulus with a reward). However, it was unclear whether a common set of neurons were responsible, or whether attractive and aversive values were assigned to neutral stimuli by independent sets of neurons.

To tackle this question, the researchers engineered transgenic fruit flies that express in distinct nerve cells a special ion channel, "channelrhodopsin-2," whose activity is light-sensitive (the protein is normally found in green algae). As a result of expressing channelrhodopsin-2, neurons could be activated simply by illuminating fruit fly larvae with blue light. This tool allowed the researchers to test whether such an activation of certain neurons can actually substitute for external stimuli--for example, reward or punishment--in an associative-learning experiment. The researchers found that if an odor is presented while a group of dopamine-releasing neurons are experimentally light-activated, the larvae learn to avoid this odor in a later test, despite the fact that no negative stimulus was presented to the larvae along with the odor. Conversely, if an odor is presented while a different group of neurons--releasing octopamine and/or tyramine--are experimentally light-activated, the odor becomes attractive. These findings demonstrate that antagonistic subsets of neurons are responsible for assigning positive or negative values to odor stimuli. It will be of interest to see whether this principal concept of antagonistic neuronal populations mediating positive or negative values during learning holds true for much more complex mammalian brains as well.


'"/>

Source:Cell Press


Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/13/2017)... According to a new market research report "Consumer ... Administration, and Authorization), Service, Authentication Type, Deployment Mode, Vertical, and Region - ... to grow from USD 14.30 Billion in 2017 to USD 31.75 Billion ... ... MarketsandMarkets Logo ...
(Date:4/11/2017)... BROOKLYN, N.Y. , April 11, 2017 /PRNewswire-USNewswire/ ... identical fingerprints, but researchers at the New York ... University College of Engineering have found that partial ... fingerprint-based security systems used in mobile phones and ... previously thought. The vulnerability lies in ...
(Date:4/5/2017)...  The Allen Institute for Cell Science today announces ... portal and dynamic digital window into the human cell. ... application of deep learning to create predictive models of ... a growing suite of powerful tools. The Allen Cell ... publicly available resources created and shared by the Allen ...
Breaking Biology News(10 mins):
(Date:8/16/2017)... and OXFORD, England , Aug. ... -based consortium for biotech executive search and leadership development, and ... Healthcare sectors, have created an exclusive alliance that enables clients ... "For our clients here in ... provides unparalleled access to a diverse population of leadership talent ...
(Date:8/15/2017)... ... ... Any expert in stem cell research or stem cell medicine knows well the ... Despite their essential roles in human health and regenerative medicine, adult tissue stem ... this purpose also tag other, more abundant, non-stem tissue cells ( See 2017 Cell ...
(Date:8/14/2017)... Linda, Ca (PRWEB) , ... August 14, 2017 ... ... for poorly characterized and performing antibodies. Key researchers in the antibody community have ... proper characterization and consistency for antibodies in the laboratory. , The ...
(Date:8/11/2017)... ... August 11, 2017 , ... Algenist continues to disrupt the skincare industry ... never before. , Collagen is the key structural element skin needs to maintain ... which include: , First to market with proprietary collagen ...
Breaking Biology Technology: