Summary: Adult worms can trigger two conflicting memories—mating and starvation—when encountering the same smell, but only one influences their actions. A study conditioned worms to associate the smell with both positive ( mating ) and negative ( starvation ) experiences, revealing that mating associations overrode avoidance behavior.
In accordance with this accommodating memory processing, the brain gives rewards precedence over punishment in some situations. The results provide insight into memory-driven behaviour and provide an investigation of PTSD’s pathological processes.
Important Information:
- Man worms can trigger contradicting memories, but only one dictates conduct.
- Positive ( mating ) memories can override negative ( starvation ) associations.
- PTSD and different neurocognitive research may be informed by insights into storage control.
Origin: UCL
Two opposing memories can both be activated in a spider’s mind, even if only one storage constantly drives the animal’s behavior, finds a new study by UCL researchers.
The researchers investigated what happens when a worm smells an odour that has been linked to both good experiences ( mating ) and bad experiences ( starvation ) in a paper published in , Current Biology, showing how sex drive can sometimes outweigh the need to eat when determining behavior.
The researchers wanted to know how an individual’s brain determines whether a given situation is good or bad, and how this affects its reaction.
They discovered that adult worms can have both positive and negative organizations with an odour by heating them to have both memories, but only one of them will have an impact on how they act.
The researchers claim that their findings can be substantiated in order to understand how medical conditions like post-traumatic stress disorder ( PTSD ) affect behaviors and emotions because memories that should be latent ( dormant ) are still a problem for influencing behavior and emotions.
We were looking into the adult worm’s brain to grasp the biological or molecular methods that affect how a particular storage affects behavior, according to lead author Dr. Arantza Barrios (UCL Cell &, Evolutionary Biology ). Our brains can change and override earlier associations, which is a crucial component of learning.
Co-first artist Dr , Susana Colinas Fischer , (UCL , Cell &, Evolutionary Biology ) added:” By understanding what a pretty little insect is thinking, we are able to learn more about the processes underlying our own more complex thinking habits”.
The investigation was undertaken with male , C. elegans , tapeworms, a species of insect 1mm in size that is very commonly used as a model species in clinical studies. The researchers claim that the worms were exposed to an innately appealing odor similar to that of a delicious dinner.
The researchers monitored the worms ‘ behavior and brain activity through a series of experiments that altered their preferences for the odour.
Aversive conditioning, in which the worms experienced the odour together with a punishment of starvation, overpowered the worms ‘ instinct to approach it.
The researchers then attempted to override this learned avoidance by using additional conditioning, which included a female mate and some sexual encounters, to create a new positive relationship between the male worms and the odour.
A particular neuropeptide ( a chemical messenger in the brain ) that stores the memories of both the starvation and mating associations with the odour was the focus of the analysis ‘ discovery of a circuit of brain cells that represents both positive and negative associations with previous encounters.
Both memories were activated in the brain in worms that had been conditioned to associate the odour with starvation and mating. However, the mating association, which is the only one, managed to keep the worm from oozing.
Even though both memories remained intact, the researchers claim that this suggests that the prospect of a mating reward outweighs the prospect of a starvation punishment. The worm no longer avoided the smell, but the negative memory of starvation was still present in the brain’s activity.
Co-first author Dr , Laura Molina-García , (UCL , Cell &, Developmental Biology ) said:” We found that even in an animal with a very small brain like that of a roundworm, two conflicting memories can both be activated at the same time, with one memory impacting behaviour and one memory remaining latent.
An animal’s brain learns and adapts to new information by flexibly representing something that is both good and bad.
We hope to inform research into treating the maladaptation of this process, such as PTSD, by learning how some memories can override other conflicting memories.
Funding: The research was supported by the Royal Society, Wellcome and Leverhulme Trust.
About this news about neuroscience research and memory
Author: Chris Lane
Source: UCL
Contact: Chris Lane – UCL
Image: The image is credited to Neuroscience News
Original Research: Open access.
Arantza Barrios et al .’s” Conflict During Learning reconfigures the neural representation of positive valence and approach behavior.” Current Biology
Abstract
The neural representation of positive valence and approach behavior is reconfigured by learning conflict.
Punishing and rewarding experiences can alter the sensory quality of animals and cause avoidance or approaching. Often, however, a stimulus is encountered with both positive and negative experiences.
How is this contradictory information embodied in the brain’s decision-making process?
We address this question by dissecting a circuit for sexual conditioning in , C.  , elegans. In this learning paradigm, an odor is conditioned with both a punishment ( starvation ) and a reward ( mates ), resulting in odor approach.
We discover that different neurons release the neuropeptide pigment dispersing factor 1 ( PDF-1 ) when it is activated by it in both positive and negative experiences. The circuit for odor processing is made up of distinct memories as each experience.
Despite both displaying approach, this causes the sensorimotor representation of the odor to differ between naive and sexually conditioned animals.
Our findings demonstrate that a stimulus’s positive valence is flexibly represented within the circuit in response to the experiences and predictions made with it in addition to any single neuron class ‘ activity.
