‘Giving up’ is wired into the brain, suggests new research
- Shruti Sundar Ray
- Nov 25, 2019
- 2 min read
A group of researchers at the Howard Hughes Medical Institute has discovered that repeated failure induces a passive state in the brain cells of zebrafish
Larval zebrafish will stop trying to keep swimming when they perceive that they are unable to move, is the finding of a study conducted by researchers at the Howard Hughes Medical Institute. The study, published in the journal Cell, finds that glial cells in the brain, whose functions are not completely understood, may have an important role to play in this process of ‘giving up’.
This new research is a step in the direction of a better understanding of the human brain and what controls human behaviour. ‘Giving up’ is common across the animal kingdom and zebrafish, the lab rats of the aquatic world, were chosen for the experiment.
Perception of failure induces a passive state
The fish were placed in a virtual reality environment, where they were surrounded by screens that allowed the researchers to control what the fish could see. The fish would attempt to swim forward but the video projected on the screens would make them think they were moving backwards. After repeated attempts, the fish would suddenly stop swimming. The researchers conclude that this sudden ‘state of passivity’ is a result of the perception of failure since the fish were made to think that they were not moving forward.
“Giving up is a very important thing for animals to be able to do,” said neuroscientist Misha Ahrens, who headed the research team in a press release. Animals would exhaust their energy unnecessarily if they continued to repeat a behaviour that did not yield the desired result.
New understanding of brain cells
The researchers used a calcium-based whole-brain imaging technique, developed at the Howard Hughes Medical Institute itself, to study the brain activity patterns of the zebrafish. They wanted to understand which neurons showed greater activity during the behavioural shift. But, surprisingly, the activity was highest in certain non-neuronal or glial cells called radial astrocytes or astroglia.
The role played by the astroglia was looked at more closely. When the scientists wiped out these cells using a laser, the fish continued to swim forward and no sudden stopping was observed. Moreover, when the glial cells were artificially activated, then the fish were induced into a passive state. Thus, the failure-induced passivity could be directly attributed to the astroglia.
This finding is especially significant since the functions of glial cells are not fully understood. Until a few decades back, the thinking within the scientific community was that these cells were only a kind of ‘glue’ that held together and insulated neurons.
The team also found that another type of brain cell called noradrenergic neurons were also activated right before the fish gave up. This could indicate that they play a role in detecting failures and sending signals to the astroglia. The astroglia, upon receiving the failure signals, are induced into passivity, causing the fish to ‘give up’.
With new research, like the present study, our understanding of the complexities of the human brain is only getting better.
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