How the brain responds to visual threats

6 Jul 2018

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Researchers now understand more about how the zebrafish brain perceives and reacts to predators.

Researchers now understand how the zebrafish brain perceives and reacts to predators. This adds to our understanding of how sensory information travels through the brain, and how the brain represents the outside world.

The processing of visual threats by the brain represents an interesting puzzle in neuroscience. Animals ranging from insects to humans try to escape physically in response to a visual threat, but it wasn't previously known how the brain recognises that a stimulus is threatening or why the brain decides to escape.

A window into the brain's response to a threat

Queensland Brain Institute postdoctoral fellow Dr Lucy Heap said the study involved showing zebrafish a large, threatening shape moving towards them and recording the fish's response.

Because zebrafish larvae are small and transparent, the researchers were able to examine activity across the entire brain using microscopes while visual threats were presented.

“This gave us a window into the brain’s responses,” Dr Heap said.

“We found that visual information received from the eyes was broken down into components, such as shapes and brightness.

“These components then needed to be processed separately by two different parts of the brain for the fish to respond appropriately. When a visual threat appeared, cells in a particular part of the brain, the thalamus, were activated," she said.

The thalamas is a region that relays sensory information coming to and from the brain, and helps regulate consciousness and sleep.

“If we interfered with activity in the thalamus, the fish failed to recognise the threat and did not swim away. These results help to complete our picture of how different sensory information travels through the brain, and how the brain represents the outside world," Dr Heap said. 

“Because these functions are abnormal in patients with certain psychiatric disorders, including autism spectrum disorder and schizophrenia, this work sets the stage for deeper studies into the disorders’ basic mechanisms."

Dr Lucy Heap undertook the research, published in Neuron, while undertaking a PhD in the UQ Faculty of Medicine's School of Biomedical Sciences.

 

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