Mice fooled by optical illusions: New insights into brain function

summary: Mice are susceptible to a visual phenomenon known as neon color spread, a commonly seen optical illusion in humans. This study utilized both electrophysiology and optogenetics to investigate how neurons at different levels contribute to brightness perception.

This breakthrough finding confirms that such illusions can be a valuable tool in neuroscience, providing insights into sensory processing and the hierarchical functioning of neurons. The findings support the use of mice as a viable model to study complex perceptual processes and have the potential to advance our understanding of consciousness.

Important facts:

1. innovative technology: This study is pioneering in that it simultaneously uses electrophysiology and optogenetics to study how optical illusions are processed by the brain.
2. Nerve layers involved: This study shows that V1 neurons respond to both illusory and non-illusory stimuli, whereas V2 neurons enhance the illusion by modulating V1 activity, highlighting their role in brightness perception. It turns out that.
3. Implications for neuroscience: Demonstrating that mice can perceive optical illusions similarly to humans suggests new possibilities for using animal models to study the neural mechanisms of perception and consciousness.

sauce: University of Tokyo

A study has shown for the first time that a certain illusion of a spread of neon colors works on mice.

This study is also the first to combine the use of two research techniques called electrophysiology and optogenetics to study this illusion.

The results of experiments in mice settle a long-standing debate in neuroscience about which level of neurons in the brain is involved in the perception of brightness.

We are all familiar with optical illusions. Some are new and some are all around us. Even when we look at the screen in front of us, we are tricked into thinking that the color is white.

What you're actually looking at is packed with so many red, green, and blue elements that it gives the impression of being white. Another example is a wheel or propeller that rotates at high speed. This can appear to momentarily reverse direction while accelerating at full speed.

Either way, you might be surprised to learn that optical illusions are not only fun to look at, but they're also useful tools for learning about the eyes, nerves, mind, and brain.

Associate Professor Masataka Watanabe of the University of Tokyo's Department of System Innovation is on a mission to further understand the nature of consciousness.

This is a vast subject area, so of course there are many ways to explore it, but in particular he uses optical illusions.

His latest research investigated whether certain illusions that work on humans also work on mice. And in the end, that's what happens. But why is this important?

“It's useful for neuroscientists like me to know that this type of illusion, called the neon color diffusion illusion, works not only in humans but also in mice. “It means it can serve as a test subject,” he said. Mr Watanabe.

“To really understand what's happening in the brain during perceptual experiences, we need to use specific methods that aren't available to humans.

“These include electrophysiology, recording neural activity with electrodes, and optogenetics (where pulses of light enable or disable specific neurons to fire in the living brain).”

Watanabe's experiment is the first of its kind to simultaneously utilize both electrophysiology and optogenetics in animal subjects exposed to neon color diffusion illusions, allowing his team to determine which We were able to precisely observe which structures were responsible for the processing. A fantasy.

“When a visual stimulus reaches the eye, it is carried by nerves to the brain and is received by a series of neuron layers called V1, V2, etc. V1 is the first and most basic layer, and V2 onwards are the higher layers. ” says Watanabe.

“The role that higher levels play in brightness perception has been a long-standing debate in neuroscience, and studying it has been challenging.

“In experiments with mice, we found that neurons in V1 responded not only to the illusion, but also to non-illusory versions of the same types of patterns shown.

“But only when we showed mice the hallucinatory version did we find that neurons in V2 also play an important role. That is, neurons in V2 play an important role in regulating the activity of neurons in V1, and neurons in V2 play an important role in regulating the activity of neurons in V1. It has been shown that this actually plays a role in the perception of brightness.

This experiment showed that mouse models are effective in this field of neuroscience. Watanabe hopes this is just the beginning and that experiments like this will help his ambitious goal of understanding the neural mechanisms of consciousness.

Funding: This research was funded by the Max Planck Society and the Helsinki Institute of Life Sciences at the University of Helsinki (Northern Territory).

About this visual neuroscience research news

author: Rohan Mehra
sauce: University of Tokyo
contact: Rohan Mehra – University of Tokyo
image: Image credits are: andy parkinson (CC with SA 3.0)

Original research: Open access.
“Illusion of brightness promotes neural responses in primary visual cortex under top-down modulation” by Masataka Watanabe et al. nature communications

abstract

Illusion of brightness promotes neural responses in primary visual cortex under top-down modulation

The illusion of brightness is a powerful tool for studying vision, but its neural correlates are poorly understood. Based on the human paradigm, we presented mice with an illusory drifting grid.

Primary visual cortex (V1) neurons responded to illusory gratings consistent with their directional selectivity to real gratings and tracked the spatial phase offset between illusory and real gratings.

In accordance with the theory that illusory processing requires feedback from the higher visual cortex (HVA), the illusory response was delayed compared to the real grating.

We support this theory by showing decreased V1 responses to the illusion, but not to the real grating, after optogenetic inhibition of HVA. Finally, we used pupillary response (PR) as an indirect perceptual report and showed that mouse PR matches human PR for perceived luminance changes.

Our findings resolve the debate as to whether V1 neurons are involved in illusory processing and highlight the involvement of feedback from the HVA.