Scientists discover a ‘consciousness switch’ in the brain

Scientists discover a ‘consciousness switch’ in the brain that triggers waking when it is zapped with electricity and ‘could even bring people out of comas’

A tiny region of the brain has been discovered which works as a switch to activate and deactivate consciousness. 

This area, called the central lateral thalamus, is found deep in the brain and, when triggered with electricity, was found to control consciousness. 

It was tested in macaques and the region is also present in humans. It is hoped the technology could be adapted to help pull people out of comas.  

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A tiny region of the brain has been discovered which works as a switch to activate and deactivate consciousness (pictured). This area, called the central lateral thalamus, is found deep in the brain and, when triggered with electricity, was found to switch on consciousness

A tiny region of the brain has been discovered which works as a switch to activate and deactivate consciousness (pictured). This area, called the central lateral thalamus, is found deep in the brain and, when triggered with electricity, was found to switch on consciousness

WHAT IS CONSCIOUSNESS?  

Consciousness is everything you experience.

But it remains one of the great mysteries of science.

Its existence is irrefutable as every human can attest to it. 

However, it is exceptionally difficult to prove or quantify. 

Consciousness encompasses everything it is to exist and be human.  

There are seven theories as to what makes consciousness a thing focusing on two major aspects, a so-called easy problem and a hard problem. 

The easy problem is the underlying biological processes which control perception,  memory and attention. 

The hard problem is hotly debated. Even its existence is a topic of disquiet among academics. 

This is trying to explain why there is a subjective, first person aspect of consciousness. 

For example, why does banging our funny bone hurt? Why do our bodies not simply register the bodily damage?

This question is exactly what science struggles with.   

Anaesthetised monkeys had an electrode put into their brain that when zapped with electricity switched on their mind and made them alert. 

When it was turned off, the primates went straight back to sleep. 

Researchers sedated macaque monkeys and assessed their brain activity as they slept. 

Yuri Saalmann, an assistant professor at the University of Wisconsin, Madison, said: ‘Our electrodes have a very different design [to most].

‘They are much more tailored to the shape of the structure in the brain we want to stimulate. 

‘They also more closely mimic the electrical activity that’s seen in a healthy, normal system.’

The researchers narrowed down potential targets for a so-called consciousness switch by studying the brains of awake, sleeping and anaesthetised animals.

Imaging techniques honed in on the central lateral thalamus as the most likely location for consciousness control. 

Researchers tested the theory by inserting electrodes into the rain’s of two anaesthetised macaque monkeys. 

Their thalamus was subjected to electricity at a frequency of 50 Hz.

‘We found that when we stimulated this tiny little brain area, we could wake the animals up and reinstate all the neural activity that you’d normally see in the cortex during wakefulness,’ Dr Saalmann says.  

And as soon as the electricity stopped flowing, the anaesthetised macaques instantly went back to sleep.  

Their alertness during this induced period of consciousness was tested to see how they responded.  

A series of beeps were played through speakers with other random sounds interspersed.

The animals responded in the same way that awake animals would respond. 

Imaging techniques honed in on the central lateral thalamus as the most likely location for consciousness control. Researchers used electrodes to stimulate the region with a frequency of 50 Hz and activate consciousness

Imaging techniques honed in on the central lateral thalamus as the most likely location for consciousness control. Researchers used electrodes to stimulate the region with a frequency of 50 Hz and activate consciousness 

‘The overriding motivation of this research is to help people with disorders of consciousness to live better lives,’ says first author Michelle Redinbaugh, a graduate student in the Department of Psychology at the University of Wisconsin, Madison. 

‘We have to start by understanding the minimum mechanism that is necessary or sufficient for consciousness, so that the correct part of the brain can be targeted clinically.’

‘There are many exciting implications for this work,’ she says. 

‘It’s possible we may be able to use these kinds of deep-brain stimulating electrodes to bring people out of comas. 

‘Our findings may also be useful for developing new ways to monitor patients under clinical anaesthesia, to make sure they are safely unconscious.’

The research was published in the journal Neuron.  

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