The relationship between mind, brain and body has kept philosophers and scientists busy for hundreds of years. Some of the primary interesting – albeit gruesome – experiments on the role of the body in human consciousness considered life after decapitation.
In 1905, French physician Dr Gabriel Beaurieux believed he had communicated with prisoner Henri Languille after his head had been severed from his body. Writing of the experienceBeaurieux said:
I called in a powerful, sharp voice: “Languille!” I saw the eyelids slowly lift up, with none spasmodic contractions – I insist advisedly on this peculiarity – but with an excellent movement, quite distinct and normal, corresponding to happens in on a regular basis life, with people woke up or torn from their thoughts.
Almost twenty years later, Soviet scientist Sergei Brukhonenko reportedly kept a dog’s severed head alive for nearly six months using a primitive heart-lung machine. Video footage allegedly shows the pinnacle responding to light, sound and citric acid stimuli. But while Brukhonenko’s research could have been a crucial in the event of cardiac surgery – it’s also thought to be faked Soviet-era propaganda.
Consciousness and non-physical properties
Investigations into human consciousness have moved on since these initial observations – though we haven’t got away from decapitation just yet. More recently, nevertheless, neuroscientists have questioned just the way it is that physical matter comes together to make the mind.
In 1995, Dr Francis Crick wrote in his The Astonishing Hypothesis that we’re nothing greater than an “immensely complex collection of neurons”. This theory is a type of reductive physicalism – a philosophical position to which modern neuroscience typically subscribes – that the whole lot in existence is not more than its physical properties.
Again using animal decapitation, though this time with rats, neuroscientists have explored the query of how long brain activity is observed after death – a step forward from investigating consciousness.
In a 2011 experiment, it was reported that decapitated rats’ time to unconsciousness – defined by a decrease in cognitive activity of fifty% – was 4 seconds. The researchers also observed a really large and far later slow wave in brain activity. This was interpreted as what they called a “wave of death” – when all of the brain’s neurons died at the identical time – and maybe, the last word border between life and death.
But some consider that the mind is greater than just the sum of its physical brain cells. A contrasting position to physicalism is the dualist assumption that the physical and the mental are fundamentally different substances.
Furthermore, some philosophers and scientists have suggested that “information would be the key to consciousness”. Consistent with this concept is integrated information theorywhich accepts the existence of consciousness, but controversially implies that anything in any respect could also be conscious – even a smartphone – if it possesses a sufficiently high “phi”: a measure of data in a system which can’t be reduced to that specified by its parts.
From psychological moments to mortality
While I even have ignored many essential details on this fascinating discussion, higher understanding the link between mind, brain and body has been the main target of my very own research, in recent times through the functions of the vagus nerve.
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Higher vagus nerve function (measured and indexed by heart rate variability) supports an individual’s capability for emotion regulation, social engagement and cognitive function. By contrast, impaired vagal function – and lower heart rate variability – may play a job within the onset of depression.
But the vagus nerve doesn’t just affect the mind. Higher levels of vagal function may result in improved glucose regulation, reduced inflammation, and reduced risk of disease and death.
Vagal function can also be known to play a crucial role in brain cognition. It helps to suppress irrelevant and interfering stimuli. Studies have also suggested that the vagus nerve might play a crucial regulatory role over inflammatory processescontributing to diabetes, obesity and heart problems – all of which also impact on cognitive function.
However, little research has been done which looks at how the vagus nerve affects body and mind together. That’s why I teamed up with colleagues to query whether previously reported relationships between vagal function and cognitive performance may very well be explained through a single physiological pathway.
Supporting this possibilitywe observed that impairment in vagal function appears to extend insulin resistance, which contributes to a thickening of the carotid arteries, which in turn adversely impacts on cognitive function. This implies that low vagal function initiates a cascade of antagonistic downstream effects which subsequently result in cognitive impairment.
While easy health behaviours – weight reduction and exercise for instance – may “short circuit” antagonistic effects on brain function, more research into the causal pathways involved is required to find just how the vagus nerve connects the body, brain and mind.
Our research is a primary step into uncovering how the health of the body and mind will be affected by this one nerve. But it’s one step on a path that we hope will develop with our own research into “positive psychology” for people living with neurological disorders.