Hibernation has always been a recurring theme in science fiction with examples found in the novels of William Gibson and Bruce Sterling. We spoke about it with Matteo Cerri, a researcher in the Department of Biomedical and Neuromotor Sciences at the University of Bologna.
Which scientific discoveries have given rise to the idea of hibernation with regard to space and travel?
The idea of creating a procedure which would allow humans to hibernate is not new, especially considering the important clinical implications linked to this possibility. However, for a long time the theoretical framework which would have allowed us to take the necessary steps to get there was missing. As often happens in the world of basic research, studies can result in unexpected consequences and scenarios. On the other hand, if we were to plan every discovery, things would begin to feel stale with the feeling of already having been done. In our case everything originates from a group of American researchers - particularly one Professor Shaun S. Morrison - who patiently studied the way in which the brain regulates and controls heat production in the body. During those years, the aim of the research was to find a cure for obesity which is a growing problem in the western world. The idea was simple: activate the consumption of the body’s energy to consume calories and therefore lose weight. It was only after a decade of work that the idea of attempting to reverse this process - i.e. switch off the body’s consumption of energy - came to mind. In the beginning, the applications were thought to be purely clinical. In fact, for many conditions, from strokes to heart attacks, inducing a state of suspended animation would be clinically very important in that the damage caused by the illness could be greatly reduced. This was then applied to space and considered by space agencies which eventually opened a door to some extremely innovative scientific research.
In what way could hibernation - a disruption of normal brain activity - change the common notion of time during a space journey?
This is a difficult question to answer as the human neural substrate responsible for the perception of time is not well known. Based on the brain activity of animals, both those which hibernate naturally and those for whom the process has been pharmacologically induced, it can be said that neuronal time probably passes more slowly. To clarify, this does not mean that changes are observed in the physical nature of time. It does mean that whatever mechanism used by the brain to process the passing of time will work more slowly, therefore changing our perception.
Among the causes of this slowing down, there is certainly the so-called Q10 effect, an effect which describes how the speed of biochemical reactions at the base of life is proportional to temperature. In other words, in colder living cells reactions occur more slowly, a bit like a film in which the frames slow down gradually on the screen to cool the projector.
However, would we be able to perceive this slowing down? This is even more difficult to predict. In order to be able to accommodate the consciousness, the structure would need to possess certain characteristics. Among them, the ability to accommodate a certain amount of integrated information, which is measured by a number called Φ (Phi). The higher Φ is, the more “supportable” the consciousness of that structure is. Does Φ change during hibernation? It probably decreases significantly. In fact, during hibernation the connections between neurons - the synapses - which are normally at the base of the cortical connectivity and which generate a high Φ, are reabsorbed. In other words, the neurons disconnect, thus transforming the complex universe of the neural network into a “simple” set of neurons. It is therefore possible that a person in hibernation would no longer be able to experience a flow of consciousness to which we are accustomed.
What physical and physiological repercussions would a state of hypothermia have on the human body?
The study of hibernation and its peculiar physiology has revealed many interesting phenomena, the understanding of which, once applied to humans, will be of great benefit in many clinical conditions. Here is a brief description of some of these phenomena:
1) The maintenance of muscle tone, the lack of mineral loss in bones and elevated radiation protection. How exactly this works is not yet known but this last characteristic is of great interest in relation to both space travel and with regard to the use of more evolved anti-tumour radiation therapy protocols.
2) The synaptic modifications. During hibernation the cerebral cortex undergoes a “functional disconnection” which is similar to that which occurs in Alzheimer’s disease. In hibernating animals however, these changes rapidly return to normal during the process of awakening.
3)During hibernation the immune system undergoes a major overhaul. For example, lymphocytes migrate from the blood to the lymph nodes, leaving the body in a de facto state of immunosuppression. This finding could lead to new approaches to inflammatory diseases using immunosuppression from hibernation.
4)During hibernation cancer cells do not proliferate and resume their activity upon reawakening. To explore the workings of this powerful action and how it could be used would certainly be of great interest.
The implementation of this discovery could mark the end of the world as we know it today. How would it affect our daily lives?
The ability in humans to hibernate would probably not change our conception of the world, at least in the short term. At the moment we do not know how long a state of suspended animation could be maintained. If we look at the natural world, mammals that hibernate do so for up to nine months, but there are some animals that can remain in a quiescent state for years. A multi-year dormancy is currently a little beyond our means but obviously this could change. If, however, the possibility to remain in a state of suspended animation for decades or centuries were to be developed, then it would pose questions and issues which would significantly change the world as we know it. For example, we could induce hibernation in criminals with the possibility of later freeing them as if no time had passed, should they be found innocent. However those who were in fact guilty would find themselves not having to endure the penalty time, would this be acceptable? And what would the rights of a person in hibernation be? For what reason should they be wakened? Who would pay the costs of the process? These sort of questions accompany all technological revolutions.
Frame from Avatar by James Cameron.