Into oblivion and back

You’re in hospital, lying on a theatre bed, scrutinised by a dozen eyes belonging to doctors and nurses. You hear a few words here and there, most of which are obscure medical terms. There’s a few whispers and then finally someone tells you to relax, puts a mask on your face and asks you to count down from ten to zero. That’s easy, you think. Ten, nine, eight, seven… and the next thing you know is that you’re waking up in a hospital room, feeling drowsy and confused. The operation went well, you’re fully awake but practically unaware of what happened in between you saying “seven” and the present.

Does any of this sound familiar to you? It might do if you’ve ever gone under full anaesthesia. That is because anaesthetics have the power to induce a deep sleep and temporarily shut down those areas of the brain that make you feel aware of where and who you are. In other terms, they make you fall unconscious.

This is why a group of scientists decided to use anaesthetics to shed some light on the deep dark secrets of human consciousness. They chose a brave bunch of healthy subjects, put them under deep anaesthesia, then waited for them to wake up and recorded their brain activity using fMRI and PET scans. To test the re-emergence of a conscious state they asked subjects to respond to a simple command by blinking their eyes. In such way scientists hoped to, quite literally, observe through the scanning machines the reactivation of the neural areas involved with the establishment of consciousness in the brain.

The results were very interesting, but also quite surprising. The areas that were active during the re-emergence of consciousness were mainly the deep core structures in our brain: the thalamus, the hypothalamus, the brainstem, the celebellum and some portions in the frontal and parietal lobes. On the other hand the cerebral cortex, the most outer part of the brain that is much more developed in human beings than in any other mammal, didn’t appear active. This shows that an intermediate state of consciousness, where the subject is able to understand a command and perform a motor action out of their own will, does not require the full activation of the cerebral cortex.

The leading research professor Harry Sheinin at the University of Torku thinks that what the data is suggesting is the emergence of a “primitive” state of consciousness must arise prior to the full restoration of higher order conscious activity.

This means that, in the quest to reveal the biological nature of consciousness, we might have to pay more attention to the most primitive and animal-like areas of our brain because, in evolutionary terms, this is where consciousness is more likely to have developed. This research also opens the doors to a multitude of questions regarding the exclusively human nature of consciousness. If some extremely old parts of our brain that evolved a very long time before man ever walked the Earth can produce a basic state of consciousness, what should we think of other animals? Can we still say that humans are for certain the only conscious creatures? Hopefully the exciting results published in this study will encourage more people to ask these questions… or maybe I should say, more people to invest money in this kind of research!

Reference: http://www.jneurosci.org/content/32/14/4935.abstract

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