Understanding the Neuroscience and Philosophy of Consciousness

By Yusuf Lenfest

Think of the last few times you’ve had a very lifelike dream. Running, reading, or having conversations with others, are all activities that might happen during a particularly vivid dream. But would this be considered consciousness? Surely being in a state of sleep is not the same as being in a waking state; but if you are able to communicate, to attend a lecture, perhaps even to give a lecture whilst you sleep, what does this mean in terms of your brain’s activity? Very deep in the sleep cycle, a person may not respond immediately to touch or sound or any other sensory stimulus. That is, they may not wake up, though it cannot be ruled out that an external stimulus might influence the sub-conscious mind and hence their dream. We’ve all had the experience of hearing an alarm “in our dream” which is really our real alarm, yet our mind re-interprets it and incorporates it into our dream until we regain consciousness, i.e., wake up. What if you couldn’t wake up from your unconscious state? And if so, what would this mean for how your brain processes your thoughts? In effect, what would it mean for your lived reality if you could only live in your mind?

Beyond being a fun thought experiment, these may be some very relevant questions now that doctors have treated a vegetative-state patient with an experimental therapy leading him to regain partial consciousness.

It was reported yesterday in National Geographic, Popular Science, the Guardian, and elsewhere that a 35-year-old man who had been in a persistent vegetative state (PVS) for 15 years has shown signs of consciousness after receiving a pioneering therapy involving nerve stimulation. The French researchers reported their findings to the journal Current Biology. Led by Angela Sirigu, a cognitive neuroscientist and director of the Institut des Sciences Cognitives Marc Jeannerod in Lyon, France, a team of clinicians tried an experimental form of therapy called vagus nerve stimulation (VNS) which involves implanting a device into the chest designed to stimulate the vagus nerve. It works by giving off miniscule electrical shocks to the vagus nerve, a critical brain signal that interfaces with parasympathetic control of the heart, lungs, and digestive tract.

So again, what does it mean to be conscious?

The attempt to define consciousness has a long history. Descartes’ theory of the pineal gland being the seat of the human soul can now safely be discarded but, although not readily admitted, the concept of dualism is not so easily escaped: i.e., whether there are two kinds of substance, the mental and the physical, that somehow interact. Modern notions of the soul range from the negative (there isn’t one) to the agnostic (we don’t really know, and perhaps can’t know) to those who affirm that the soul exists. Interestingly, this last category is divided into still further categories, with some taking a staunchly dualist stance—namely many Christian theologians and thinkers—whereby the soul is held to be immaterial. Whereas others view the soul atomistically. And yet another group, many metaphysicians and some theoretical physicists, posit neither the existence of a “soul” per se nor hold religion to be the sine qua non of existence, rather they posit that God is necessary for a metaphysical system. Alfred North Whitehead’s notion of process philosophy is one of the more coherent recent examples of this. Islamic philosophers such as Abu Hamid al-Ghazali (d. 1111) and Nasr al-Din al-Tusi (d. 1274) also held various views on the issue of the soul, consciousness, and science—the latter having forwarded a basic theory for the evolution of species almost 600 years before Charles Darwin was born. Interestingly, while the Arabic word for the physical heart is qalb, there is another word, fu’ad, which can signify the “metaphysical heart,” i.e. the mind or consciousness. In many ways, the body/soul debate has now evolved into the brain/mind debate.

Without delving into the complexities of metaphysical doctrine, even if we hold, for the sake of argument, that there is no soul, it does not diminish the ethical implications of what treatment might mean for those in a PVS. On the one hand, doctors have an ethical obligation to do everything in their power to preserve and restore the health of a patient; on the other hand, we have to consider the symbiosis between brain and body, and what it might mean for someone in a vegetative state. That is, in the same way that thinking (or dreaming) about something stressful can cause an elevated heart rate and increased perspiration and blood pressure, so too is it possible for external stimulus to change the neurological response, for better or for worse.

It is important to note that people in a vegetative state aren’t considered to be brain dead. Many spontaneously cry and smile. They open their eyes and can swallow when being fed. Their brains often have recognizable sleep-wake cycles, and exhibit other signs of partial consciousness. Insofar as these individuals don’t respond to external stimuli in the way that a sleeping person might wake up, another pressing question therefore might be whether these individuals are experiencing dreams or other sub-conscious states, and if so, whether these states are pleasant or distressing?

Without subjective testimony, it is difficult to make any conclusions about the quality of life for someone in a vegetative state, or what they experience on a daily basis, let alone the lived reality across the entire span of a PVS. Technology and medical advances permitting, would waking from a PVS simply be like waking from a long slumber, wherein you recall some dreams, but forget most? Our intuition likely works on the assumption that individuals in vegetative states would wish to be sustained and, hopefully, brought back to full consciousness. Dr. Nicholas Schiff, a neuroscientist at Weill Cornell Medicine and NewYork-Presbyterian who also researches consciousness cited that in the United States there are an estimated 50,000 patients living in a vegetative state; there are another 300,00 in a minimally conscious state. Yet according to doctors and researchers, they are unaware of their surroundings and are not able to communicate or respond to external stimulation. Moreover, in contrast to a coma, from which it is possible to recover and regain full awareness, many experts consider any vegetative state that persists beyond 12 months to be permanent.

Vagal nerve stimulation may change that, as in the case above. Some, like Andrew Cole, a neurologist at Harvard Medical School, have cautioned about assigning too much to this case before data are interpreted more comprehensively and further tests are carried out. As reported in Science magazine, “neuroscientist Nicholas Schiff of Weill Cornell Medicine in New York City agrees with Cole that a study of a single patient is not enough to make sweeping conclusions about the therapy, but he is optimistic about the treatment’s promise.” The challenge now is both time and money, since researchers must replicate  VNS therapy on a number of patients with a variety of controls to produce more conclusive evidence of the treatment’s benefits. Nevertheless, Sirigu and her colleagues’ findings are promising:

After one month of stimulation, when intensity reached 1 mA, clinical examination revealed reproducible and consistent improvements in general arousal, sustained attention, body motility and visual pursuit.

We should be optimistic about these findings too. If successful, the question then becomes to what extent consciousness can be restored and, furthermore, whether it possible for someone to wake up from a permanent vegetative state and live a normal life. The implications are of course far-reaching, and it may raise new ethical, religious, and even legal considerations—such as patients’ rights and caregivers’ duties, or considerations about legal personhood and religious notions of the sacred inviolability of the human. Beyond the continued commitment and care that doctors and family members provide, these findings are potentially very important because they strike at the root of what we assume and think we know about the human being, and it causes us to question both how to define, and how to understand, consciousness.