In an earlier post, I explained that I was first attracted to the field of neuroscience because it attempts to answer the question “What is humanity?” This question isn’t always the most “practical” to ask in the short-term, especially when the search for disease cures takes up the bulk of research funding. Nevertheless, it’s always refreshing to come across neuroscience research that delves into a somewhat unconventional, yet deeply fascinating aspect of being human. Below, I discuss 3 of my favourite neuroimaging studies which probe at thought-provoking ideas in the domains of Consciousness, Pain, and Sexuality.
1. Consciousness: Reaching out to people in vegetative, “locked-in” states
The first topic relates not so much a single published article, but rather to a large, impressive body of work conducted by Dr. Adrian Owen (formerly of Cambridge University, and now at the University of Western Ontario), who studies disorders of consciousness resulting from brain injuries. When Dr. Owen came to Halifax last summer to give 2 lectures, I didn’t actually know anything about his research. After attending both of his engaging and impeccably-delivered talks at Dalhousie University, I became a bit of a fan of his. This reaction seems appropriate, given that Dr. Owen has become quite the celebrity in the science world because of his startling discovery that functional magnetic resonance imaging (fMRI) technology can be used to communicate with brain-injured patients in vegetative states, who have otherwise been deemed to be “brain dead” and completely unresponsive. Arguing that the proof of a person’s state of awareness is shown by their ability to follow basic commands, Dr. Owen devised a response strategy for vegetative state patients, allowing them to answer “yes” or “no” to a given question. To respond “yes”, the patient was asked to imagine playing tennis. The act of imagining the distinctive swinging motion of a tennis racket reproducibly appeared in the fMRI brain scan as an increased signal originating from the supplementary motor area, which is involved in the control of movements. To respond “no”, the patient was asked to imagine walking through their home, resulting in an increased fMRI signal from the parahippocampal gyrus, which is involved in spatial recognition. This scheme allowed Dr. Owen and his team to ask vegetative state patient specific questions that only the patient and close family knew the answers to. After consulting with the patients’ families, confirmation of the accuracy of the responses cemented the reliability of this communication method. To date, numerous patients have been “found” using this technique.
The revelation that vegetative state patients are still conscious and able to respond to questions uncovered a horrifying truth: there are far more people are experiencing “locked-in” syndrome than had previously been assumed. The implications of this research are tragic in one sense – how many in the past have been grossly neglected after being presumed brain dead? Moral and ethical issues concerning a vegetative state patient’s decision to end his or her own life are also beginning to get caught up in this work – is the patient actually capable of and/or fully able to comprehend making this type of decision? Notwithstanding these concerns, this work offers hope for reaching out to such patients, and for perhaps making their lives more comfortable in some way. For instance, by asking if patients are in pain, small steps towards improving quality of life may be made.
However, there are practical constraints for how far fMRI can go in the clinic for vegetative state patients. Among various limitations, the expense and the size of MRI equipment renders it impractical for having such slow conversations. Consequently, Dr. Owen’s laboratory is currently engaged in efforts to improve the portability, speed, and cost-effectiveness of communicating with vegetative state patients through the use of electroencephalography (EEG) rather than MRI. Since EEG involves the attachment of electrodes directly to the scalp, it is less sensitive to the activity of deeper brain structures such as the parahippocampal gyrus, when compared to MRI. As a result, new response paradigms that will be more amenable to EEG are being developed.
Two things that struck me about Dr. Owen himself is how passionate he is about his research, as well as how skilled he is as a science communicator. Below is a clip of one of his lectures, and is definitely worth taking a look at.
2. Pain: The enhancement of pain relief through religious belief
In 1946, concerning his observations as a U.S. Army doctor in World War II, the anaesthesiologist Henry Beecher wrote,
“There is a common belief that wounds are inevitably associated with pain, and further, that the more extensive the wound the worse the pain. Observations of freshly wounded men in the Combat Zone showed this generalization to be misleading.”
This quotation is a dramatic illustration of how variable pain perception can be between different individuals. The body’s pain pathway is usually depicted in textbooks as a loop: first, a painful stimulus activates pain-sensing receptors (“nociceptors”) in the skin, muscles, joints, or internal organs, and as a result, pain signals are produced and transmitted, first to the spinal cord and then to the brain. Pain is processed and perceived in the brain, which also sends signals back to the spinal cord via a “descending” pathway; this serves to suppress or amplify particular incoming pain signals from the periphery.
The brain is well-known to be the level of the pain pathway that produces the perception of pain. The pain experience is constructed from the widespread activation of various brain regions, including those involved in sensation, emotion, memory, and cognition. But strangely enough (at least from a research standpoint), the brain is arguably the most frequently overlooked player in the pain experience. It’s messy territory, and extremely complicated to examine systematically, especially in humans. Nevertheless, neuroimaging technology has allowed for the brain in pain to be visualized, and many interesting observations have been made as a result. One study that caught my attention in particular is entitled “An fMRI study measuring analgesia enhanced by religion as a belief system”, and was conducted by researchers at the University of Oxford. This study examined the ability of religious images to dampen a religious person’s perception of pain. While religious belief has been anecdotally described as being beneficial for coping with pain, this had previously never been demonstrated in the lab.
As part of the study, the researchers recruited two groups of participants. One group was comprised of 12 highly-devout Roman Catholics who attended mass at least once a week and frequently performed various devotional actions. The other group consisted of 12 people who, denoted as “non-religious”, identified themselves as being either atheists or agnostics. The purpose of the study was two-fold: the researchers wanted to know if one’s religious beliefs could alter the perception of pain intensity from a series of noxious electric shocks (delivered to the hand), and if so, which brain regions were involved mediating in this phenomenon. In an fMRI scanner, participants were asked to rate their perceived pain intensity from the shocks while viewing images of either the Virgin Mary or a similar painting of a woman (control condition). Intriguingly, the religious group reported that viewing the image of the Virgin Mary was more helpful for coping with the pain. Furthermore, during the experiment, these participants appeared to display more activation of a brain area called the right ventrolateral prefrontal cortex. In contrast, the non-religious group didn’t have a preference for either the Virgin Mary image or the control image, and did not experience any pain relief from either of the images. Additionally, non-religious participants did not show activation of the right ventrolateral prefrontal cortex, suggesting that that brain area could be involved in mediating the religious response and subsequent pain relief.
The authors proposed that religious belief, combined with the viewing of a religious symbol, is able to lead to a re-interpretation of the emotional response to pain. Moreover, they suggested that the right ventrolateral prefrontal cortex is involved in this process of “re-appraisal”, during which the perception of pain is modified through an emotional bond with a religious symbol. For me, this study brings up many interesting questions. How would people who were formerly religious or non-religious respond to pain in this experiment? In other words, does changing your mind about religion later in life affect the way that your brain has been wired to respond to pain? And more practically, is this a form of placebo effect that could be used to accompany standard care for religious pain sufferers through the provision of religious objects or imagery? Can other emotionally-charged symbols or objects also modify the experience of pain through a similar mechanism? All of these considerations could certainly be explored in the future using brain imaging.
3. Sexuality: Visualizing the male orgasm
You know that when a paper politely describes a “protocol for ejaculation” and “manual penile stimulation” in the Methods section that it must have been quite an interesting experience for whoever was involved in the data collection process. The last article that I will briefly describe is entitled “Brain activation during human male ejaculation”, and seems frivolous at first glance. However, this research is important because it aids in the understanding and improvement of male sexual health by providing insights into sex-related neural circuits in male brains (heterosexual ones, in this case). Although it was published about 9 years ago, this article has consistently held a spot on the list (updated monthly) of the most-read articles in the Journal of Neuroscience.
In this study, the researchers used positron emission tomography (PET) and MRI scanning to identify regions of the male brain that become activated during ejaculation. They found that a region of the brain called the mesodiencephalic transition zone became highly activated during orgasm, and proposed that areas within this zone that mediate reward, the control of pelvic floor muscles, and sensation, could all potentially be involved in the process of ejaculation. Other areas of the brain involved in emotion and attention were activated, while the amygdala (a center involved in the processing of fear) was actually less active. Overall, this study, which examined healthy male subjects, provided the first framework upon which sexual dysfunctions could subsequently be examined through a neuroscientific lens. Plus, it was also just plain satisfying (pun intended) for everyone’s curiosity.
In summary, the vast improvements in neuroimaging technology have paved the way for numerous fascinating questions in neuroscience to be explored. Whether it’s in consciousness, pain, or even the male orgasm, brain scanning has already begun to revolutionize the ways that we are able to explore our humanity.
Cyranoski, D. (2012). Neuroscience: The mind reader. Nature, 486. Retrieved from http://www.nature.com/news/neuroscience-the-mind-reader-1.10816
Holstege, G., Georgiadis, J. R., Paans, A. M. J., Meiners, L. C., van der Graaf, F. H. C. E., & Reinders, A. A. T. S. (2003). Brain Activation during Human Male Ejaculation. The Journal of Neuroscience, 23, 9185-93.
Wiech, K., Farias, M., Kahane, G., Shackel, N., Tiede, W., & Tracey, I. (2008). An fMRI study measuring analgesia enhanced by religion as a belief system. Pain, 139, 467-76