In this blog post, we will examine how the saying “love is blind” can be explained by brain science through fMRI research.
The phrase “Love is blind, and lovers cannot see the pretty follies that themselves commit” from Shakespeare’s comedy “The Merchant of Venice,” Act II, Scene VI, expresses how men and women fall in love as if they were blind. When we fall in love, we are said to be “blinded by love” and unable to see the true nature of the other person. Human emotions and behaviors originate from the brain. Does the brain really work in such a way that we become blind when we fall in love? The brain responses that writers in the days before the concept of “brain science” existed included in their works as the result of their careful observations of human beings have been proven by fMRI (functional magnetic resonance imaging), an advanced form of MRI, which is the culmination of modern medical imaging technology.
To understand fMRI, it is necessary to first understand the principles of MRI and the background behind its development. Starting with the discovery of X-rays by Röntgen in 1895, various medical imaging technologies such as CT, MRI, and ultrasound appeared in the 20th century. MRI, in particular, has undergone rapid development since the late 1970s due to its unique advantages, including its use of non-ionizing radiation, which makes it harmless to the human body. MRI obtains images using hydrogen atoms inside the human body instead of radiation. It is well known that water accounts for the largest percentage of the human body. Water (H2O) is a molecule composed of two hydrogen atoms and one oxygen atom. Therefore, hydrogen is the most abundant element in the human body, and all body tissues contain hydrogen atoms, although the number varies. Normally, all water molecules are randomly arranged in different directions, but when exposed to a magnetic field above a certain level, they align in a certain direction. Therefore, the principle of MRI is to obtain images by measuring signals from hydrogen atoms arranged in a large magnetic tube containing the human body. This is similar to the principle of counting people, where it is easier to count accurately when they are arranged in a regular pattern rather than scattered randomly.
MRI is often compared to X-rays and CT scans because they all produce images of the inside of the human body. X-rays and CT scans are imaging technologies that use X-rays, which are reflected by solid objects and are therefore used to show bones, but cannot be used to see human tissue or organs because they pass through them. X-rays cannot pass through the thick, hard bones of the skull, so they were useless for viewing the brain, but MRI made it possible to obtain images of the brain inside the skull. Another advantage of MRI is that it can produce a wide variety of images depending on how the images are obtained. Functional magnetic resonance imaging (fMRI), considered one of the most revolutionary methods combining the two advantages of being able to obtain images of the brain inside the skull and the diversity of imaging methods, appeared in 1990. Seiji Ogawa’s group at Bell Laboratories in the United States discovered that MRI produces different images depending on the degree of oxidation of hemoglobin in the blood. When a part of the brain is activated, blood flow to that part temporarily increases. At this time, not only does blood flow increase, but oxygen supply also increases, and the action of a molecule called hemoglobin is necessary for oxygen to be supplied to brain cells through the blood. This means that more blood contains more oxidized hemoglobin. The following conclusion can be drawn from the above facts. By capturing the moment when hemoglobin temporarily increases in the blood vessels passing through the brain tissue that is actively working, it is possible to visualize information about which parts of the brain are actively working, as if it were a “map.”
With the spread of fMRI, there has been an explosion of experiments using fMRI to study the mechanisms of the brain and cognitive processes. These experiments have different themes but follow the same process, which is to compare brain images taken when a stimulus is applied and when no stimulus is applied to understand the mechanisms of brain function. The Swami group studied how the brain is activated by showing a series of photos of attractive men and women mixed with photos of men and women of average appearance to men and women who are in love and those who are not. In the brain images of couples in love, there was no significant difference between the attractive and ordinary photos, but the brains of single men and women were more active when they viewed the attractive photos. The results of the experiment scientifically demonstrate that when you are in love, you become “blind” and cannot see anyone but your beloved. Subsequently, Professor Zeki of the University of London announced that when people fall in love, the function of the prefrontal cortex, which controls judgment, deteriorates, causing judgment to become clouded and people to become “blind.”
Expressions of love described in literary works were written before the establishment of brain science research, but they accurately reflect brain science theory. And now we live in an age where we can see the workings of love with our own eyes. The secrets of the brain that still need to be solved await future generations of scientists, but MRI, the most important machine for solving these mysteries, also has homework to do. In fact, MRI machines are expensive and mostly used for medical purposes, so they cannot be freely used for research. In addition, even the slightest movement inside the machine causes significant noise in the images, making it almost impossible to take images of children or people with claustrophobia. Nevertheless, the potential of MRI and the imagination of countless researchers will lead to countless amazing discoveries in the future.
