summary of "10 Unsolved Mysteries of the Brain; What We Know--and Don't Know--About How We Think"

The article “10 Unsolved Mysteries of the Brain; What We Know--and Don’t Know--About How We Think”, by David Eagleman, discusses ten questions about the brain’s activities that have been somewhat answered but are still bewildering scientists. The first question covers how information is coded in neural activity. Neurons produce short “spikes” of voltage (what we call impulses) that travel down the cell’s axon to other neurons. These spikes occur throughout the nervous system and have different causes. Some spikes in the brain, though, are hard to trace to a cause, such as memory and instinct. Scientists believe that these types of information are stored in groups of cells rather than individual cells. However, this is hard to test because electrodes placed in the brain cannot monitor thousands of neurons at once, and a single neuron’s impulses cannot be measured because the average neuron receives impulses from approximately 10,000 other neurons; therefore, when scientists consider the way information is stored in the brain, they look to other possibilities of transfer between cells, such as signaling substances like gases or peptides, rather than just impulses.
When considering the specific topic of memories, their storage, and their retrieval, scientists find complications related to how many different types of memory there are. The brain recognizes short-term memory and long-term memory as well as declarative memories (distinct facts) and non-declarative memories (skills, such as how to ride a bike, etc.), which both fall under long-term memory. Scientists believe that the storing of memories is dependent upon synapses, which are the connections between neurons. When two neurons are used at the same time, the synapse between them strengthens; when they are not used at the same time, however, the synapse weakens. When the synapse is strengthened, an association between the cells is born. For example, an association can form between the smell, warmth, taste, and color of hot chocolate, so that this association can be activated by the smell by itself, causing all of the hot chocolate’s features to be recalled. This aspect of memory is not all there is, though, because memory seems to tend towards remembering relationships between things more than specific details about the things themselves. This is apparent when you sing a song you know in a different key without any trouble, because the brain memorized the relationships between the notes rather than the actual notes themselves. Also, scientists wonder how it is possible that memories that are currently being recalled are more vulnerable to change than when they are stored away in the brain.
Scientists are starting to look with interest at the brain’s “baseline” activity, which is the activity of the brain at rest as well as things in our mind such as emotions, drives, and plans, which are not linked at all to an external stimulus. The resting brain uses twenty percent of the body’s oxygen, which implies that the brain is busy even when we feel that it isn’t. This was verified when scientists found that certain areas of the brain decreased in activity right before the person being studied carried out a goal-related task. These areas were found to be the same regardless of the task, which led scientists to believe that these areas are what carry out baseline activity. Scientists are beginning to believe that external stimuli revise continual internal brain activity rather than cause the activity. This is why it is possible for us to see things while we are dreaming even though our eyes are closed. With this view, the awake state is simply a dream reinforced by stimuli detected by our senses.
Intelligent brains often put time into “practicing” for the future through mental or physical scenarios; therefore, the brain does not just sense and respond to stimuli, but also paints a model of the world and creates rules for how it functions. This can affect not only motor skills, but also perception. It has been shown that the act of seeing uses information stored in the brain as well as information from the retina itself. Scientists today are going back to a belief that scientists such as Aristotle, who lived 2,000 years ago, also believed: the belief that the sole purpose of memory is to make an accurate model and good predictions of the future. Even things remembered about one’s life may point to this purpose.
One cannot study the brain without taking into account emotions. The difference between emotions and feelings is that emotions are distinct physical responses to situations (sweating when you’re nervous, sweating when you’re scared, etc.), while feelings are subject to the situation and accompany the physical effects of emotions (sadness, envy, etc.). Emotions tend to be caused by the subconscious, because people (who were tested) will react to an angry face that is quickly hidden even though they do not remember ever having seen the face. This is similar among humans, birds, and even reptiles. Modern scientists have deduced that emotions are the brain’s way of making a quick summary of one’s surroundings that leads to appropriate reactions, almost like a reflex that tells you to stop whatever you are focusing your brain on and react to the world around you. When your “emotion regulator” is not quite right, the results are emotion disorders such as depression and impulsive violence.
Scientists are mystified when they consider the biological definition of intelligence. What distinguishes a “smart” person from the average person and a human from a monkey, for example? There are many possibilities, and most of them have not yet been tested by experimentation. Short-term memory capacity, the ability to resolve cognitive conflict quickly, the strength of associations between neurons, better reconstruction of information stored in the brain, and superiority of the brain’s model of the future are just a few of the areas which scientists are interested in probing for information about intelligence. Any one of these things (or all of them) could be what distinguishes between different intelligences and what sets humans apart from other animals.
Scientists are stumped when they consider the amazing “editing effects” the brain employs to make occurrences simultaneous. Auditory signals are processed by the brain slightly faster than visual signals, yet your brain can put a sound and a sight together as one. For example, when you clap your hands together in front of your face, the sound of the clap is processed before the sight of the clap; however, the two still seem to happen together even though they were processed at different speeds. This leads scientists to the conclusion that our perception of smooth passage of time is made by the brain; if the brain could not make different sensed phenomena simultaneous, we would not have any sense of time.
All mammals, reptiles, and birds (in general, organisms with brains) need to sleep, and the average human spends one third of his/her life sleeping. This suggests that sleep has a great importance. One of the theories for the reason why we sleep is restoration and saving of energy, but this is disproved when scientists look at the high level of brain activity during sleep. Another theory is that sleep lets the brain “test out” simulations of problem-solving, etc., before using them in the real world. The third theory, which is the most widely-accepted, is that sleep is when the brain stores away in memory what is important and forgets what is unimportant. A test was done on rats in which they were trained to run around a track for a treat while their brainwaves were being monitored. They continued to monitor the rats’ brains during sleep and found that the pattern of activity was exactly the same as when they had been participating in the activities when they were awake. This shows that the brain replays information during sleep that needs to be stored.
The brain is composed of many separate areas with distinct functions, yet all of these areas work together amazingly. The coordination of these areas happens extremely fast compared to the speed of the impulses themselves, which is one hundred-millionth the speed of a signal transmission in a computer; on the flip side, a human can recognize a friend or family member instantly while a computer struggles (sometimes unsuccessfully) to recognize a face. The reason for this is that a brain performs parallel-processing (multi-tasking) and also combines those multiple tasks into a single output incredibly fast. While computers can parallel-process, they are slow to analyze the resulting information. In addition, there is no set area in the brain that is responsible for putting together multiple pieces of information; rather, all the areas of the brain interconnect to form a complex network, which is why our brain processes information so much faster than a computer.
Trying to explain consciousness is difficult for scientists because it is trying to find what “clicks on” when you wake each morning that is not there when you are sleeping. It is known that consciousness emerges from the physical material of the brain because even very small changes to the brain have great effect on our subjective experiences. The only way that scientists know of to study consciousness is through experimentation. In one such experiment, test subjects see the image of a house in one eye and the image of a cow in another. Instead of mixing the images together and seeing a “house-cow”, the brain perceives one, then sees the other, then back again so that the brain’s conscious experience changes as the stimuli stay the same. This experiment leads scientists to wonder what areas of the brain correlate with what we consciously perceive and why.
The complexity of the brain is astounding and awe-inspiring. The questions posed in this article are just some of the many questions we have about the functioning of the human brain. Looking at this information, I find it very hard not to look towards an Intelligent Designer who created the vast workings of our bodies. The details of how our brains work are too many to have occurred by chance, and I am sure that many of the questions scientists have cannot be answered by scientific means alone. For example, the question of how our brains distinguish morals and a higher purpose (which was not asked in this particular article) can only lead back to the fact that we were made in God’s image and have His Spirit in us. I am amazed by God’s creativity and attention to detail that are exhibited in the structure and function of the human brain. doc10092007112239.pdf