Brainy Behavior

Mo at Neurophilosophy posted a great video of Deep Brain Stimulation (DBS) surgery being performed on a man with essential tremor, while he plays the banjo. As with most brain surgeries, the patient was awake, alert, and talking. The doctors had him play the banjo so they could fine tune (pun intended) the electrode placement in order to have the best response.

The human brain is a wondrous thing. It is the single most complex organ on the planet. It sits atop the spinal cord. Gazing upon the brain, one sees four main distinct areas – two roughly symmetrical hemispheres, a cerebellum stuck up underneath the posterior part of the brain, and a brainstem sticking out and down from the middle of the brain. Each cerebral hemisphere is divided into four visible lobes: frontal, temporal, parietal, and occipital. The frontal lobes jut out at nearly a 90 degree angle from the spinal cord and are the largest part of the human brain. The temporal lobes stick out the sides of the brain, like thumbs pointing forward at the side of a fist. The parietal lobes are harder to distinguish. They are just posterior to the frontal lobes and dorsal to (above) the temporal lobes. The occipital lobes are at the very back of the brain, like a caboose on a train.

The outside of the brain is covered with a series of bumps and grooves. The bumps are called gyri (sing. gyrus) whereas the grooves are called sulci (sing. sulcus). This outside part of the brain is filled with tiny cell bodies of neurons, the main functional cell of the brain. Some people estimate that there are 100 billion neurons in the central nervous system (brain + spinal cord). This outer layer of the brain is called the cortex (which means “bark”). The cortex is only about 5mm thick, or about the thickness of a stack of 50 sheets of copy paper, yet it is responsible for much of the processing of information in the brain.

At room temperature the brain is the consistency of warm cream cheese. If removed from the skull and placed on a table, it would flatten and widen out a bit, like jello that is warming up. The brain is encased in a series of protective sheaths called meninges. The outermost encasing is called the dura mater (L. “tough mother”), which is thick and tough and is attached to the skull. The next layer in is softer. It is called the arachnoid layer; it adheres to the brain. Just underneath this layer is where cerebrospinal fluid (CSF) flows. This fluid is produced in holes in the middle of the brain called ventricles. CSF helps cushion the brain as well as remove waste products from the brain. Underneath this is a very thin and fine layer called the pia mater (L. “soft mother”), which adheres directly to the cortex and is difficult or impossible to remove without damaging the cortex. These three layers of meninges serve to protect the brain.

The brain can be roughly split into three functional areas, each one more “advanced” than the previous. The brainstem (and midbrain), which includes such structures as the medulla, pons, and thalamus, activates and regulates the general arousal of the cortex. Damage to the brainstem often results in coma or death. The next rough functional area is the posterior portion of the brain (parietal and occipital lobes and portions of the temporal lobes). This area is heavily involved in sensory processing – touch, vision, hearing. It sends information to other parts of the brain largely through the midbrain structures. The last functional area includes the frontal lobes. This area can regulate all other parts of the brain but is essential for goal-setting, behavior inhibition, motor movements, and language. The frontal lobes are the most advanced area of the brain and arguably the most important for human functioning – for what makes us human. In summary the three areas roughly are responsible for:

1. Overall arousal and regulation
2. Sensory input
3. Output, control, and planning

Underneath the cortex is a large area of the brain that looks white. This area is comprised of the axons of the neurons of the cortex and subcortical structures. These axons are the pathways between neurons – like superhighways connecting cities. The axons look white because the majority are covered with a fatty tissue called myelin. Myelin helps axons work more efficiently and transmit more quickly. The white matter of the brain is as important for normal brain functioning as the gray (neurons) matter is.

The brain is energy-hungry. It cannot store energy so it needs a constant supply of nutrients from blood. However, blood itself is toxic to neurons so the brain has to protect itself from the blood through what is called the blood-brain barrier. This barrier keeps blood cells out of the brain but allows molecules of nutrients (e.g., glucose) to pass into or feed the cells. The entire surface of the brain is covered with blood vessels, with many smaller vessels penetrating deep into the brain to feed the subcortical structures. Deoxygenated blood must be removed from the brain. Veins take the blood out of the brain and drain into venous sinuses, which are part of the dura matter.

The brain works as a whole to help us sense, perceive, interact with, and understand our world around us. It is beautiful in its form and function.

Image: Bi Sang by Seung Ji Baek

Let’s look forward a number of years. Bioengineering is at the point where replacing people’s organs with lab-grown ones is standard procedure. Gone are the days of transplant patients taking anti-rejection medications for the rest of their lives. Transplanted organs are all manufactured using stem cells from their own body, from bone marrow or from skin or any number of different sources. New organs are rapidly grown using modified growth hormones to speed up their development. A complete new organ is grown within a few weeks, a surgery performed, and the transplant patient home within days. Because of the relative low cost of such procedures, all have access to transplants. Replacing hearts, livers, lungs, kidneys, and other organs increased the life expectancy dramatically with most people living well over 100 years. Scientists are on the verge of transplanting the first manufactured brain. Knowledge of neural networks and cognition is at the point where a person’s entire knowledge system and all memories can be downloaded and stored as a backup. Scientists are working on manufacturing an entire replica human body as a “clone” in case a person is seriously injured. While individual organs come fairly cheap, a whole body is prohibitively expensive. A large portion of the cost is the brain. Even though scientists have created working brains, their success rate is still only about 5% (but always getting better). They go through a lot of brains.

Some people use this new biotechnology for creating backups of their bodies. Other people have started using it to enhance the performance of their existing body. In laboratory situations scientists are able to create organs that are effectually perfect. They are created in well-controlled situations and don’t have to go through the gauntlet of normal development, with exposure to teratogens, fluctuations in nutrition, and all the other things that can affect development. Popular organs to replace are hearts and lungs. People are able to run faster than ever before due to more efficient hearts and lungs. Other people get new legs or arms with well-sculpted muscles. Still other receive nanotech implants to enhance normal biological performance. None of this is being done in the United States or in the United Kingdom but there are plenty of countries that don’t outlaw the procedures

With the common body enhancing going on many people want to enhance their brains. They want a new brain created with certain gyri a little bit bigger and cortex a little bit thicker. Some researchers are working on improving the speed and efficiency of neurotransmitting. Most of the improvements in brain design come from turning on and off certain genes at different time points in development and providing the lab-grown brains optimal nutrients and stimulation. These enhancements can create brains that can learn 1000 times more in 1000 times less time.

I’ve taken a bit of liberty in my hypothetical treatment of bioengineering and biotechnology in the unspecified future. There is little, scientifically-speaking, that stands in the way of us as humans eventually reaching this point. The question is, should we? Should we seek to create immortal and essentially all-knowing humans through science. Supposing humans can build better brains and bodies, should they control and manipulate natural biological processes to the extent that they can create “superbeings”? I’m not going to answer any of the questions; I just want to raise them. With our great advances in bioengineering, technology, and neuroscience, where do we draw the line, assuming we do draw a line? Do we eradicate all developmental, genetic, and environmental diseases and disorders. Do we cure epilepsy, cancer, Autism, Alzheimer’s Disease, and ever other disorder? Do we enhance some functioning, such as hearts or muscles but not the brain?

With all advances in science, we have to always be mindful of the underlying morality and ethics of the advances. we need to make sure that our advances do not out-pace our morals.

Moral reasoning is the ability a person has to reason in and through social, ethical, and emotional situations. One component of moral reasoning is moral behavior, which is the intentional and voluntary acting in a prosocial manner (Walker, 2004). Moral behavior and reasoning are the foundation for “many human social and cultural institutions such as family structures, legal and political government systems that affect the lives of virtually every person” (Eslinger, Flaherty-Craig, & Benton, 2004, p. 100). Often situations in life are morally ambiguous and involve a choice between two actions that both have consequences that may or may not be in opposition to each other. Some researchers, such as Lawrence Kohlberg, believe that people will reason through these situations at varying levels or stages, with some in a very concrete and egotistic manner and others in an abstract and universal manner.

Lawrence Kohlberg was the first researcher to come up with a major testable theory of moral development. He formulated six stages of development, with most adults reaching stage four, a few five, and very few stage six. The first two stages are at the pre-conventional level (typically self-centered and concrete reasoning), stages three and four are at the conventional level (recognition of social norms and laws), and the last two stages at the post-conventional level (recognition of universal rights and responsibilities). While Kohlberg’s theory of moral development is a stage model, the progression through the stages is not necessarily viewed as invariant. This means that people reach them at different rates and do not always reason at a particular stage with any given dilemma. There is significant variability within and between people in moral reasoning abilities. Most research focuses on between-person variability.

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