Biology 202

            The circadian rhythm’s independent internal activity is observable when mismatched with separate incoming patterns of activity input from the environment. Circadian rhythm is the body’s internal twenty-four hour clock that regulates biological processes such as wakefulness, metabolic rate, and body temperature. The internal clock is fundamental to a living organism’s daily activity. (1)  Seasonal changes can cause the environmental inputs to be interpreted as different from the circadian rhythms. A person’s daily behavior can modify to the surrounding environment. As a result, the I-function is stimulated by a difference and the person becomes uncomfortably aware of the environmental change.  The body’s circadian rhythms neurological signals go unnoticed until a change creates inputs different from those of the internal body clock.

When the Bryn Mawr yoga instructor begins her session by uniting the voices of the class with the universal sound of ohm, scattered chuckles roll across the floor. Bowing to the light within, centering oneself and falling into the unconditional embrace of yoga is not a fundamental aspect of western lives. The mental facet of yoga falls under the mental training umbrella of meditation. Meditation is a practice that attempts to calm and focus the mind on one subject, releasing all other thoughts. Oftentimes this focus is geared inwards, towards the self. Meditation is gaining respect in western civilizations because a plethora of studies are showing it provides predictable, reproducible and measurable medical benefits. However, meditation is not ingrained in our culture; it is not a lifestyle like it is for monks under the Buddhist religion. Buddhist monks who dedicate their lives to meditation exhibit unbounded mental potential for mind-body control. From the far off peaks of the Himalayans to the Bryn Mawr yoga classroom, meditation is occurring and our minds and bodies are absorbing its side effects, which currently science can’t fully explain. How meditation affects the brain and alters our physiological states is a simple question without a simple answer.

In recent years, our society has been inundated with rapid technological developments particularly when it comes to computers.  Sociologists have noted the impact that the increase in computer use could have (and to some degree already has had) on our society as they begin to replace human contact (4).  Between 1996 and 1999 alone, the number of homes with internet access doubled (1).  On a neurological level, this is concerning because increased computer use may develop habits that strengthen certain areas of the brain and as a result do not allow others to strengthen to their full potential.  This is especially concerning when it comes to children because their brains continue to develop through adolescence.  In 1999, children were spending an average of 24 minutes more with the computer per day than just one year before (1).  How will this technology that previous generations have not been raised with impact the neurological development of children?  This paper is an exploration of the habits that computer use reinforces and the impact this has on the development of attention and chemical responses to emotions in the brain. 

I had originally intended to write about postpartum depression, which had afflicted my grandmother, a mother of ten children, one of whom died at an early age, during the 1950's and 1960's, as well as my aunt, who suffered from it during the late 1970's; however, while researching this topic, I discovered another, and far rarer disorder that debilitates new mothers, entitled postpartum psychosis. While postpartum depression affects one in ten new mothers, postpartum psychosis only affects one in five hundred to one thousand new mothers during the first few months after childbirth (1). What interested me the most was the striking difference between the two disorders; at first observation, postpartum psychosis appears to simply be a more intense version of postpartum depression, but upon a closer look, it becomes clear that it is its own unique disorder, with its own unique problems and solutions.

Language is the way we as humans interact with the world.  We use it to communicate with each other about the present, to speculate about the future, and to write down our past so it will not be forgotten.  No other species is able to do this.  Language is truly what separates us from the rest of the animal kingdom.  But how did this incredible ability evolve, and why is it not observed in other creatures?  There are many theories about the development of language, but I believe that it is the chance product of a complex and tireless brain constantly searching for connections.

The theory currently held by most scientists is that of neo-Darwinism.  This is the belief that language evolved by natural selection, just as any other trait.  Though no other animal possesses true language as humans do, research has revealed that chimpanzees and bonobos, our closest relatives, share certain neural characteristics with humans related to language (1).  In humans, two areas in the left hemisphere are very involved in the production of speech: Broca’s area and Wernicke’s area.  Both these areas are larger than the corresponding areas of the right hemisphere.  Though these areas do not control language in chimps and bonobos, the corresponding areas are larger in the left hemisphere than in the right, suggesting that a common ancestor had a brain with this asymmetry.  Many scientists take this to mean that this common ancestor’s brain developed language as it evolved into the modern human brain.  Chimps and bonobos still have these asymmetrical areas, but they never evolved into Broca’s area and Wernicke’s area as they did in humans.

We all eat to survive. We need calories, and nutrition, and for our cells to bed fed in order to function. Beyond that, though, lies a realm of questions. As humans, we have an interesting relationship with food. We crave certain foods, and are sometimes told that we’re craving just what we actually need- that if our body is craving orange juice, it may be because it’s lacking in vitamin C. However, quite often, we crave foods with little nutritional value (1). What is our body telling us then? Can we distinguish between something we greatly enjoy the taste of, versus something the cells in our body need in order to grow and replicate? With these cravings, has food- sugar in particular, become an addiction to us, like drugs? Researchers are finding foods with sucrose- the white, crystalline sugar, may have an addictive quality, perhaps explaining why we so often crave the foods containing this that we know aren’t very nutritionally beneficial to us.

If you were asked to pick something that you thought would trigger an undiscovered artistic talent, you probably wouldn’t reply, “degenerative brain disease”, but it’s completely plausible. In one such case, Tommy Mchugh was brought to a hospital, in 2001, because of a sudden onset of severe headache. Testing showed that he suffered from subarachniod hemorrhages caused by a stroke. After surgery he complained of what can be described as a “split mind disorder”, where his perceptions and personality were altered (3)(6). He began to compulsively express these altered perceptions through art, which he had shown no interest or ability in, prior to the stroke.  

Studies of these cases are suggestive of mild frontotemporal dysfunction. Specifically, Tommy’s tests of executive function showed impairment, mainly in tasks which required alternating between categories or tasks, but not to the extent found in previous studies of frontotemporal dementia. Clinical characteristics include; “…a profound alteration in character and social conduct, occurring in the context of relative preservation of instrumental functions of perception, spatial skills, praxis and memory”(7). Patients also experience a decline in social conduct, “breaches of interpersonal etiquette, tactlessness and disinhibition” as well as “impairment in regulation of personal conduct”(7). They also experience speech impairment and cognitive changes (7)

            The nervous system has so many different tasks to do every day that it is a wonder that there are not more mishaps in the day-to-day function of humans.  Despite the fact that overall, our nervous systems allow us to make it through everyday without falling over or running into things, there are cases where somewhere wires get crossed and the usual predicted outcomes do not occur.  One of the easiest examples to observe is anything to do with sensory input, because so many different things in our environment go into a single experience every instant of our lives.  There are people with synesthesia who associate smells, tastes, or colors with certain words, or other kinds of sensory recombinations.  Another interesting example is that of how pain is experienced and interpreted by the nervous system.  As I thought about this function of the nervous system in relation to other senses, the phrase “blinding pain” entered my thoughts and would not go away.  I began a search of this phrase that does not really make sense upon further thought but is used so frequently in common discourse.

It is a rather frightening and rather unnerving thought that psychosurgical procedures can be traced back to Neolithic times, roughly 40,000 years ago (2, 6, 7).  Current psychosurgical techniques are by no way in a state of perfection so one can only imagine how crude and often fatal these ancient procedures were.  Modern psychosurgery can better be understood through a more recent historical investigation of the era of neuroscientific inquiries that was going on during the 19th century (2). 

The first indications of skull surgery come from the archeological unearthing of skulls with holes carbon dating back to 1500 BC (2).  Further study of the bone surrounding the hole, evidence of proper healing, and estimation of the individual’s lifespan indicate that the hole was in fact surgical in nature rather than some sort of head wound.  This ancient method is called trepanning and was more than likely used in order to release demons and evil spirits that were thought to be trapped in the skull and were linked with madness and brain disease.  In many cases the reasons for trepanning were completely bogus and purely based on religious and spiritual beliefs and therefore showed no benefit. However, in other sincere medical cases such as strong headaches, brain tumors, intracranial pressure due to hematomas, hydrocephalus, etc., this procedure potentially had some therapeutic effect and is actually a technique that is still being used to this day to relieve intracranial pressure.   This procedure was performed without any sort of anesthetic and took about 30 to 60 minutes to cut through the skull.  If the tool used to make the hole in the skull does not touch the brain itself, the patient had a relatively high chance of survival. 

My high school history teacher claimed that his wife was only able to conceive their daughter after seeing a hypnotist. Doctors deemed her infertile after years of trying everything from fertility drugs to acupuncture. I was always skeptical about his claim, until my cousin ended her thirteen-year-long, pack-a-day smoking habit cold turkey through hypnosis. I began to wonder if it is really possible to convince our brains and nervous systems to yield to our desires simply by focusing our attention and obeying the suggestions of a hypnotist.