Final work for the year

With a week to go before finals I thought it was a good idea to summarize our remaining work for the semester.  You should do the following before our final exam on December 9th:

• Leave one comment or make one edit to each of the two other disease wiki pages that you were not involved with.  This is two comments or edits total.
• Read either chapter 4 or 5 of Michael Gazzaniga's The Ethical Brain on enhancing the brain through training and pharmaceuticals.  Read both if you find it interesting.  You can expect a question about this reading on the final exam.

Light Triggers a New Code for Brain Cells

I found an interesting blog post at Neuroscience Blog that explored the idea that light could in fact trigger a new code for brain cells. The article explores the idea that brain cells can adopt a new chemical code in response to cues from external stimuli, including light.  This was tested using tadpoles at the University of California.  Tadpoles were tested because of there change in pigmentation in order to protect themselves from predators.  They become almost translucent from their ability to release a type of dopamine hormone that leaves the pigments tightly packed. Scientist found that bright light alters this pattern in tadpoles. Because they are already hooked up to the hormone-producing target, illumination can result in noticeably paler tadpoles in as little as ten minutes. Co-author Nicolas Spitzer stated that the new dopamine neurons are not simply activated at random. These signal-switching cells receive a signal directly from the eye and are part of a brain circuit.  These brain circuits are not unique to tadpoles and are seen in a variety of animals such as humans. These cells help monitor light levels, particularly for coordinating daily rhythms of behavior.

Before scientists believed that only activity turned the switch in order to specify which transmitters a neuron could use. This experiment/discovery allows for the possibility that the stimulation of specific circuits to low levels of neural chemicals that underlie some human ailments that could selectively alter brain chemistry. The light could help those people who experience seasonal affective disorder, and their symptoms including depression, which descend during long winter nights, lift in summer and also abate when they are regularly exposed to bright light, a therapy that can be as effective as anti-depressant drugs.

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Is Anybody In There?

There are various diseases in which a patient has a form of brain death or damage. Recently, as most of you have probably heard, there was a man "mis-diagnosed" after a car accident. Originally the doctors diagnosed him for PVS which is persistent vegetative state. For 23 years this man sat, or should I say lay, in a coma. After some advanced neuro-imaging looking at brain function based on blood flow and metabolism, the doctor re-evaluated his diagnosis. The man's function was found to be almost intact and he was able to type to communicate. He began recounting all of the years he was in the hospital, he could hear everything everyone was saying but he could not communicate back. The diagnosis has changed to Locked-In Syndrome

Steven Novellablogs about his suspicions regarding the strangeness of this situation. He explains that PVS entails insufficient brain activity in which the patient may move their eyes but they really cannot communicate with their surrounding environment. Novella also comments that people are diagnosed with PVS unquestionably. MCS is minimally conscious state in which the patient still cannot communicate however they have slightly higher brain function. Another but very rare diagnosis is Locked-In Syndrome in which the patient is paralyzed but are conscious so they still cannot communicate with their surrounding environment. Novella's suspicion is in the fact that it is very rare for a person to be mistakenly diagnosed with PVS when they are really locked in because they differ greatly in degree of brain function.

Novella has several other questions regarding the case, please feel free to read more!

My Spidy Sense is Tingling!

It is known that most animals have early warning systems to help them avoid bad situations. Whether it is finding shelter before the rain or sensing danger before it attacks they can avoid these bad situations. The article "Brain Study Points to 'Sixth Sense' " addresses if humans can use this same ability to avoid danger.
The study started with reports that primitive aboriginal tribesmen headed for higher ground days before the Asian Tsunami. It was Washington University in St. Louis that started the main studies of an early warning system. "Our brains are better at picking up subtle warning signs than we previously thought," said Joshua Brown, Ph.D., a research associate in psychology in Arts & Sciences and co-author of a study on these findings in the Feb. 18 issue of the journal Science.
At the top of the frontal lobe along the wall of the longitudinal fissure is the anterior cingulate cortex (ACC). The ACC activates when one is making hard decisions or has made a mistake. Studies have shown this area also activates when one is about to make a mistake and can help avoid that mistake. Due to past experiences the ACC may be able to warn the brain that a negitive outcome may result from its next action, but also can warn that danger is impeding and to avoid the situation entirely.

Attack of the Phantom Limbs!

Rest assured phantom limbs do not pose any threat. Instead the blog I read titled, “Phantom limbs can contort into impossible configurations”, posted in October 2009 on the Neurophilosophy blog, http://scienceblogs.com/neurophilosophy/, addressed a study focusing on motor control over phantom limbs in humans. The phenomenon of phantom limbs occurs in a select number of amputee patients. Following the removal of a limb, some individuals still feel the presence of their limb as if it were attached. Scientists believe the brain’s body image remains the same following the surgery. The majority of cases are unable to manipulate their phantom limb. Recently a paper was published in the journal Proceedings of the National Academy of Sciences, in which seven individuals, all of whom experienced such sensations following an amputation of an arm, were subjected to therapy, in order to improve control over their “limb”. Initially those participating in the study found it difficult to move their limb however with enough therapy; the patients were capable of controlling their limb. To achieve this ability, the researchers relied on visual imagery; each individual was asked to mimic a movement depicted by a visual cue. Once the individuals had control over their limb; the researchers next challenged the participants to perform movements which would defy normal anatomical boundaries. This too posed to be a challenge however; over time the patients were able to effectively achieve such a range of movement. Interestingly, the study revealed one case where a “phantom wrist joint” was perceived by the individual which allowed person to perform these normally impossible movements. The blog concludes although the brain’s body image is genetically based, it may be updated through sensory feedback. I found this post to be extremely interesting, although I had heard of phantom limbs; I was previously unaware of such current research.

LSD's Effects on Blind Subjects

I found an interesting blog post on the http://www.mindhacks.com/ blog which summarizes a 1964 study in which the effects of a semisyntheic psychedelic drug on completely blind people. The study article titled "Effects of a hallucinogenic agent in totally blind subjects" was published in the Archives of Opthalmology. In this study, 24 totally blind test subjects were given LSD to see if they could experience visual hallucinations.

LSD, or Lysergic acid diethylamide, is a non-addictive, non-toxic , schedule III drug that is well known for producing vivid psychedelic hallucinations characterized by radiant colors and patterns behind the eyes. Humans with normal functioning retina's often observe these effects when exposed to LSD. The retina is the light sensitive tissue that lines the inner surface of the eye which contains photo-receptive rods and cones that detect lightness and darkness as well as color. The 1964 study aimed to see if the retina played a role in hallucinations.

The double-blind study conducted in 1964 investigated LSD's effects on 24 completely blind test subjects. It was noted that 14 of the test subjects reported visual alterations after receiving the LSD. Twelve subjects reported simple visual stimulation, two noted complex visual alteration. Seven test subjects reported colored visual experience and seven had non-colored visual stimulus. The study concluded that a functioning retina is not required to produce visual hallucinations. It is interesting to note that the visual alterations only occurred in subjects who had had prior visual sensation. Subjects that had gone blind much earlier in life (two years old or younger) did not perceive any visual hallucination effects.

Paper: http://www.lycaeum.org/research/researchpdfs/1094.pdf

Coffee and Sleep

In the Neuroscience Research Blog I came across an interesting post regarding a study that looked at how coffee effects sleep. The blog post Neuroscience Research on Coffee and Night Workers, links readers to an article in Neuroscience News, Study Finds Coffee and Nighttime Jobs Don't Mix. I found this article to be of interest particularly because I work night shifts as an EMT during the school year and often find myself consuming a caffeinated beverage or two while I'm at the station. I had always thought that caffeine was losing its effect on me because I would be able to get back from a late night 911 call and still be able to fall asleep even thought I had consumed around 100mg of caffeine a few hours before. However after reading this study I will be paying closer attention to the amount of caffeine I consume thorough the day.

According to research that has been publisher in the journal Sleep Medicine. Caffeine is the most widely used stimulant to fight sleepiness. However most people are unaware of its negative effects on sleep, especially to those who work nights. The study also reports that this negative effect on sleep only increases with time and age. The study on sleep was conducted with twenty four men and women. These participants were divided into two groups: a 20-30 age group and a 45-60 age group. The participants were all gathered in an experiment room and for two days were deprived of sleep. Three hours before the participants were allowed to sleep they were ether given a 200 mg caffeine pill or they were given a placebo.

All participants that were given the caffeine pill showed "decreases sleep efficiency, sleep duration, slow-wave sleep (SWS) and REM sleep." This occurred in both age groups however middle age people are more susceptible to these adverse effects on sleep. Authors of this study suggest that the research has high implications for those people who do work at night and use caffeine to deal with fatigue or even jet lag. They also recommend that everyone over forty reduce their coffee consumption especially if they work at night.

Neurobiology Blog Post

I recently read the blog entitled “The Reading Brain” by Jonah Leher. This blog was written as a literary review of the book with the same title written by Stanislas Dehaene. The entire point of this blog was to show that the brain was not hardwired for reading capabilities, but as humans we have modified reading and writing to fit the functions of our brain. This is an interesting idea, because as a species we have taken a portion of the brain that would typically be used in object recognition and devoted it to a completely new purpose, to identify and associate meanings to letters. The blog starts off describing Dehaene’s idea of the “letterbox “area of the brain, a small portion located right behind the left ear that is used solely for reading and word recognition.

The letterbox area of the brain associates sounds to the letters that make up our words. After this deciphering process is completed the message is then sent to other portions of the brain that tag on a meaning behind the words. This process can be divided into two pathways, one is a quick route that we use when we read words that we already recognize and know the meanings behind. This would be day to day type reading not much extra thought goes into it. The second pathway is when we encounter an unfamiliar word, this takes much more time because we have to decipher the sound of the word first and then figure out its meaning afterwards. Dehaene goes on to explain that even the shapes of our letters have been dictated by our perceptual capabilities, which are due to the limitations of the retina that are universal in humans. “The moral is that our cultural forms reflect the biological form of the brain; the details of language are largely a biological accident.”
http://scienceblogs.com/cortex/2009/11/the_reading_brain_1.php

Brain Size and the Science of Zombies

In the past, it has been generally accepted that organisms (including humans) with physically smaller brains are inferior in mental performance. Researchers also linked this trend with the fact that people do not use all of their potential brainpower and that percentages of brain usage vary in a standard bell shaped curve. Well, all of this information has been proven quite wrong through several different studies. This blog post highlights one research paper published by M. Henneberg in 1998. The blogger chose this paper for its concise and clear overview of the research. The post touches on several points that throw this old belief out the window. These include the fact that other species, not just hominids, have shown increases in brain size throughout history and that our ancestors actually showed a small decrease in brain size. The paper referenced in the blog tells that brain size is proportional to body size, not mental capacity. The Greg Laden's blog post can be viewed here.

Another blog I found stimulated two of the biggest parts of my personality: my love of science and biology and my geekiness. This blog post highlighted the research of Dr. Steven C. Schlozman. His area of expertise? Zombie neurobiology. Dr. Schlozman satisfied his sci-fi/horror side by looking at the characteristics of zombies in classic films such as Night of the Living Dead and determining what areas of the undead brain cause these behaviors to occur. He highlights the frontal lobe, ventromedial hypothalamus, cerebellum, and basal ganglia. I found this blog to be quite humorous and quite clever for the simple fact that Dr. Schlozman applied real neurobiology research to something as silly as zombies. The zombie neurobiology blog post can be viewed here.

Neurobiology post

            Post-traumatic stress syndrome is a mental illness generally common in those individuals who have suffered from events that are threatening to life or bodily integrity. Most recently there has been a marked increase in the amount of cases of this illness in soldiers returning from battle. However, individuals suffering from physical and sexual assault can also endure this syndrome. Although the diagnosis of this syndrome is still  a debatable topic, the symptoms are more fully characterized.  Some common symptoms include re-experiencing the event in varying sensory forms, avoiding reminders associated with the trauma, and chronic hyperarousal in the autonomic nervous system (ANS). The syndrome is diagnosed generally after a patient suffers from the afore mentioned syndromes for more than a month and often times result in job loss or social changes.

            As previously mentioned, it is hypothesized that the development of this syndrome is related to the ANS in close relation to the limbic system which functions in regulating expression of emotions and instinctive defenses associated with fight or flight. This system also plays a crucial role in memory. The ANS on the other hand acts to regulate smooth muscles and other viscera in either a stimulatory or inhibitory manner. When the limbic system responds to sense of threat, hormones are released that can activate the sympathetic division of the autonomic nervous system.  This system of stimulation in turn results in the individual acting as if they were in the danger they experienced initially that induced the trauma in a fight or flight type of response. Individuals may also experience complete numbing of oneself to the outside world as away to escape the remembering of the trauma experienced.

             Some of the current options for treatment include psychopharmacology, psychotherapeutic intervention such as through psychoeducation and case management.  More on the treatment option can be seen in the specific treatment section and the principles of treatment selection section.

Disease wiki update

I have made comments on all of your wikis.  The original deadline for the completed wiki was Monday, November 23rd, but with the delay in restoring the wiki server, let's move that deadline to November 30th.  During the last week of class you will be peer reviewing each other's pages.  So please respond to my comments and make revisions to your pages by November 30th.

There is one other thing I would like you to do with the text from your wikis.  Copy and paste all text into a word document and upload to Turnitin by November 30th.  When you go to this website and log in (or start an account if you have never used it before), you will need to know this information to upload your text:

• Class ID: 2990727 
• Password: diseases

Who wants pond scum proteins in their neurons?

It may be you one day, if you are unfortunate to have trauma to your brain, spinal cord or peripheral nerves.  The new field of optogenetics is taking light sensing proteins from the green alga Chlamydomonas and expressing them in the vertebrate nervous system.  Read about how this technology is being used to control neurons in the brain, and to restore normal breathing in mice with nerve damage.

By Wednesday, November 25, I would like each of you to find a research story related to neurobiology that interests you, and post a story about it on this blog.  Provide a paragraph or two that gives the basics of the research findings, and hyperlinks to related content on the web.  This would be similar to the paragraph above, but I would like you to provide a bit more information than I have.

Literature search assignment

This past week we read an influential paper on the effects of lactic acid and K+ ions on muscle fatigue. But this paper was published back in 2001. For this coming Monday I would like you to use the literature database ISI Web of Knowledge to look up what has been published on the topic since 2001.

You could use ISI to search terms like lactic acid, potassium and muscle fatigue to search the recent literature. But another great method is to look at any publications that cite the Nielsen paper that we read. This type of search is not possible in Pubmed, but can be done with ISI.

So, go to ISI Web of Knowledge and search for the title of the Nielsen paper to find its reference. It will look like this:

Notice where it states "Times Cited". According to this ISI reference, this paper has been cited by 88 other papers. That is a pretty high number and suggests that this paper has had a strong influence on the literature. Other researchers are reading it and citing it in their papers.

Click on the number 88 to see a list of these citing references, and look through them to find articles that seem relevant to the question of whether lactic acid causes or prevents muscle fatigue.

For Monday, prepare a typed page with the following:

• Give the references for three papers that are relevant to this question.
• Give a summary of the current state of the literature. According to the references you find, what is the effect of lactic acid on muscle fatigue?

Lastly, click on the citation map for the Nielsen et al. 2001 paper. This is a neat graphic representation of how all of these papers are tied together in citation strings.