Clive Wearing is a 70 year old British man who contracted herpes simplex encephalitis in 1985. The virus destroyed his hippocampi bilaterally (as well as surrounding areas). He has complete anterograde amnesia and can only remember up to about 20 seconds. He retained the ability to play the piano and conduct a choir (which he did previously to his illness); this is because this procedural memory involves different areas of the brain, including the basal ganglia and the cerebellum. I’ll revisit this case over the coming days. Meanwhile, here is a clip from a BBC production that presents part of Clive’s story.
Hippocampus Anatomy Video
To follow up my previous post on the hippocampus, here’s a video posted by drbobrd on YouTube. He uses a model of a brain to explain some brain anatomy, including the hippocampus and fornix.
The Hippocampus in 400 Words
Within the temporal lobe of the brain is an elongated structure called the hippocampus. Some people have compared its shape to that of a seahorse (the word hippocampus comes from the Greek {hippos + campos}, which roughly means “seahorse”). This structure is special for a number of reasons. One is its role in memory encoding and consolidation.
From cytoarchitectonic standpoint, the hippocampus is special because unlike the surrounding cortex, it consists of only three layers instead of six. The hippocampus is phylogenetically an old part of the cortex, which means that it is an older branch on the evolutionary tree, whereas the rest of the cortex (more accurately called the neocortex), especially cortex of the frontal lobes, is a much newer development.
The hippocampus resides within the medial portion of the temporal lobe. It is continuous with the parahippocampal cortex, entorhinal cortex (the hippocampus receives its main input from this cortex), and perirhinal cortex.
The hippocampus sends white matter tracts off its dorsal and posterior portions (the hippocampus also communicates through other tracts and pathways – this circuit is not the only output of the hippocampus). These white matter tracts are the fimbria of the hippocampus (technically, the fimbria are the “offshoots” of the alveus of the hippocampus). The fimbria proceeds upwards from the posterior portion of the hippocampus, at which point it ceases to be the fimbria and is called the fornix.
The fornices (plural of fornix) are prominent white matter tracts passing above the thalamus and medially in the brain. The fibers travel forward, then turn downward just posterior to the anterior commissure (a white matter tract that connects both hemispheres) to terminate in the mammillary bodies, two bumps on the ventral side of the brain. They are part of the hypothalamus of the brain. From there, the pathway courses upward through the mammilothalamic tract (MTT) to the anterior nucleus of the thalamus. From there axons course to the cingulate gyrus, then to the underlying cingulum (large white matter tract), and back to the hippocampus (via the parahippocampal and entorhinal cortices). This circuit is part of the limbic system and is called the Papez circuit. This circuit is important for emotion and memory.
Positive Effects of Bupropion
I recently interacted with a person who is depressed (I’ve had a lot of exposure to people with depression over the years but I want to write about one in particular). This person was a pleasant person but a bit dysthymic in general; this person came across as somewhat down and depressed. Recently he started taking bupropion (Wellbutrin) for depression. It’s made a world of difference. Now he appears euthymic and quite animated – it’s a good change. I know that anti-depressant medications are not effective for everyone (and I am fairly critical of psychotropic medications in general and don’t think any should be taken lightly) but in this case, the improvement was marked. It was like night and day. Wellbutrin, incidentally, is also an effective medication for helping people stop smoking (trademark name of Zyban). I have no affiliation with GlaxoSmithKline, who makes the drug (it’s also available as a generic), I just recently witnessed its effectiveness.
Alien Limb Syndrome
Video site for watching surgeries
I’m quite fascinated by human anatomy, especially neuroanatomy. The human body is amazing; it’s something of a miracle that it develops and works as well and as often as it does. The brain is very complex with up to 100 million neurons (that’s also an estimate of the number of stars in our galaxy) and 100 trillion synapses (connections between neurons)! 100 trillion is an estimate of how many individual cells the entire human body has. We have as many synapses as cells in the entire body. The brain is complex and beautiful. It has symmetry but individuality.
I discovered a website that allows you to watch some surgeries live (or to view archives of past surgeries). OR-Live.com is informational and free. For those interested in neurosurgeries – everything from scoliosis surgery to tumor resection to deep brain stimulation – here is the direct link. Most of the videos are available in Flash format for web-viewing. Many are also available to download as a video podcast. Warning – please don’t watch the videos if you get queasy easily; if you feel queasy while watching one, take a break and do something else for a while.
I hope my readers enjoy this site as much as I have in the past and will continue to in the future.
Banjo Pickin’ Brain Surgery
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.
Mental Health Parity – Finally!
Here’s the American Psychological Association press release about the recently passed mental health parity law in the U.S. This is great news for insured people suffering from mental health disorders as well as for psychologists who will now be able to receive better reimbursement for services provided. Here’s a NYTimes article on the bill.
WASHINGTON—President Bush signed mental health parity into law today, taking a great step forward in the decade-plus fight to end insurance discrimination against those seeking treatment for mental health and substance use disorders. This historic legislation requires that health insurance equally cover both mental and physical health.
Congress passed the legislation as part of a new bill that also includes tax extenders, changes to FDIC and the controversial financial rescue plan. The House passed the legislation today by a vote of 263-171. On October 1, the measure passed the Senate by a vote of 74-25.
“With passage of this bill, insurance companies can no longer arbitrarily limit the number of hospital days or outpatient treatment sessions, or assign higher copayments or deductibles for those in need of psychological services,” said Dr. Katherine Nordal, the American Psychological Association’s (APA) executive director for professional practice.
For over a decade, the APA has worked with Congress to achieve a full mental health parity law ending discrimination in health insurance coverage against those suffering from mental health disorders.
The 2008 bill closes several of the loopholes left by the 1996 Mental Health Parity Act and extends equal coverage to all aspects of health insurance plans. It preserves existing state parity and consumer protection laws while extending protection of mental health services to 82 million Americans not protected by state laws. The bill also ensures mental health coverage for both in-network and out-of-network services.
According to the National Institute of Mental Health, more than 57 million Americans suffer from a mental health disorder. According to a 2008 nationwide survey by Harris Interactive in conjunction with the APA, 25 percent of Americans do not have adequate access to mental health services and 44 percent either do not have mental health coverage or are not sure if they do.
Additionally, a 2006 survey from the Substance Abuse and Mental Health Agency reports that 49 percent of U.S. adults with both serious psychological distress and a substance use disorder go without treatment.
“Research shows that physical health is directly connected to emotional health and millions of Americans know that suffering from a mental health disorder can be as frightening and debilitating as any major physical health disorder,” said Dr. Nordal. “It’s our hope that passage of this bill will force our health care system to finally start treating the whole person, both mind and body.”
The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world’s largest association of psychologists. APA’s membership includes more than 148,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.
Decomposing Statistics
Statistics are used by all but understood by few. In fact, studies have shown that 94% of people have little to no understanding of statistical methods. OK, that last statistic was made up; I wrote it to make a point though. I could post something like that on this blog and people would believe it and possibly even repeat it. The sad thing is that it probably isn’t that far from reality. In social science and neuroscience research we use statistics to understand data and support hypotheses. This post will serve as a statistical primer. I will not discuss how to calculate statistics, rather I will write about the underlying assumptions and theory of statistics. I will also discuss how to properly use and understand them (and hopefully avoid misusing them). I hope to help you become a more informed consumer of statistics.
When did we start using statistics and why?
Joel Best wrote a brief history of the use of statistics in his excellent book Damned Lies and Statistics: Untangling Numbers From the Media, Politicians, and Activists. [I urge everyone to read the book to be more informed about statistics. All quotes will be from the book. It provides only a superficial treatment of actual statistical methods – which he states is the case – but it provides a good theoretical background for being a critical thinker about statistics]. He states that statistics rose in popularity as governments and social activists wanted ways to track and “influence debates over social issues” (p.11). Early statistics were used almost exclusively for political purposes, especially to shape social and governmental policies. From the beginning, statistics were used for non-neutral purposes. They gave credibility to arguments.
One assumption that people erroneously make is that statistics are neutral and that they represent truth. They are useful for aggregating a lot of data but the problem is that most statistical methods are based on certain assumptions about the underlying data (e.g., that it is normally-distributed). However, many times researchers use certain statistical methods and make conclusions based on those data when the methods are not appropriate for the data. Even simple descriptive statistics (e.g., averages) can lead to people making erroneous conclusions.
People who create statistics all have a purpose for them. Researchers are all biased and have agendas. It just may be to get their research published or it might be for other ulterior reasons. Social activists use statistics to create social problems (see p. 14); they are not the cause of the “problem” but they try to raise awareness of it by turning it into a “problem” that we need to pay attention to and solve. This can often be a good thing but activists are using statistics to give credibility to their cause (e.g., “According to the World Health Organization, between 12 percent and 25 percent of women around the world have experienced sexual violence at some time in their lives.” source). Governments also use statistics to defend their position (e.g., “Crime rates decreased by XX% from last year. See! we are doing our job.”) and sometimes to counter the claims of activists.
The media pick up on statistics, on activists, because they present a new story and might even be controversial and controversy sells. Businesses also use statistics to promote their causes. Not everyone or entity will collect data in the same way either – one police station might have different criteria for counting an assault than another one has.
The author Best proposes three general questions to ask when seeing a statistic used.
- Who created this statistic?
- Why was this statistic created?
- How was this statistic created? (pp. 27-28).
Many times people don’t even know enough to ask those questions or to research the answers to those questions. After all, as Best points out, we are largely an innumerate society (this holds true world-wide). Innumeracy is the math equivalency of illiteracy. A majority of people are uncomfortable with even basic mathematics and completely oblivious to statistics. After all, mathematics is abstract and requires a lot of mental effort to use and understand. It is often not taught as well as it can and only reluctantly learned in school. Once out of school, people rarely need to use more than basic math and so they forget what they learned. The other problem that we have is that we accept math (and by extension, statistics) to be perfect and infallible (Gödel demonstrated in effect that this is not the case). Best describes this fallacy:
“We sometimes talk about statistics as though they are facts that simply exist, like rocks, completely independent of people, and that people gather statistics much as rock collectors pick up stones. That is wrong. All statistics are created through people’s actions: people have to decide what to count and how to count it, people have to do the counting and the other calculations, and people have to interpret the resulting statistics, to decide what the numbers mean. All statistics are social products, the results of people’s efforts” (p.27; emphasis added).
So what do you do when you view a news program on TV or read an article or hear an activist or politician quote a statistic? If it makes you go, “Wow!” then that is one sign you need to step back and really scrutinize it (which you should do even if it doesn’t surprise/scare/etc. you). If you agree with the point the show, article, or person is trying to make then you really need to step back and critique the statistic. This means you need to understand your biases. It is easy to only want to confirm our hypotheses and beliefs and ignore anything that might contradict them. This is generally adaptive to help us process a lot of information but it can be a problem when we don’t critically view statistics, especially when they are “bad statistics” (which you can never discover without critiquing them). When you view or read a statistic, that is the time to ask yourself those 3 questions Best proposed and go from there. You might discover something interesting.
I’ll post more on this subject later.
Reference
Best, J. (2001). Damned Lies and Statistics: Untangling Numbers From the Media, Politicians, and Activists. University of California Press, Berkeley and Los Angeles, CA.