Stroop Test

The Stroop test is a cognitive neuroscience test to demonstrate interference in the reaction time of a task. It's pretty cool and influential in experimental psychology.

Say the color of the font/ink of the words as fast as you can:
1. Red Green Orange Purple Green Blue Red Blue Purple Orange

2. Green Red Red Purple Blue Orange Blue Green Purple Orange

You'll notice the second line is significantly more difficult than the first line.

Figuring Out the Eyes

"And when I see you / I really see you upside down / But my brain knows better / It picks you up and turns you around." - Death Cab for Cutie, "A Lack of Color"

Brief Sojourn

After the exam, I attended the Hamilton Research Symposium at Mission Bay on "Life in Extreme Environments." The talks were bizarre, but interesting. They focused on microbes living in unusual places: H. pylori in the acidic stomach, bacteria in termite hindguts, and thermoacidophiles in deep sea vents. Weird stuff. People do research on this? Actually, it didn't sound too bad; researchers are forced to go to places like Costa Rica, Australia, and Japan to find termites or deep sea vents. I can't say I learned an incredible amount that's applicable to what I want to do, but at least it widened my perspective on...stuff (I guess).

The next day, I made up a preceptorship I missed when I was sick. Because of the nature of my preceptorship, I don't do too much physical exam, but I've learned that even without an exam, I can make many useful observations. "In general, the patient is an elderly woman in no apparent distress who appears her stated age and is confined to a wheelchair." And even some remarks about her appearance, speech, movements, extremities, and mental status.

I then flew home where I had a really relaxing time with family and absolutely no brain, mind, or behavior.

BMB Quiz

Last week we had a "quiz" in BMB (as Dr. Lowenstein calls it). It wasn't too bad. I like a lot of the material covered in the first two weeks. While anatomy is anatomy, it's very cool to be able to localize lesions from neurological findings. If you know where all the cranial nerves exit and how they travel, by knowing which deficits a patient has, you predict what part of their brainstem or brain was injured. We also went into some depth on spinal cord pathways, and I actually find that very interesting; light touch and vibration travel in different pathways than temperature and pain, so you can lose ability to feel light touch, but retain the ability to feel pain. I finally managed to learn about reflex arcs. The cell biology and developmental biology stuff wasn't bad. The anatomy practical in the afternoon was fairly tough; there were 70 identifications to make, and it took an hour. But it was a great relief to be done.

Home Visit

One of our assignments was to do a home visit for a patient, a very "FPC" thing to do. This would allow us to build a stronger relationship with the patient, see them in a comfortable environment, and assess their living situation for any alarming health problems. This assignment was unreasonably easy for me; my preceptorship takes place at a nursing facility, and all the patients live there. So at the end of a preceptorship, I asked a patient if she would mind me coming up to visit her apartment, and the home visit was arranged.

I did the usual things, asking her about her life, how her age and chronic illnesses affect her daily living, and her general health. I checked her medications and made sure she wasn't having any problems with them. I assessed the home for hazards like extension cords, poor lighting, lack of handlebars in the bathrooms. But obviously, as she lived in a nursing care facility, there really weren't any problems. But she enjoyed the company, the conversation, and the chance to discuss her everyday health and how it affected her.

Neuroscience Nights

This block they introduced something called neuroscience nights, which happens about once a week. It's mainly geared to those who want to learn about basic neuroscience research. We read several papers and have a discussion with an expert in the field. Last week, the neuroscience night was on channelopathies (specifically hypokalemic periodic paralysis). Channelopathies are a family of diseases caused by mutations in ion channel genes, such as myotonia, seizures, headaches, dyskinesia, episodic ataxia. This correlated well with my journal club presentation, since that, too, was a channelopathy. I think it's great that they encourage more learning about techniques of investigation, critical thinking, and basic science stuff.

(Image: Voltage gated sodium 1.4 channel, marked with mutation locations leading to channelopathies)

Journal Club II

Pain is an interesting concept for philosophers because it is an incredibly subjective experience. We all know what pain is, but it's very hard for us to describe what it feels like to someone else. We ask patients to use words like sharp, dull, burning, aching, crushing, but pain is often indescribable. Indeed, 20th century philosopher David (Kellogg) Lewis wrote a seminal philosophy of mind paper entitled "Mad Pain, Martian Pain" trying to elucidate this topic.

What interested me about the article I presented at Journal Club is that this makes some sort of objective connection to the subjective experience of pain. When someone comes in with a fever, we can test it with a thermometer. When someone comes in complaining of excruciating pain, what do we have? a lie detector test? But this paper is evidence that measurable biologic phenomena relate to the experience of pain (in fact, this concept is called nociception).

Anyway, I found presenting at Basic Sciences Journal Club to be a great experience. I learned a whole lot doing a brief literature review and studying voltage clamping. The BMB (Brain, Mind, Behavior) faculty were really supportive in helping me understand the tougher aspects of the paper. Putting together a presentation is always a learning experience, and I opted for fewer slides (only twenty-some for 45 minutes) but mostly because I had to study for an exam. I did manage one really bad pun ("at the exact moment in which you see a flow of charges down a voltage gradient, you are observing a current event"), but no one walked out so that was good. I also showed a clip of a House episode with a patient who couldn't feel pain. All in all, it was both fun and educational.

(Image: Picasso - Guernica)

Journal Club I

Last week, I presented a Nature 2006 paper at Basic Sciences Journal Club on a gene mutation which confers an inability to experience pain. It's a pretty fascinating paper, demonstrating a remarkable journey from a very rare phenotype to identifying the gene and confirming that the mutated protein is likely to cause the presentation of the disease. The paper spends some time describing these patients: they have never felt any pain on any part of their body at any time. It's pretty crazy. They have normal sense of light touch, vibration, temperature, proprioception (where their limbs are), and tickle. But the lack of pain sensation means they never learn what things are harmful to them; one of the people studied was a boy who did street theater where he stuck knives into his arms and walked on burning coals. So lack of pain is really not a gift, but a danger to these people.

They identified several families with this phenotype and mapped the disease gene through positional cloning with microsatellite markers. They finally identified SCN9A as the mutated gene in these patients. SCN9A encodes an alpha subunit of a voltage-gated sodium channel found at the ends of nociceptive (pain-sensing) neurons. Sodium channels often start action potentials, signals which communicate to the brain. It makes sense that if you had nonfunctional sodium channels at the ends of pain-sensing neurons, you wouldn't feel any pain.

The authors then confirmed this by doing in vitro studies with voltage-clamping to show that indeed, these mutations led to nonfunctional sodium channels. Although this was expected, I spent some time going over the technique and interpretation of patch-clamping and voltage-clamping. In the end, the authors had demonstrated that mutations in this sodium channel leading to nonfunctional proteins causes this very strange phenotype of insensitivity (or indifference) to pain.

(Cox, JJ et al. "An SCN9A channelopathy causes congenital inability to experience pain." Nature Vol 444, 14 December 2006, p.894-898)

MedTeach II

Our second lesson was on the respiratory system. I did a station on mechanics of breathing for one class and smoking for the second class. For these stations, we had models of lungs and a box of things found in cigarettes: nail polish remover, PVC pipe, bug spray; hopefully, this will reinforce anti-smoking messages for the students. We also had a station on lung anatomy and lung diseases like asthma. At the asthma station, we had everyone breathe out of straws and licorice to see how difficult it is to move air with increased anatomic dead space.

Our most recent lesson was on the digestive system. I ran the station on anatomy with specimens of small intestine and liver. Those were pretty good specimens, as their texture is completely different and I could have the kids try to determine whether the intestine was small or large. We also had a station on nutrition, upper GI stuff (saliva, peristalsis), and a model of the GI tract.

In any case, I really enjoyed doing this and learned a lot. I could really see some of the students trying hard to learn, fascinated by the human body. I became a better teacher as time went on, from organizational things like time management to presentation of material suitable for their level. MedTeach is a great experience.

MedTeach I

I've gotten involved in a program called MedTeach where groups of medical students teach a few lessons at local elementary schools. I really like working with Stephanie and Sarah as well as two fantastic teachers at Alamo Elementary in the Richmond district. We teach 4th and 5th graders, and they are absolutely wonderful and cute. They're enthusiastic, excited, and smart! This whole program is funded by a grant which allows us to get resources like organ specimens, posters, models, and kits.

We have taught 3 of 4 lessons so far. We structure our lessons with 4 stations for small groups of students to rotate through. Our first lesson was on the cardiovascular system with stations on anatomy, heart disease, blood cells, and pulse. It was really fun! I ran the anatomy station, and I had an actual heart for all the students to see and touch. In the pulse station, we taught the kids where to feel major pulses and to see how exercise changes pulse. We were able to get fake microscopes ("microslides") to show pictures of red blood cells and white blood cells. And we had a good station on atherosclerosis.

The kids are super receptive to the program. They really like the interactive nature. They ask good questions and some of them have a lot of background knowledge. It's really fun to work with them, and I think the teachers appreciate it too. Hopefully we can get them interested in science.