Seeing the Vultures Through the Trees

I just spent last few months trailing Turkey Vultures, looking for an elusive Black Vulture newcomer and writing about the topic (See SB Independent online Goleta Grapevine Column).

During the process, I came across several interesting references (shown below). Many websites list fascinating facts. However, in some cases I had a hard time tracking down all the primary literature that backed them.

One specific reference is to a 1964 ethyl mercaptan sensitivity study which indicates (apparently, as I didn't get my hands on the actual report) that the substance was added to gas as a means to detect leaks via the use of Turkey Vulture aggregation. However, I'm intrigued by the Smith and Paselk 1986 article whose data seems to contradict the idea that ethyl mercaptan is an attractant (or perhaps their olfactory indicator of altered heart rate is not valid) as well as the seeming lack of related reports.

Other attempts to fact find--how much a Turkey Vulture in the wild consumes in a day, for example--seemed an impossible task. In the 70's it was determined that captive Turkey Vultures eat 140 g per day. Since then much data has been collected in terms of what kind of animals are consumed but quantities apparently prove difficult to determine.

Websites
Rare Black Vulture sighting
Turkey Vulture Society
Stanfordbird Diet and Nutrition
Orange County Project to track Turkey Vultures


Primary Literature References:
Evans, B.A. and Sordahl, T.A. (2009), Factors influencing perch selection by communally roosting Turkey Vultures. Journal of Field Ornithology, 80: 364-372.

Prather, I.D., Connor, R.N., Adkisson, C.S., Unusually Large Vulture Roost in Virginia. The Wilson Bulletin, Vol 88, No. 4: 667-888.

Smith, S.A. and Paselk, R.A. (1986) Olfaction in the Turkey Vulture. The Auk, 103: 586-592.

Review Article:
DeBose, J.L and Nevitt, G.A (2008), The use of Odors at Different Spatial Scales: Comparing Birds with Fish. Journal of Chemical Ecology, 34: 867-881

Resonating References

Below are some research articles relevant to my most recent Goleta Grapevine column, A Resonating Resource which ever-so-lightly touches on neurocognition and music.

Research Articles:

Zatorre RJ. Absolute pitch: a model for understanding the influence of genes and development on neural and cognitive function. Nat Neurosci. 2003

Jul;6(7):692-5.

Cuddy LL, Balkwill LL, Peretz I, Holden RR. Musical difficulties are rare: a study of "tone deafness" among university students. Ann N Y Acad Sci. 2005

Dec;1060:311-24.

Patel AD. Language, music, syntax and the brain. Nat Neurosci. 2003

Jul;6(7):674-81.

* Forgeard M, Winner E, Norton A, Schlaug G. Practicing a musical instrument in childhood is associated with enhanced verbal ability and nonverbal reasoning.

PLoS One. 2008;3(10):e3566.

* Ross D, Choi J, Purves D. Musical intervals in speech. Proc Natl Acad Sci U S A.

2007 Jun 5;104(23):9852-7.

* Moreno S, Marques C, Santos A, Santos M, Castro SL, Besson M. Musical training influences linguistic abilities in 8-year-old children: more evidence for brain plasticity.

Cereb Cortex. 2009 Mar;19(3):712-23.

Parbery-Clark A, Skoe E, Kraus N. Musical experience limits the degradative effects of background noise on the neural processing of sound. J Neurosci. 2009

Nov 11;29(45):14100-7.

Bowling DL, Gill K, Choi JD, Prinz J, Purves D. Major and minor music compared to excited and subdued speech.

J Acoust Soc Am. 2010 Jan;127(1):491-503. 

*articles are publicly available

Lapses and Invigorations

While I have been preoccupied with employment and parenthood, Stimulating Aliquot, the chickens, garden, compost, zombie novel, sourdough starter, surfing and the like have been somewhat neglected. Fortunately, in February I began contributing to the Goleta Grapevine, a column at the Santa Barbara Independent and, as a consequence, am reinvigorating the blog. Stimulating Aliquot will still relate everyday happens to science news but now will also serve as a supplementary venue for ongoing writing projects.

Note, the URL is now http://stimulatingaliquot.blogspot.com, however, feed burner was altered concomitantly and should pick up accordingly. If it doesn't work, please send me a note. Likewise, feedback, ideas and comments are always welcome and will be addressed promptly.

The Collective

In the movie, Slither, alien zombies that look like giant pink slugs infect humans by wiggling through victim's open mouths.

I know this sounds like it has nothing to do with “real” neuroscience but bear with me here, I've been on a zombie kick.

The slug's first line of attack is through the brain, where necessary information relating to their species is disseminated, collectively linking all infectees. The zombie collective, consequently, know their celestial history, act in unison and are in love with the same woman.

After reading about mirror neurons, I can't help but reflect on how similar we are to the Slither zombies. Not that we all love the same woman, but we are, somehow, ethereally linked.

Mirror neuron cells activate when an observer sees an action or performs it. Researchers have recently shown that even observed facial expressions and hand gestures activate this mirror neuron system in humans. So, watching someones face (or hands) move, in turn activates the same brain areas that would fire if you were to make the movements yourself.

This system is likely responsible for the rubber hand illusion (how your brain can assume possession of a fake arm) that I spoke about last posting. How mirror neurons connect us with others or synthetic others (in the case of plastic arms), is likely the basis for imitation and empathy (and may have something to do with autism). And while it is characterized by action-linked responsiveness, some suggest that it may encompass or carry over into other realms such as emotion, or taste.

The cell biologist/biochemist in me wants to dissect these special cells and look at them on the single cell level. Are they at all different than cells that are not in the “mirror neuron system?” I imagine they are the same—but the activating stimuli is an idea, rather than a sensory perception. We all know that ideas can be infectious, stimulating and somehow amorphous. Perhaps the infectious nature of ideas and our brain's response to them is what makes us part of the collective.

In the zombie comedy, “Shaun of the Dead,” 'normal' people are so zombie-like, the main characters almost miss the uprising. Perhaps if we look long enough, we'll be able to dissect out all of our zombie tendencies. Until then, watch out for giant pink slugs.


There are lots of references for the mirror neuron system--this one is publicly available
Social cognitive and affective neuroscience 2007 Mar;2(1):62-66.

Halloween and the Rubber Hand Illusion

If you sit at a table with one arm on the table's surface and the other on your knee, then place a rubber arm on the table, positioning it as though it was yours, you can trick yourself into thinking the fake hand is your own. To do this, have a friend rub the rubber hand while they also rub the one balanced on your knee (using a similar stroke pattern). After a short time, you will feel as though the artificial hand is your own.

Several research papers have recently emerged regarding the rubber hand illusion. With an abundance of artificial arms (bestowed by stores tending to our holiday consumer inclinations), I couldn't pass up a zany opportunity: testing the rubber arm illusion on my friends and family. I purchased a plastic hand possessing surprisingly realistic pores, lines and even fingerprints. Given the ghoulish nature of the occasion, the arm also had a blood covered appearance. Here are some comments I heard while subjecting the good sports to the experiment:

“It doesn't feel like rubber.”

“It's like my hand moved up.”

“Mommy, can we stop now.”

“Huh, that's weird.”

As the brain combines visual and tactile experience it lets us know where our body is. For the majority of people, 15 seconds of synchronous sensation/observation—real and rubber hand together, results in the bizzare feeling that the hand on your knee moves to the surface of the table. In this state, the brain assumes possession of the artificial hand. And when scientists threaten to stab the “incorporated” fake hand with a needle, areas of the brain involved with anxiety and pain anticipation flare. Subjects report the worry levels synonymous with what they felt when the white coats came at their own hand with a sharp object. Similar experiments with no arm, but a virtual reality computer graphic, show subjects wincing with anticipation.

I can only imagine that these results are relevant to fields that include: 1) prosthetics (if I lost a limb, I'd surely want my doctors to know how to keep my brain from losing it—the limb that is), 2) psychotherapy (perhaps someone with the tendency to obsessively hand wash can come to grips with soiled hands if they utilize a therapy program involving a virtual system), 3) the video game industry (whether you're talking about how to get grandmothers to embrace Nintendo's Wii, or what the effects of video game violence are)—programmers, marketers and academicians, take note.

Now that Halloween is over, the arm resides in a box with cobwebs, spiders and a skull. Maybe next year, I'll tell you how to assume that glowing plastic cranium--the phenomenon after all, is not restricted to hands.

The Last Pop Stop: Popcorn, FAT and the brain

It started with a conversation about popcorn. My husband and the neighbor share a love for it. But my husband has another gustatory indulgence, bacon. Combined with his tendency for wild exaggeration and his knack for persuasion, my husband convinced the neighbor that uniting the two foods occurred in kitchens routinely. “I pop it in bacon grease, doesn't everyone!” was what he told her.

What exactly happens when fat hits the tongue? Rather, when it melts onto it, mixing with saliva, creeping its way into the furrows and between the taste buds. Is it the flavor, the texture or the ability of the lipid to carry smell, that tickles the mouth in such a way to warrant taking another bite and another and another?

Up until a couple of years ago, scientists would argue that our tongue likes to wallow in fat's creaminess, leaving flavor for sweet, salty, sour and savory (umami) receptors to sense. But in 2005, a protein lodged in the tips of taste cells (in mice) was found to recognize fat. The discovery suggests fat has its own flavor.

Each taste bud, containing 50 to 100 taste cells extend into tiny wispy structures, feelers, reaching into the world of the mouth. Taste receptors—proteins—are tucked into the cell like sausages baked in pastries. Slathered in saliva, they await their signal.

The protein described three years ago as the tongue's fat detector, ironically called FAT (standing for Fatty Acid Transporter) is thought to signal through nerve cells, telling the gut by way of the brain, that fat is on the way. But, the brain does more than to communicate with viscera. Neurotransmitters such as endorphins, released soon after fat intake, transmit feel good signals.

This burgeoning FAT research is lead by a group in France—a place where fat infused cuisine is emblematic. And the research team's latest results are the most mouth watering: that fat has “taste”. Monitoring the inside of mouse taste cells, the scientists noted a “taste” signature—a molecule that was released only when the cell was exposed to fat. They also established that a nerve bridging the mouth to the brain conveys this taste signal and associate a region in the brain involved in tasting. This distinction is notable. Until now, report after report states fat is flavorless. The authors conclude that “The gustatory pathway is involved in the oral perception of long chain fatty acids in the mouse.”

But what about for humans. Without evidence that the FAT protein is present in my taste cells, I have to wonder if fat has real flavor? When a mouse eats triglycerides (found in animal fat) an enzyme in saliva breaks them down into fatty acids. This process, however, has not been described in people. And it hasn't been shown that the FAT protein is in our taste buds.

Inspired by the popcorn discussion, our neighbor went home and cooked two slices of bacon. She saved the fat and later that night fortified the vegetable oil she normally uses to make popcorn. She raved about the product well before she discovered my husbands lack of candor.

I have endured many popcorn experiments. Popcorn popped in coconut oil, in corn oil, popcorn scorched in butter, popped with sugar, bathed in butter, air popped, shaken on the stove top, popped in aluminum and stainless steal poppers. Bacon grease is the last pop stop.

The experience my neighbor reported included a combination of flavor and olfactory sensations that sounded exquisitely synergistic. Now it was time to do my own experiment and I couldn't have timed it better. Last night we had a house full of vegetarians (all with a well developed sense of humor). The potluck included: baked potatoes, grated cheese, green beans, rice, pasta with red sauce, bread, bruschetta and... bacon. After dinner, we gathered in the living room to watch surfing and Tuvan throat singing documentaries and to eat, lard popped pop corn.

Going into the experiment, I was skeptical. Especially since, our popping agent was not diluted with vegetable oil. I imagined a thick film would coat my tongue and the roof of my mouth. And projected that translucent sheen eventually transferring to the inner walls of my arteries to form a thick yellow/white layer. But I have to say, the palatability was indeed superb and surprisingly light. Salty, savory—satisfying, despite my bias. Handful after handful found their way to mouths and soon it was gone.

Now, I'm sure there are a few other reasons why this popcorn was particularly delicious. After all, it contains almost every other taste stimulator. Protein remnants surely activated savory receptors. Every bite was a miniature salt explosions. And the tongue's sweet sensors couldn't be silent as saliva induces breakdown of starchy corn. Oh, the aroma too. As my neighbor put it, “It's a real delicacy. Though, sprinkling it with cheddar cheese might even make it better.”

And so the popcorn conversation spurred not only my interest in what makes fat good but what makes the perfect bowl of popcorn. I'll have to keep you posted on the science behind the flavor of fat but I will tell you an excellent popcorn recipe that doesn't require lard:

2 Tablespoons grape seed oil
2 Tablespoons butter
Heat in a stainless steal popper with a turn paddle. Add
1/3 cup popcorn

D. Gaillard, F. Laugerette, N. Darcel, A. El-Yassimi, P. Passilly-Degrace, A. Hichami, N. A. Khan, J.-P. Montmayeur, P. Besnard (2007). The gustatory pathway is involved in CD36-mediated orosensory perception of long-chain fatty acids in the mouse The FASEB Journal, 22 (5), 1458-1468 DOI: 10.1096/fj.07-8415com

MRI for the Fruit Fly

There were three bananas in the fruit basket before I left the house and when I got home there were none. “Where are the bananas,” I asked my husband. “He's a menace,” he replied motioning to the boy child. “I don't know, he was running around with them.”

I found one in my backpack that night. Four days later, I found one outside. The last one may have been eaten and at least some of the peels made it to the trash. But I did see two fruit flies on the bathroom wall. They are much smaller than house flies, not as annoying, and... not as fast. I didn't take much time to contemplate the value of the species to science and medicine before I squashed them.

The fruit fly, Drosophila, has been an incredible tool for scientists. They're cheap, fast growing, easy to mutate, and their genes are surprisingly similar to humans. Laboratories all over the nation and world are churning out lots of data on the bugs.

A new study headed by Ronald Davis at Stanford University, introduces a technique that might make future fly data even more... fruitful. Using a Magnetic Resonance Imaging (MRI) technology, the researchers imaged several life stages of Drosophila. What makes this different from standard microscopy is the organisms can stay alive.

When I first saw the report, I imaged the machine that I've seen at the hospital. A large tubular thing with a white padded table--in the middle sitting a tiny fly. The device used in the study, however, looks more like something you'd brew beer in.

The prospect of imaging the live organisms with time has far reaching implications for studies relating to many fields including development and neuroscience. In fact, the ability to “see” neurotransmitters and use complementary techniques involving genomics are intriguing avenues discussed by the authors.

Now, if only I could image my house and find the remains of our own Drosophila breeding experiment.


Null, B., Liu, C.W., Hedehus, M., Conolly, S., Davis, R.W., Zwaka, T. (2008). High-Resolution, In Vivo Magnetic Resonance Imaging of Drosophila at 18.8 Tesla. PLoS ONE, 3(7), e2817. DOI: 10.1371/journal.pone.0002817

Hand in Hand

In my recent endeavor to cut back on paper consumption, I've converted bank statements to digital versions, put a stop to mail catalogs, and have been doing most of my reading and writing online.

Speaking of, I've also been writing for www.Miller-McCune.com including their blog Today in Mice--check it if you like the kind of stuff you're reading here. But I diverge, the real issue that I'm blogging about today goes with reading/writing on the computer.

There's one bit of paper that I can't eliminate from my life; it's the writing that I do while I read science. At first I thought it was just a habit, scribbling notes and flow charts in the margins of scientific papers. But when I keep notes on the computer, without pen in hand, the information seems to trickle away like a lost train of thought.

A recent study published in the Journal of Cognitive Neuroscience suggests that it may be better to learn by writing (with your hand that is). In other words, learning and motor function go hand in hand.

Scientists from the Universite Paul Sabatier, the Universite de La Mediterranee and the Hopital de La Timone in France primarily interested in how we learn characters or symbols for written language, gave twelve subjects new characters to learn, either by handwriting or typing them. When tested, the individuals remembered the the funny lines and loop-d-loops and their orientation best when they were practiced by handwriting. Using motor skills to hit a key--even though the time spent on the task was equivalent--didn't cut it.

One intriguing aspect of the study is that the researchers used brain imaging to compare the neural pathways involved in both processes. Broca's area, historically associated with speech, is gaining recognition for a more broad role in language. The authors discern that the “left Broca's area activation seems to depend on the motor knowledge associated with the characters.”

This research is directly relevant to children learning to write. My preschool aged daughter, obsessed with the computer, sees me typing and wants to do her writing too. Letting her practice her letters with enlarged fuschia-font, I used to feel pretty good about the exercise. While the activity is not detrimental, I now make an extra effort to have her put in sufficient time with paper and pencil.

Taking the research to the level of comprehension may be speculative but the direct implications of this study and my anecdotal evidence is keeping paper in our lives.

Longcamp, M., Boucard, C., Gilhodes, J., Anton, J., Roth, M., Nazarian, B., Velay, J. (2008). Learning through Hand- or Typewriting Influences Visual Recognition of New Graphic Shapes: Behavioral and Functional Imaging Evidence. Journal of Cognitive Neuroscience, 20(5), 802-815. DOI: 10.1162/jocn.2008.20504

Filtered Science

I ask every science writer I meet the same question.

Trace science blog articles back to the primary literature and you'll notice a strikingly high proportion source from open access articles. This goes for many news headlines too. Especially freelance science writers are disabled when it comes to accessing journal articles.

When I was a university employee, it was easy to take the library -the access- for granted. The process by which scientists and their discoveries make headlines or blog lines didn't seem a mystery when I had gloved hands. Fascinating science was obvious. The experiments leaped out of the journal. Even if the science wasn't ground breaking, the topics were gripping and the experiments, telling.

But now that my gloves are off and my password not functional, titles jump from the screen, topics may seem tantalizing -but they're just titles, topics and abstracts. Getting the article, the details of the research -or the background- is another story.

My question to the science writers I meet: Access, how do you get it? The solutions I've come across are always disappointing. The best involve relying on open access articles and retrieving the articles directly from the author. Sure there are ways; but the once deft, gloved hands are now somewhat tied.

What's more disappointing than not having fingertip access to all the cutting edge research, is the realization that the public in turn doesn't either -the science to some degree is filtered.

Sea Lions Suffer

Since I frequent the same California beaches weekly, I can't help but keep tabs on the big things that wash up. The picture above is of a decaying sea lion. My friend pointed it out about a week before the photo was taken. At that point the animal was alive and exhibiting a behavior she called “the Stevie Wonder”. Swaying his head back and forth, it was clear the animal wasn't well.

These days, this isn't an unusual sight. There are many sick or decaying seals and sea lions on the beach. Many of them sway, wallow and make their way, eventually, back to “health”. The cause: domoic acid, a neurotoxic product of what's called an algal bloom. These harmful blooms are increasing and the marine mammals are suffering.

A report published in the Proceedings of The Royal Society B (February 2008) shows that domoic acid exposed sea lions are developing a chronic condition. Researchers from several agencies including California's Public Health and the National Oceans Services examined hundreds of sea lions suffering from domoic acid poisoning over the last ten years.

What they've noticed is that, aside from initial acute symptoms, the animals may develop a “chronic epileptic syndrome characterized by behavioral changes, seizures and atrophy of the hippocampal formation.” They become lazy, vomit and twitch.

The results section of the paper references specific cases of strange activities. “Abnormal behaviors included standing in atypical locations (sleeping in a public restroom, climbing onto police cars, found up to 100 miles inland in an artichoke field, car dealership or walking down the road).”

On the upside, the authors conclude that these sick animals may provide a good model for human epilepsy and also serve as a tell tale for dangerous seafood.

On the downside, as the algal booms increase, marine mammals are likely to suffer more. And if the upside is knowing when our food is bad, the obvious negative is the potential of domoic acid poisoning for you and me.

Goldstein, T., Mazet, J., Zabka, T., Langlois, G., Colegrove, K., Silver, M., Bargu, S., Van Dolah, F., Leighfield, T., Conrad, P., Barakos, J., Williams, D., Dennison, S., Haulena, M., Gulland, F. (2007). Novel symptomatology and changing epidemiology of domoic acid toxicosis in California sea lions (Zalophus californianus): an increasing risk to marine mammal health. Proceedings of the Royal Society B: Biological Sciences, 275(1632), 267-276. DOI: 10.1098/rspb.2007.1221