To wake or not to wake

To Wake or Not to Wake: Unveiling the mysteries of sleep consciousness

I was the last passenger to board a very full red-eye flight from San Diego to New York City. I scurried to my window seat, which required climbing over my already asleep neighbor. She miraculously stayed sleeping as I settled in next to her. And then, as I am inclined to do, I started wondering about her mind…

I could see her eyes move like that characteristic of REM sleep (Rapid Eye Movement). I knew that meant she was likely having a dream, but as to the content and nature of that dream? No idea. The only way I could know would be to shake her awake and ask her to immediately recall to me what was going on in her dreamworld. But, my social graces told me not to.

Fortunately for curious people like me, there are curious sleep scientists who do just that—wake people up and ask them about the moment ago when they were sleeping. One such group of scientists is working at the University of Wisconsin-Madison to develop new and improved methods for studying sleep consciousness. The team, led by Francesca Siclari and Joshua LaRocque, just released a report detailing their new method, and it’s potential for advancing sleep science.

Before explaining their new method, the authors acknowledge what’s typically been done. In a classic laboratory study, you (the subject) fall asleep for some researchers who have wired you to an EEG (electroencephalogram), which captures live readings of brain activity. An EEG can tell a trained eye which stage of sleep you are in, and so the researchers wake you up depending on what stage of sleep you are in, and how long you’ve been in that stage. At most, they might wake you up five times during the course of the night and ask you to describe the sleep experience you just left.

The Wisconsin team is doing things differently. Rather than wake you up at a few routine times throughout the night, they wake up you up randomly and often. Their hope is that this will make the data more representative of the enormous variety of conscious states during sleep. It’s not that they don’t care about what stage of sleep you are in—they care quite a bit—but they don’t want stage of sleep to be a deciding factor as to when they wake you up. So, they wake you up randomly and often, and ask a wide array of questions regarding the conscious experience you were or weren’t just having while asleep. These questions get at the content and nature of the dream: how long can you remember back into the dream; were you thinking or perceiving; was the dream mostly about you or was it more about your environment? So far, Siclari and LaRocque’s data is “in good agreement with the literature.” Meaning, a lot of previous data from sleep experimentation fits with what their new experimental method is showing.

But why are they trying so hard to understand sleep consciousness? Don't most interesting things happen while we are awake? And isn't it easier to study consciousness with an awake subject?…Sure, but great insights can emerge from studying what that something is not. So, if we’re interested in understanding the nature of conscious experience in wakefulness, we should also try to understand what happens to the conscious process in sleep. Furthermore, as we all know from having wild and crazy dreams, sleep consciousness is not devoid of interesting activity. This is partly driving Siclari and LaRocque’s work; sleep consciousness “undergoes major quantitative and qualitative changes in the course of the night.”  The asleep mind is far more complex than simply falling asleep in the evening and waking up in the morning. And the Wisconsin crew has moved us a bit closer to thoroughly investigating the complexity that ensues when we settle down to get some shut-eye.

Francesca Siclari, Joshua J. LaRocque, Bradley R. Postle and Giulio Tononi. (2013) Assessing sleep consciousness within subjects using a serial awakening paradigm. Frontiers in Psychology 4, 1-9. 

Geoengineering: Turning Problems Into Solutions

    With all the bad hype that carbon dioxide gets, people sometimes forget that its an essential part of advanced life on Earth. I'm not saying that the excess of carbon dioxide isn't a potential threat, but that doesn't mean its not manageable, or even a utilizable resource. Much in the same way technology has made possible the digestion of garbage into fuel, there may be potential for finding a way to sequester, if not benefit from, carbon dioxide emissions.

   Geoengineering is the process of manipulating the planetary environment in an attempt to counteract man-made climate change (Royal Society, 2009). This is possible in two ways, one of them being intuitive: suck up the carbon. Easy enough, but expensive. Some estimates guess carbon capturing would cost up to $1,000 per ton of carbon dioxide (House et. al, 2010). Nonetheless, the technology we have may be enough to adopt a sense of intelligent optimism about the future of climate change mitigation.

   The second kind of geoengineering has no direct effect on carbon dioxide in our atmosphere, but instead regulates global warming symptomatically. Solar Radiation Management refers to a number of "techniques" which according to the Royal Society "reflect a small percentage of the sun's light and heat back into space." This is possible in a number of ways: covering the desert with reflective material, simulating a volcanic eruption with atmospheric aerosols, or installing a satellite which reflects sunlight back into space before it even reaches the Earth. These techniques are still mostly theoretical and relatively complex, but that doesn't stop scientists from investigating what affects they could have on our planet.

    The Geoengineering Model Intercomparison Project (GeoMIP) is the product of these intrepid researchers' labor, and the findings of their project indirectly illuminate the potential for the planetary benefits of carbon dioxide. The GeoMIP climate models found that when excess carbon dioxide is paired with solar radiation management, one result is increased ecosystem productivity. 

   Forests around the world depend on carbon dioxide for photosynthesis, but excessive heat puts stress on plants, limiting their growth. Subsequently, by complementing the greenhouse effect with a planetary shade cloth, forests around the world boom in growth. Carbon dioxide could be not only be stored in trees and plants, but provide support to all the forest animal species that depend on vegetation for survival.

   Of course, a number of disclaimers should follow the relative simplicity that climate simulation offer, regarding the complexity of climate science, ecological systems, and political mechanisms of change. However, this way of looking at our so-called problems places them in a new light. Perhaps solutions to climate change can ultimately benefit, rather than exclusively put strain upon nature and society. In conclusion, keep informed, stay engaged, and look forward to the self-determined natural history of tomorrow!   

Mathematical Model Shows Evolution Shifts Invaders into Higher Gear

The invasions of species may not be breaking news on television the way an invading army is, but the problem has jumped to priority number one in the last few decades for those concerned with protecting our natural spaces and resources. Invasive species are posed to displace native plant and animal communities as their ranks move ever forward. But how fast does the takeover happen? And is it always happening at the same speed?

A study conducted by T. Alex Perkins at the University of California, Davis and published in the February 2012 issue of The American Naturalist set out to tackle these questions. In the paper, he outlined a mathematical model that could be used to predict the rate at which an invasive predatory species could invade the range of its native prey. Perkins took it a step further than the models other scientists have created: he accounted for the gradual evolution of the invading species. Perkins is applying a theory of invasion that recognizes that invasion is a strategy for an organism in and of itself, not just something that happens. Invasive species are adapting to a new way of life, one that demands that they overtake new territory quickly and fully.

Rewarding these invasion tactics brings the possibility of rapid evolution in some invading species. Perkins' model shows that if species are ever so slightly evolving as they multiply and spread across the landscape, they are adapting to take over new habitats faster and faster. This idea of an accelerating invasion goes counter to many of our intuitive ideas about evolution and invasion: namely, that an invasion is going to happen much faster than evolution, making evolution irrelevant to many invasive species concerns.

This change is not evenly spread though. Once all the numbers were plugged in, Perkins noticed an interesting trend in the projected locations of the population. After the first accelerating front of the invasion, subsequent waves were much more constant in their rate of spread and evolution. This is because adaptations for invading were more strongly selected for at the front lines of an invasion where improvements to speed and physique were greatly rewarded and dissonance in the ranks quickly squashed out.  

Perkins’ mathematical model helps us to demonstrate a few simple truths that were previously hard to quantify, though it is somewhat limited. The mathematical relationships built into it assumes that we know a lot about the mechanisms of invasion and this sort of rapid evolution, when we really still have many questions. Still, it shifts our paradigm from considering evolution as just a slow, lumbering force to one that also has a more targeted, fast acting component.

Scientists are increasingly finding the world is not static. Evolution can act faster than we ever expected, and plays a key role in invasions around the globe. Moving closer to the facts and nuances of ecological invasions puts us closer to winning the fight against them. Many questions remain to be investigated on all fronts.

Caffeine Versus Adenosine, the Perks for Your Brain on Caffeine

In our brains we wage a war against the molecule adenosin, a neuro transmitter, that it tries to pull us into a stupor; luckily caffeine is here to intervene. Everyday, an army of adenosine molecules assaults our neurons and causes our brains to slow. But caffeine mediates the siege and steps in-between us and adenosine.  Two groups, one out of the U.S. Institute of Health led by Stephen Simons and one out of the University of South Carolina led by Mark Davis are chronicling the battle of the interactions between adenosine and caffeine inside us all.

The battleground of your brain is made up of cells called neurons. Their unique shape allows them to form networks in which chemical signals pass from neuron to neuron across small gaps. Throughout the day, adenosine floods your neurons, sticking to special receptors, causing the neurons to struggle to begin the chemical cascade that allows the neuron to pass signals. The more adenosine on a neuron, the more sluggish your neurons are and the more tired and fatigued you become.  Caffeine comes to the rescue, perking you up by sneakily sitting in-between these receptors, blocking their access. In fact, caffeine blocks adenosine receptors so well, that it makes your neurons fire faster. On a macro level, caffeine driven increases in neuron firing lead to interesting consequences for learning, memory, and exercise.

Let us say for instance, that you’ve had a two of cups of coffee before a long night of activity. The Simons team found, that amount of caffeine you ingested is enough to markedly increase neuron firing in the hippocampal region of your brain--this area is most heavily associated with learning and memory. The increase actually promotes the formation of connections between nuerons and may improve memory and increase rates of learning. Or let’s say that you decided to run on a treadmill. The Davis team found, that if you normally became tired after ten minutes, with the same amount of coffee, you could run for a maximum of five additional minutes--an increase of up to 50%. Now I am not suggesting that you chug a bunch of energy drinks, but to stave off fatigue while writing a paper or in the gym, you could enjoy a cup of Joe.

To Delve Even Deeper:

Check out this Wiki article on long term potentiation in neurons! 

Sources:

Papers:

Stephen B. Simmons, "Caffeine-induced Synaptic Potentiation in Hippocampal CA2 Neurons," Nature NeuroScience 15 (2009): 23-25.

Mark J. Davis, "Central Nervous System Effects of Caffeine and Adenosine on Fatigue," American Journal of Physiology, Regulatory, Integrative, Comparative physiology 284 (2002): R399-R404.

Extra Help/Background Info:

Selena Coppock, editor., Biology Review (New York, Random House, Inc, 2010), 229-264.

No More Cousteau: How the Caribbean Lionfish Invasion is Decimating the Reef

Picture a coral reef. What do you see? Schools of brightly colored fish, long branches of corals and sponges swaying in the tide, maybe a diver, and endless expanses of the most beautiful blue. Now picture all of that gone. The only thing you see is rock, large bushes of overgrown macroalgae, and lionfish.

Lionfish, a species of fish native to the Indo-Pacific reefs, are now firmly established in the Atlantic and Caribbean. They have invaded this part of the world in the last 25 years. It is thought that they were first introduced in Florida form an aquarium destroyed in a hurricane. In the Cayman Islands specifically is being very negatively impacted by the invasion. The lionfish threaten the two major industries: fishing and SCUBA tourism. You see, lionfish are predatory fish. They can eat up to 4% of their body weight in juvenile fish and crustaceans daily. Without any natural predators, the lionfish’s eating habits have become a threat to the local biodiversity. They eat mostly grazer fish young, which would grow up to play a vial part in the health of the reef. The grazers eat the macroalgae that can stop the corals from getting enough sunlight they need to grow. (Corals are animals, but they live in a delicate symbiotic relationship with microscopic algae that live inside of them. If the algae don’t get enough sunlight, the coral and algae both die.) Coral is a basis of many fish on the reef; lose the coral, you lose the fish. Lose the fish, lose the coral. Lose the coral, lose the beauty of the reef. Without the beauty of the coral and fish, the Cayman Islands lose the appeal for divers  (Diving in the Caribbean is a US$2.1 billion per year industry.) Also, lose the grazers and you lose the large predatory fish that are caught and eaten by the people of the Caribbean. (Projections based the current rate of decline in reef fish life due to lionfish predict fishery yields to decrease by 30-45% by 2015.)

Frazer et al. were interested in looking at how a mass removal project would effect the reef and lionfish populations. They organized a team of volunteers to dive in three locations around Little Cayman and kill the lionfish. They measured the amount of time spent under the surface with the number of lionfish eradicated, and found that targeted removals were effective and time efficient.  With the lionfish that were killed and brought to the surface Frazer and his team of physiologists were able to get information on the types of food the lionfish ate at different developmental stages, which can help scientists better understand the exact their impact on the reefs and reef life. When Frazer and his team returned 6 months later, they also found that the lionfish were not returning to the vacated habitats. Frazer deemed the removal project a success.

I believe that the lionfish invasion can be controlled by spreading the word. In 5 years, it is said that there will only be lionfish on the reefs of the Caymans. Small removals are constantly happening with the local dive masters. Lionfish is also finding its way onto menus all over the Caribbean. By creating an understanding of the importance of the removal of the fish and creating a demand for the consumption of it, the reefs can be saved.

For the full article: http://www.tandfonline.com/doi/full/10.1080/10641262.2012.700655#.UjdxRHDPXao

Subsurface Habitable Zones

The circumstellar habitable zone is a band of space in a solar system that is neither too far away nor too close to the sun for liquid water to exist on a planet's surface. The traditional habitable zone is relatively small; most planets in the universe will fall somewhere outside of their star's habitable zone. A factor that is not usually considered is that life can exist without liquid water on the surface level of a planet. It is possible for life to take it's energy from a planet's core rather than from the planet's star, and liquid water can more readily exist closer to that geothermal energy.

Sean McMahon, Jack O’Malley-James, and John Parnell have published a paper in which they calculate the range of a subsurface habitable zone (SSHZ) – a counterpart to the original habitable zone that becomes larger and larger the farther below a planet's surface you are willing to look for life. Life has been found on Earth living as far below our surface as 4 kilometers, and the SSHZ for an earth like planet at depths that extreme is over three times as wide as a habitable zone where you're only looking for life on a planet's surface.

McMahon, O'Malley-James and Parnell's calculations are exciting because based on this information it isn't unreasonable to believe that far more planets are capable of sustaining life in some form than we originally believed. One of the significant downsides to this however, is that the further below the planetary surface that you go, the harder it is for us to effectively test for the presence of life. So even though there is a much larger range in every solar system where we believe life could exist, actually verifying the existence of that life becomes more difficult accordingly.

Sources:
Sean McMahon, "Circumstellar Habitable Zones for Deep Terrestrial Biospheres"

As Global CO2 Levels Increase, So Does CO2 Exchange in Northern Hemisphere

   Every year across the northern hemisphere of the globe, the seasonal cycle of the earth causes the planet to breathe. CO2 is released in the winter and absorbed in the spring as new plant growth uses the atmospheric CO2 for photosynthesis. A new study lead by Heather Graven at the Scripps Institution of Oceanography UC San Diego suggests that this breathing pattern is becoming significantly more dramatic.

   Many are aware that the amount of CO2 in the atmosphere is steadily increasing every year. Graven’s findings show that the amount of CO2 being absorbed during the summer months and released during winter months has increased throughout the northern hemisphere as well.

   The team collected data from two ground sites: One in Mauna Loa, Hawaii and the other in Barrow, Alaska. Data was also collected from aircraft observations conducted during from NOAA’s Carbon Cycle Group Aircraft Program and HIAPER Pole-to-Pole observations from 2009 to 2011. The team then compared these data to CO2 levels observed in 1958 to 1961 at the same ground sites, as well as aircraft observations collected during an international scientific study known as the International Geophysical Year.  

   Their results were somewhat shocking, with an increase of 32 to 59% seasonal CO2 exchange when the data from 1958 to 1961 were compared to data from 2009 to 2011.  Identifying the specific cause has proven to be difficult. The team compared several complex simulations that use historical data to account for various ecosystem processes, but did not find any clear trend. It is clear however that this increase will not slow down in future years. Furthermore, it is a definitive indicator of large-scale, widespread ecological change that has occurred over the past 50 years, especially throughout boreal forests. Graven’s team calls this a “major shift in the global carbon cycle”, and suggest that this may cause people to “under-predict future changes.” It is very possible that in the next fifty years, the earth's respiration patterns will increase at an even faster rate. The study was published in the journal Science on August 30^th and can be found online.

Source:

Graven, H. D., R. F. Keeling, and S. C. Piper. "Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960." Science Magazine. N.p., 08 Aug. 2013. Web. 15 Sept. 2013. http://www.sciencemag.org/content/341/6150/1085.short