Saturday, March 4, 2017

Screen Time Blues

In the previous post a brief explanation of melatonin and cortisol was given to help give an explanation to the origin of our sleep cycles. In this post I am not going to give a lecture on when you (and your family) should and shouldn't view computer/TV/smartphone screens for optimal health. This post a a brief explanation simply of what screens do to the brain, notably in the later evening. Hopefully you can derive what is best for you and your family as far as time to view screens from these few brief points regarding screens and the brain:



  • Blue light is really the worst part of the spectrum when it comes to inhibition of the release of melatonin, which is the hormone that assists you to fall asleep. Research done by two different groups in 2001 found not only that blue light was the greatest inhibitor of the release of melatonin, but also found that blue light from LED sources (the source of light on all electronic devices now) is the blue light causing the greatest problems with the release of melatonin.
  • There are a few answers that have come to attempt to allow one to use screens while being able to prepare one for bed. iOS 9 was the first smartphone system to introduce a preset time of day at which the screen would shift you a very yellowish source of light--Night Shift. Prior to this the original investors of Picasa created a program called f.lux in which you can have your computer screen set to do the same idea--remove the blues and violets by changing any whites to a beige/yellow. This program can still be downloaded and used on Macs and PC's. 
  • Another approach (that is far more simple) just involves the reduction of the brightness of a screen. A reduction in brightness ultimately results in a reduction of blue-light photons reaching the photoreceptors that communicate with the melanopsin-containing ganglion cells which then inhibit the release of melatonin.
  • In this interesting interview with a pair of researching professors in the field, they simply state that screen time in the hour prior to going to sleep results in:
    • Taking longer to fall asleep.
    • Less amount of REM; this results in less time dreaming
    • A greater degree of sleepiness after an 8-hour sleep
    • Greater difficulty waking up after an 8-hour sleep
  • Just as white light (which has a greater concentration of the blue wavelengths resulting in it being white vs. the classic yellow colour of an incandescent filament) can be seen as having a negative affect upon those who can live and work with a consistent schedule. On the bright side, those who have rotating shift work, or those who frequently travel great distance via plane in which they quickly want to alter their circadian clocks can use the blue light from such devices to alter their circadian rhythm at a faster pace.  
  • While a myriad of different papers have been written regarding the decrease in the average amount of sleep by teenagers since the introduction of the smartphone, the key point to all of them is that smartphones have reduced the amount of sleep by teenagers (on average). This reduction is sleep will result in slower formation of the prefrontal cortex, and lesser amount of content being kept in the long term by passing through the hippocampus. The key point is that while the numbers and controls in that various papers may be different, all agree that there is no benefit to our sleep with exposure to screens, notably in that last hour before we plan to go to sleep. 

Thursday, February 23, 2017

The brain's alarm clock and lullaby song - cortisol and melatonin.

How did you wake up this morning? It is a Thursday to me, and fortunately I have my five year-old (biological alarm clock) who still wakes up very reliably between 6:20-6:45 every morning. He has a very stabilized circadian rhythm, or circadian clock. Had he not awoken me, my alarm was set to go for 7:00. Would I have waken up at 7:00 without an alarm? So how does our sleep cycle work with the help of two hormones, and what can we do to get a good balance between those two hormones, cortisol and melatonin? I hope to look into a number of questions regarding sleep and our brain, and discuss two key hormones in this post. Let's start by looking at a typical daily graph of these two hormones:



As we can see in the graph above, when comparing the two hormones, melatonin appears to rise and fall at a sharp rate, whereas cortisol seems to escalate and then drop off more gradually. This can be seen very easily in individuals who have a very rhythmic pattern of sleeping. Not to pick on him, but my son rarely steps outside of the 19:30 - 20:00 window to fall asleep, and as a result, has 6:20-6:45 very consistently as a time to wake up. He likely has a very consistent graph that would look something like that above. Unfortunately, as we leave childhood, many of us, for a myriad of reasons, seem to allow our circadian rhythm to become far less predictable and consistent.

There are many ways by which we (notably starting as teens, and continuing into adulthood) can modify these levels which can ultimately result in less efficient means of sleeping:

  • Screen light (notably the blue light) suppresses the release of melatonin. Therefore, if given the the choice of reading off something digital vs. something printed (or emulates being printed and requires a backlight--Kindle, etc.) you are far better to go with the latter to ensure release of melatonin. 
  • Consolidation of memories is something that is key to retaining memories. Note the time in the graph above from about 11 pm to 3 am where the melatonin is very high--this is needed for us to allow the hippocampus to move our memories into our long-term memory. If you have seen the movie Inside Out, this is the stage where all memories are moved out of the main control centre into the storage area; that is a perfect analogy. (If you haven't seen Inside Out, and you have any remove interest in neurology, you need to watch it--it is brilliant.)
  • The circadian rhythm in teenagers is typically atypical; it does not look like the textbook example above at all. Teenagers are authentically feeling groggy and able to stay up late as things that are currently high in their blood, such as the growth hormone, can affect both cortisol and melatonin. 
  • In this earlier post I discussed some negative effects seen in children who watch excessive amounts of TV. When we break this down into really watching television programming vs. playing video games, video games can result in a much greater alteration to these hormone levels. Not only does the screen light suppress melatonin, but the action of playing a video game can release large amounts of cortisol. Research has shown that between all categories of video games, first-person shooters ultimately release the greatest amount of cortisol. Ultimately, regardless of the genre of the video game, playing video games late at night is reversing the direction both of those hormones are wanting to go to assist one in falling asleep.
  • Our high level of cortisol in the morning can be seen as being quite helpful for the handling of anxiety and stress. Cortisol ultimately promotes the use of all parts of our brain, while fatigue (low cortisol) can often have us stepping away from using areas of our brain key to decision-making such as the PFC. People deciding to stay up late may not be able to have it as high the next morning; this results in one unable to handle the same level of stress and anxiety as one who had a good night's rest.
  • Wanting to move towards really having a consistent circadian rhythm? Make your schedule for weeknights very concrete. While life can often be complicated, if you can ultimately make the amount of screen-time in the evening limited, and place physical exercise as a consistent part of your daily routine, you will likely find your circadian rhythm becoming more like the textbook example above.
  • Drink coffee or tea in the morning to wake up? The chemical caffeine isn't what really raises your alertness, the caffeine releases mycotoxins, which ultimately lead to the release of cortisol, which then wakes us up. 
  • Drink wine or beer in the evening to go to sleep? Alcohol leads to drowsiness as a result of an increase in production of melatonin. Any significant amount of alcohol can result in higher-than-normal levels of melatonin in the morning, resulting in a groggy feeling the following day.
  • In many countries, (including my home, Canada,) melatonin is available in any pharmacy as an over-the-counter drug, while cortisol requires a prescription. Cortisol is restricted as a prescription drug likely as it shuts down the adrenal glands upon being consumed in any noticeable amount.
Please contact me if you have any key points about either cortisol or melatonin that you think should be added to the list of points above, and if you haven't already watched it, I hope you can take some time to watch this show!


*Note: The diagram used at the top was taken from this blog posting that has ten pieces of advice regarding healthy sleep patterns.

Tuesday, February 21, 2017

Neurotransmitters and parts of a vehicle -- Part II

In the previous post, a brief summary of three key neurotransmitters, dopamine, epinephrine and norepinephrine were discussed. The analogy to parts of a car were a small (and to me, risky) step outside the realm of science into any form of metaphoric creativity. In this post we will have a quick look at three other neurotransmitters, some of their key roles, some of the disorders associated with them, and of course, the parts of a vehicle that they could be. Those three neurotransmitters are acetylcholine, histamine, and serotonin.



Acetylcholine

  • Acetylcholine, or ACh, is the most critical neurotransmitter directly associated with learning and memory. It is the only neurotransmitter that plays a role in what is called synaptic plasticity: the ability to change the electrical strength of of synaptic charge.
  • Consistant changes to electrical strength to a familiar neural pathway ultimately results in focus. Students who suffer from ADHD may have a lack of ACh playing a role in such a lack of focus.
  • ACh is made in the nerve cells, and requires choline. Choline is a chemical we take in via what we eat, it is primarily found in eggs, proteins, and dairy. 
  • ACh receptors on the surface of all skeletal muscles react to ACh by causing a contraction of the muscle. Oddly enough, the opposite it true of the cardiac muscles that make up the heart--ACh causes them to relax.
  • Students who struggle with focus and memory may have a shortage in ACh. Increased amount of sleep, and a healthy diet are two means by which this level can be increased.
  • In modern vehicles, electricity plays such a critical role in operating so many components of a vehicle. While the nerves are the electrical wiring, the electricity (electrons) are the ACh chemicals. (Notably if you have one of those dashcams remembering all of your  driving for you.)
Histamine
  • Histamine, contrary to what all people with allergies may believe, is a critical neurotransmitter that does more than cause allergies. Many antihistamine drugs are now built to act upon histamines outside of the brain and surrounding CSF membrane, as that is where their allergy exists, and the antihistamines in the brain can be problematic because.... 
  • Histamine acts upon areas of the brain to release cortisol. Cortisol causes alertness and anxiety, and is ultimately what keeps us awake. As a result, antihistamines significantly reduce our cortisol levels in our body resulting in drowsiness. A lack of histamines results in a lack of alertness.
  • Histamine-levels in individuals with schizophrenia are much higher than average; as a result those with schizophrenia can often have a comorbidity with insomnia. 
  • There is currently research being done that is beginning to prove that a possible delay in the progression of multiple sclerosis in an individual can be avoided with in increase of histamine levels.
  • Histamine could be compared to a vehicle's stereo: perhaps not as critical as some other components, but certainly keeps the driver awake and engaged in their driving, instead of allowing the mind to wonder. Also, stereos play a critical role in our lives in areas outside of the vehicle (brain).
Serotonin
  • Serotonin is chemically formed by a reaction with tryptophan, which is a chemical that we find in foods that can make us drowsy. 
  • Roughly 90% of all serotonin in your body is in the small and large intestine.
  • Though it is a neurotransmitter, serotonin is also found in the plant and fungi kingdoms.
  • Serotonin plays a critical role upon such factors as our mood, happiness, appetite, aptitude, and ability to prepare for sleep.
  • Basically all antidepressants, to one extent or another, cause a reduction in which serotonin is metabolized (broken down), and thereby cause an increase in the concentration of serotonin to the brain. 
  • Our serotonin used for neural purposes is produced in the pineal gland, named after the fact it is said to represent the shape of a pine cone.
  • Hallucinogens and psychedelic drugs are chemicals that contain serotonin attached to another chemical; their metabolism in the brain results in the sensations felt by the person.
  • Serotonin is the heater of the vehicle. Its level can go above average (high temperature) without seeing any long-term negative effects--you can roll down a window. If its level is too low, a lack of serotonin can result in many difficulties associated with mood, happiness, and positive behaviour as a whole. 

Sunday, February 19, 2017

Neurotransmitters and components of a vehicle.

As a high school teacher, I find one of the most difficult concepts to truly have students comprehend is that of how electricity works, and what each electrical unit describes. One analogy that usually helps is one that relates electricity to water. The diagram below is one I frequently like to use:




When presenting on the brain, it becomes difficult to go into too much depth without bringing the basic neurotransmitters into the picture. Being much like electricity, neurotransmitters operate at such a minute level that we never really get to see how they work first hand. An analogy that works well (and is perhaps quasi-plagiarism from David Macaulay and his diagram above) is how I like to compare the neurotransmitters to components of a vehicle:

1. Dopamine

  • This neurotransmitter is one of the most basic yet necessary transmitters. It is responsible for making decisions, motivation, reinforcement, as well as rewards. This is like the engine of the vehicle. It can be used to reward ourselves, and there are many critical decisions we need to make based on how well we know the engine.
  • Addictions to certain levels of dopamine can lead to various addictions. If you become accustomed to driving while revving the engine between shifting gears, you may continue to do it for years to come. People who become accustomed to the high level of dopamine achieved through such acts as gambling and drug use at a young age (< 25 years old) can become addicted to that mode of keeping high dopamine levels for years to come. Much of this corresponds to dopamine predominantly having a significant role in the prefrontal cortex (PFC).
  • The body will naturally raise dopamine levels through feelings of accomplishments and reaching goals. For this reason, having students/children set goals allows them to reach goals and release dopamine as a result.
  • Many drugs used to treat ADHD do so through their primary function being that to increase the  level of dopamine in the brain. With higher levels of dopamine, those with ADHD report being far more able to take time to reflect (an executive function in the PFC) and are less likely to make spontaneous decisions.
2. Epinephrine
  • Epinephrine is used interchangeably with its other name, adrenalin. This name is derived from the fact that epinephrine is primarily produced in the adrenal glands.
  • Exercise causes a slight increase in the concentration of epinephrine in the body.
  • While epinephrine can influence the emotional state in a number of ways, the emotion most strongly correlated to epinephrine is the negative state of fear. 
  • Increase in the level of epinephrine can lead to an increased ability with memory and consolidation of information.
  • Epinephrine can be like the brakes of the vehicle. Brakes can be hovered over when there is fear, and some of our clearest memories can be experiences in which we were slamming on the brakes.
3. Norepinephrine
  • The main focus of norepinephrine upon most organs is to prepare the organs for a higher degree of operation, and a greater rate of energy consumption.
  • Norepinephrine is key in cardiovascular activity as it increases heart rate and glucose consumption by skeletal muscles. 
  • Over 90% of the body's norepinephrine is produced in a part of the brain stem, the pons.
  • Many anti-depressants work to increase the concentration of norepinephrine by decreasing the rate at which the body degrades the norepinephrine into other chemicals.
  • This is the fuel pump of the engine; without it we would have a lack of fuel reaching the engine. 
Beginning to understand those three neurotransmitters is a key first step in understanding both how a healthy brain operates, but also what can be the origin for many disorders. Sometime in the near future I will give a brief explanation of one more neurotransmitter, serotonin, and two hormones that from many perspectives can be seen working much like neurotransmitters: melatonin and cortisol. 

Tuesday, February 14, 2017

Valentine's Day: testosterone, estrogen, vasopressin, and oxytocin.

We often talk about testosterone in males, and perhaps not quite as often, estrogen in females. This is a great episode of Quirks and Quarks in which Bob MacDonald interviews a researcher who has looked at the effects upon the brain, (and resulting sexual behaviours,) of both women and men with low vs. high testosterone levels, and the difference in the perceived attractiveness of females who have high vs. low estrogen levels.

Relating to the previous post, he discusses how we have evolved out of high-dependence upon our olfactory lobe, but that female brains "light up" the more the odour of their partner is a contrast to their natural order, and this is an attraction that promotes genetic diversity.

Near the end (15:00), there is discussion of how our brain is able to become chemically dependant upon sex based on the the chemicals it releases, and the importance of oxytocin and vasopressin in relationships.  Could we have genetic variance that results in some people being more genetically suited for monogamy?

Enough said--take a listen and post any thoughts on the interviews on this episode (from 1:40 - 22:40):

https://beta.prx.org/stories/33552


Saturday, February 11, 2017

Olfacoception - a brief overview. (or, "How does smell work, neurologically?")

In the field of neurology, smell is such an interesting anomaly. To adults, having smell does clearly serve purposes--allow us to smell food, alerts us that something may be burning, or tells us that we need to change a diaper. So why does smell start out as one of the (if not the single) most important senses that we then allow to regress?  The answer to that is simple--the degree to which we depend on it. While at birth we are relying upon smell to find milk, by the time our eyes have learned to focus, we find it much more easy to visually identify milk instead of smelling for it. (Not to mention that the smell may be somewhat sealed when in a bottle.)

The olfactory lobe (or olfactory bulb), the area of the brain where we process smell, and is a small area on the underside of the frontal lobe. The olfactory receptor cells line the upper side of the nasal cavity and then transmit to the olfactory lobe via the olfactory nerve. Enough with the technicalities; here are some of the areas of research in this realm of the brain you may find interesting:


  • Research done in the 1920's created a generalization that we can detect about 10 000 different odours. This was challenged in 2014 by research in France in which a team led by Caroline Bushdid found that 90% of humans can detect roughly 1 trillion different odours.
  • Unlike many neurons, olfactory neurons can regenerate. This ability by the olfactory nerves is one reason they are currently being researched so extensively, so that one day that ability could be applied to other types of neurons and nerve cells.
  • Roughly 3% of our human genome code is commited to olfactory receptors, neurons, and the lobe (bulb). This high percentage of our DNA not only shows links to our genetic ancestry, when we were likely far more dependent upon smell, but also to its incredible complexity.
  • Smell and memory can often have a strong correlation. The olfactory lobe is right beside the hippocampus (responsible for storing memories) and not far from the amygdala. For this reason, specific smells that strongly relate to specific memories can also be strong triggers for emotions. 
  • Olfactory hallucinations can play a part in many neurological disorders. People with epilepsy, tumours, with a history of strokes or experiencing a stroke all may experience hallucinations in which they claim to be smelling something while the olfactory receptors are not chemically receiving that smell (the smell is not physically existing). 
  • Olfactory hallucinations and olfactory illusions are two different forms of neurodeception. Hallucinations are when the receptors are actually not receiving any chemical reaction, but the olfactory lobe is acting as though the olfactory nerve is telling it the chemical is present. Illusions are when the receptors have a chemical reaction, but misinterpret it as a different smell. Research in 2001 looked at how easily we can fall for illusions with similar odours.  
Where can this come into play in the classroom, that is a bit of a difficult question. In a class where there odour usually takes a very small role, maybe it could begin to be experimented with. An example I will use is that of the degree to which the various components in grade 11 biology where they are learning about cellular respiration and then photosynthesis, all at a cellular/molecular level. Is there a chance that you could be burning one candle while teaching cellular respiration and then a candle with a very different odour when teaching photosynthesis? This is something I may put to the test this year.

To hear interviews with Dr. Keller, the lead researcher in the study that theorized we smell over 1 trillion different odours, click on this link:

qq-2014-03-29_02.mp3

Sunday, February 5, 2017

Research regarding excessive television viewing and the brain.

If you go back a "couple" years, you may remember reading this poem:


While I can't remember which of the Shel Silverstein books it comes from, when I recently finished reading about new research in the field of neurology and television viewing, it was one of the first things I thought of. How far from the truth was Silverstein? New research is beginning to state that as we watch more and more TV, the more one can argue we become one. This research suggests that excessive TV watching results in:

  • Anatomical differences in both grey and white brain cells
  • Lowers the verbal abilities
  • Higher rates of antisocial behaviour
  • Higher rates of obesity
  • There is a positive correlation between average number of hours and number of mental health disorders
It is key to note that this research by Hikaru Takeuchi at the University of Japan does come with some benefits to those who watch excessive amounts:
  • Greater development in the visual cortex
  • Increased thickness in the hypothalamus
While the researchers used children aged 5-18 and placed them in interval categories of watching from 0-4+ hours of TV, they did find that with those benefits, came lack of development in areas involving intellect.

Another study, collaboratively by the University of Nebraska Omaha and Florida State University found that when they undertook similar research upon about 3 000 pairs of siblings, that genetics significantly shapes the brain, and as a result behaviour towards likelihood to watch TV. They concluded that genetics accounts for about half of the predisposition towards being addicted to watching TV.

If this second article begins to question the degree to which genetics related to the development of the brain create a natural predisposition to watch more or less TV, it is still struggling to say that TV has no net negative effect. When looking at the first article, there were five key negative points to watching TV extensively, and two key positive ones. This brings us to the hypothesis that I think most have come to accept: while TV in moderation may not have negative effects upon the brain, there are so many activities (e.g. music-based, sport-based, creativity-based) that allow for positive growth in the brain while TV viewing allows the brain to enter a dormant state that results in minimal growth.