Everybody Must Get Stoned?

This is a startling result and I have to wonder why it isn't being more widely publicised:

In the present study, we observed smaller brain weights and volumes in male macaque monkeys after 1.5–2.3 years of exposure to marijuana at plasma drug levels comparable to those in treated humans. Exposure to marijuana was associated with a similar reduction in mean fresh brain weight, as well as mean fresh weight and volume of the left cerebrum, compared to matched, placebo-exposed animals. For both drugs, the magnitude of these effects was in the range of 8–11%. The reduction seemed to be global (ie including all brain regions), but was most robust in the frontal and parietal lobes. In addition, both gray and white matter volumes appeared to be reduced to a similar degree.

Typing Away Our Memories?

...
"I think [technology] might hurt the type of memorization that we usually think about, like remembering the name of an actress, but I think there might be some benefits, too," said study author Betsy Sparrow, an assistant professor in the department of psychology at Columbia University in New York City. ...


Yes, that is true. Remember that fairy tale that human memory is infinite? I used to laugh at that because it was obvious to me that my memory was anything but infinite. So in my early 20's I set about learning as much as I could about memory and devised a simple memorisation system that must have been effective because many people comment on the strength of my memory. My typical response is anyone can have a good memory they just need to know the tricks. That isn't really true. I was fortunate in that I inherited a good memory ability and then built on that. Nonetheless all of us need to think about the implications of relying *too much* on modern technology as an information storage utility.

Can we all Possess Savant Like Skills?

My friend in New York sent me a link addressing the work of Alan Snyder who for many years has been arguing that within all of us reside hidden talents that can be unmasked through inhibiting certain regions of the brain. He goes so far as to state that this ability can constitute genius, more on that latter.  While I have a number of problems with the various assumptions embedded in the ideas of Snyder and his team I also acknowledge that most laypeople operate from the same assumptions and as do many professionals. Nonetheless the perspective of Snyder may have utility and so in the spirit of "News ideas are like seedlings, easily trampled", let's play the game and see what we can learn ...

Eat Smart, Be Smart

They like to say that we cannot improve our intelligence. Recent studies have contradicted this as has my personal experience. There are a great many things we can do to improve our intelligence but to achieve maximum benefit requires careful management and a holistic approach to health. By "holistic" I do not mean that New Age crap or the continual popping of pills, but rather an integrated approach where we address many aspects of our lives. This includes:

• Being happy. If you are lacking happiness then this is the first challenge you must address.
• Sound sleep. There used to be the boast of how little sleep one could get by on. Great, welcome to future dementia.
• Aerobic fitness. Absolutely essential.
• Don't just exercise your brain, push it. Make it work. Read material that you find challenging, that makes you think, that challenges your preconceptions. One of my favourite quotes is:*Gelett Burgess: "If in the last few years you haven't discarded a major opinion or acquired a new one, check your pulse. You may be dead."
• Remember that exercising the brain is not just about conceptual work, bodily exercises that require co-ordination and timing can also be very important. This is further highlighted by recent research indicating that simple physical training in co-ordination appears to be beneficial for some children with ADHD. This appears to be related to the cerebellum(little brain). This part of the CNS has been neglected for too long.
  
• Eat well.

This study from the FASEB journal involved the administration of some supplements to gerbils. It was found that these readily available compounds enhanced their cognition. The nutshell goes like this:

DHA: an important omega 3 fat that is a substrate for NPD1, a neuroprotective compound that prevents apoptosis(programmed cell death).
Choline: an important component in cell walls and also a substrate for acetylcholine, the "memory neurotransmitter".

A news item on the study can be read here.

FASEB, July 2008

Dietary uridine enhances the improvement in learning and memory produced by administering DHA to gerbils

Abstract:

This study examined the effects on cognitive behaviors of giving normal adult gerbils three compounds, normally in the circulation, which interact to increase brain phosphatides, synaptic proteins, dendritic spines, and neurotransmitter release. Animals received supplemental uridine (as its monophosphate, UMP; 0.5%) and choline (0.1%) via the diet, and docosahexaenoic acid (DHA; 300 mg/kg/day) by gavage, for 4 wk, and then throughout the subsequent period of behavioral training and testing. As shown previously, giving all three compounds caused highly significant (P<0.001)>

Power Napping

Sleep deprivation is chronic in our society and this has important implications for our health. Chronic sleep deprivation typically increases the production of proinflammatory cytokines. Chronic sleep deprivation will induce increased production of cortisol and interleukin 6. Both have a number of functions in physiology.

Cortisol is a key stress hormone that is important in suppressing excessive inflammatory responses and helping us to maintain alertness. Throughout the 24 hour period both cortisol and interleukin 6, along with a host of other physiological mediators, vary in accordance with our circadian rhythms. Cortisol rises in the early hours of the morning, helping us to wake up, climbs through the morning, then starts a gradual decline through the evening and night. At basal physiological levels it plays important roles.

Interleukin 6 is a perplexing cytokine, it has been associated both with inflammatory and growth processes, my guess is that its function is contingent on the expression of inflammatory mediators like tumour necrosis factor. That is, in the presence of tumour necrosis factor at elevated levels, in can promote inflammation. It is worth noting that in this study at least the levels of tumour necrosis factor were largely unaffected.

In this study the human subjects were sleep deprived for a number of days and then allowed to nap for 2 hours. The effects were minor, statistically significant yes but physiologically significant? Not so sure about that. Napping does help but it cannot make up for maintaining good sleeping patterns.

The Lesson

Don't fall for the idea that you can catch up on sleep and no harm done. Sleep deprivation is a stressor and will impact your performance. Chronic sleep deprivation will do you no good at all. It will do the exact opposite. During the deepest phases of our sleep cycle growth hormone levels are elevated, and various repair processes come into play. As high cortisol is often found in depression, chronic sleep deprivation can pave the way for depression. Indeed it can be the final straw that breaks the camel's back. So if you are experiencing chronic sleep deprivation try to find ways to change that.

I take good quality sleep so seriously that I wear a sleep mask and ear plugs. This has a wonderful effect on my sleep cycle and I typically wake up wonderfully refreshed. A great change from years gone by when I would wake up feeling like death. I am a night owl who likes to stay up late, typically reading, studying, or just playing computer games. However I do make sure I get a good night's sleep and this has substantially improved my productivity and cognition.

If you're interested in learning about sleep and the importance of maintaining regular sleeping patterns I highly recommend The Promise of Sleep by William C. Dement and Christopher Vaughan. Dr. Dement commenced the Stanford Sleep Centre and is a leading authority on sleep. The text is very accessible. Here is a link to it.

You can download the full paper here.

Am J Physiol Endocrinol Metab 292: E253–E261, 2007.
Daytime napping after a night of sleep loss decreases sleepiness,improves performance, and causes beneficial changes in cortisol and interleukin-6 secretion

A. N. Vgontzas,S. Pejovic, E. Zoumakis, H. M. Lin, E. O. Bixler, M. Basta, J. Fang, A. Sarrigiannidis, and G. P. Chrousos

Daytime napping after a
night of sleep loss decreases sleepiness, improves performance, and
causes beneficial changes in cortisol and interleukin-6 secretion. Am J
Physiol Endocrinol Metab 292: E253–E261, 2007. First published August
29, 2006; doi:10.1152/ajpendo.00651.2005.—Sleep loss has been
associated with increased sleepiness, decreased performance, elevations
in inflammatory cytokines, and insulin resistance. Daytime napping has
been promoted as a countermeasure to sleep loss. To assess the effects of
a 2-h midafternoon nap following a night of sleep loss on postnap
sleepiness, performance, cortisol, and IL-6, 41 young healthy individuals
(20 men, 21 women) participated in a 7-day sleep deprivation experiment
(4 consecutive nights followed by a night of sleep loss and 2 recovery
nights). One-half of the subjects were randomly assigned to take a
midafternoon nap (1400–1600) the day following the night of total sleep
loss. Serial 24-h blood sampling, multiple sleep latency test (MSLT),
subjective levels of sleepiness, and psychomotor vigilance task (PVT)
were completed on the fourth (predeprivation) and sixth days (postdeprivation).
During the nap, subjects had a significant drop in cortisol and
IL-6 levels (P < 0.05). After the nap they experienced significantly less
sleepiness (MSLT and subjective, P < 0.05) and a smaller improvement
on the PVT (P < 0.1). At that time, they had a significant transient
increase in their cortisol levels (P < 0.05). In contrast, the levels of IL-6
tended to remain decreased for ~8 h (P < 0.1). We conclude that a 2-h
midafternoon nap improves alertness, and to a lesser degree performance,
and reverses the effects of one night of sleep loss on cortisol and IL-6.
The redistribution of cortisol secretion and the prolonged suppression of
IL-6 secretion are beneficial, as they improve alertness and performance.

Exercise and Brain Aging

There is now abundant research pointing to the beneficial effects of aerobic exercise on cerebral health. This recent study finds that taking up exercise can improve cognition and cerebral health. There is a striking relationship between cardiovascular and cerebral health. The reason for this is obvious: the brain consumes approximately 20% of our oxygen intake, so maintaining maximal blood supply to the brain is critical. One of the reasons Ginkgo Biloba works is because it reduces platelet activating factor, thereby improving cerebral circulation.

Exercise and do it often. You don't have to run marathons, in fact intense exercise can do more harm than good. Light exercise is okay but it is important to push yourself, just going for a casual walk is good but going for a brisk walk is much better.

Exercise effects on cognitive and neural plasticity in older adults
Kirk Erickson and Arthur F Kramer
British Journal of Sports Medicine (2008).
The abstract:

Older adults frequently experience cognitive deficits accompanied by deterioration of brain tissue and function in a number of cortical and subcortical regions. Because of this common finding and the increasing aging population in many countries throughout the world, there is an increasing interest in assessing the possibility that partaking in or changing certain lifestyles could prevent or reverse cognitive and neural decay in older adults. In this review we critically evaluate and summarize the cross-sectional and longitudinal studies that assess the impact of aerobic exercise and fitness on cognitive performance, brain volume, and brain function in older adults with and without dementia. We argue that six-months of moderate levels of aerobic activity are sufficient to produce significant improvements in cognitive function with the most dramatic effects occurring on measures of executive control. These improvements are accompanied by altered brain activity measures and increases in prefrontal and temporal grey matter volume that translate into a more efficient and effective neural system.

The Aging Brain

This study from the Neurobiology of Aging highlights the significance of white matter in the aging process of the brain. The news item can be read here. White matter is the extensive sheath that surrounds the long and not so long axons of nerve cells. The presence of white matter markedly improves the speed at which signals can traverse through long axons. The process of myelination is long and we can in our late 20's or even early 30's before this process is completed.



Myelin creation is not a one off event, it is subject to continual degradation and renewal. The cells that produce myeline are called oligodendrocytes, a type of glial cell. Unfortunately oligodendrocyte cells demonstrate some particular vulnerabilities to insult. In those with Multiple Sclerosis, a common autoimmune condition, the immune processes responds to various "danger signals" emitted by oligodendrocytes and this can establish an ongoing destruction of these cells and myelin production. The initial triggers for this condition remain unknown but there are a number of strategies that Multiple Sclerosis sufferers can undertake which may alleviate the progress of the condition.

As we age the balance between myelin degradation and renewal falls out of kilter, the result being that we start losing the myelin covering. Of interest is the association between dementias and changes in white matter, it may even be the case that in some individuals the destruction of myelin is so extensive as to initiate a series of inflammatory processes that in turn induce dementias.

There is an important lesson here. The brain controls the body, maximising cerebral health is critical to maintaining good health as we age.