One SCFA in particular, called propionic acid, has been identified as a driver for abnormal behaviour that is related to both ADHD and the autism spectrum. This SCFA can alter metabolic and immune pathways, as well as gene expression, which can affect the functionality of the brain cells and their receptivity to neurotransmitters, as well as their ability to regenerate and regulate inflammatory responses. Certain strains of pathogenic bacteria, such as clostridia, have been implicated in producing large amounts of propionic acid. This strain of bacteria is naturally present in the gut, however, an overgrowth can occur when good bacteria levels are compromised and/or there is an acute infection. In addition, processed wheat and dairy products often contain propionic acid as a food preservative in the form of calcium propionate.
Surgeries – Here's another unpleasant surprise. You're probably thinking we're referring to a brain surgery, but that's not the only surgery that can influence the blood flow to your brain the bad way. For example, a heart surgery can cause hypoperfusion. How? Fat globules, which are released during these kinds of procedures, can find their way to your brain and disrupt the optimal blood flow.
Age discrimination is alive and well throughout the whole of the UK, a piece of legislation does nothing to ensure that people over the age of 50 get a fair crack of the whip when applying for employment, Employers dont need to give a reason for not employing a person over 50 all they need to say is that theyre unsuitable opr a more suitable candidate got the position, albeit they are usually younger!
Lost confidence.  If you can’t find your keys, much less get through your workday in a timely fashion without a slew of mistakes, you are going to lose confidence in both your brain and yourself.  When you cannot remember where you put things and it takes an absurd amount of effort just to do a simple task, you might question your very sanity.  As your confidence continues to nose-dive, you just end up making more and more mistakes.  It turns into a vicious cycle.
Nuts and seeds are terrific sources of vitamin E, which, according to a 2014 study, can help prevent cognitive decline and Alzheimer’s disease as you age. Other vitamin E-rich foods include eggs and cooked veggies. And it’s not just your brain that benefits from nuts; your heart will be happier too. Almonds, walnuts, cashews, Brazil nuts, pistachios, and peanuts have been linked to a decreased risk of cardiovascular disease, according to a Harvard study. Try these other vitamin E-rich foods.
Googling, you sometimes see correlational studies like Intake of Flavonoid-Rich Wine, Tea, and Chocolate by Elderly Men and Women Is Associated with Better Cognitive Test Performance; in this one, the correlated performance increase from eating chocolate was generally fairly modest (say, <10%), and the maximum effects were at 10g/day of what was probably milk chocolate, which generally has 10-40% chocolate liquor in it, suggesting any experiment use 1-4g. More interesting is the blind RCT experiment Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort11, which found improvements at ~1g; the most dramatic improvement of the 4 tasks (on the Threes correct) saw a difference of 2 to 6 at the end of the hour of testing, while several of the other tests converged by the end or saw the controls winning (Sevens correct). Crews et al 2008 found no cognitive benefit, and an fMRI experiment found the change in brain oxygen levels it wanted but no improvement to reaction times.

For illustration, consider amphetamines, Ritalin, and modafinil, all of which have been proposed as cognitive enhancers of attention. These drugs exhibit some positive effects on cognition, especially among individuals with lower baseline abilities. However, individuals of normal or above-average cognitive ability often show negligible improvements or even decrements in performance following drug treatment (for details, see de Jongh, Bolt, Schermer, & Olivier, 2008). For instance, Randall, Shneerson, and File (2005) found that modafinil improved performance only among individuals with lower IQ, not among those with higher IQ. [See also Finke et al 2010 on visual attention.] Farah, Haimm, Sankoorikal, & Chatterjee 2009 found a similar nonlinear relationship of dose to response for amphetamines in a remote-associates task, with low-performing individuals showing enhanced performance but high-performing individuals showing reduced performance. Such ∩-shaped dose-response curves are quite common (see Cools & Robbins, 2004)


Running low on gum (even using it weekly or less, it still runs out), I decided to try patches. Reading through various discussions, I couldn’t find any clear verdict on what patch brands might be safer (in terms of nicotine evaporation through a cut or edge) than others, so I went with the cheapest Habitrol I could find as a first try of patches (Nicotine Transdermal System Patch, Stop Smoking Aid, 21 mg, Step 1, 14 patches) in May 2013. I am curious to what extent nicotine might improve a long time period like several hours or a whole day, compared to the shorter-acting nicotine gum which feels like it helps for an hour at most and then tapers off (which is very useful in its own right for kicking me into starting something I have been procrastinating on). I have not decided whether to try another self-experiment.
This calculation - reaping only \frac{7}{9} of the naive expectation - gives one pause. How serious is the sleep rebound? In another article, I point to a mice study that sleep deficits can take 28 days to repay. What if the gain from modafinil is entirely wiped out by repayment and all it did was defer sleep? Would that render modafinil a waste of money? Perhaps. Thinking on it, I believe deferring sleep is of some value, but I cannot decide whether it is a net profit.
If this is the case, this suggests some thoughtfulness about my use of nicotine: there are times when use of nicotine will not be helpful, but times where it will be helpful. I don’t know what makes the difference, but I can guess it relates to over-stimulation: on some nights during the experiment, I had difficult concentrating on n-backing because it was boring and I was thinking about the other things I was interested in or working on - in retrospect, I wonder if those instances were nicotine nights.
Eugeroics (armodafinil and modafinil) – are classified as "wakefulness promoting" agents; modafinil increased alertness, particularly in sleep deprived individuals, and was noted to facilitate reasoning and problem solving in non-ADHD youth.[23] In a systematic review of small, preliminary studies where the effects of modafinil were examined, when simple psychometric assessments were considered, modafinil intake appeared to enhance executive function.[27] Modafinil does not produce improvements in mood or motivation in sleep deprived or non-sleep deprived individuals.[28]
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