I find it interesting he mentioned a new hypothesis based on how many decisions you make each day affecting your cognition. Bryan Johnson as far as I know reduced the amount of his decisions, finding something more ‘autopilot’ for his health, and maybe more things.
Part of the Transcript with sources
01:25
Caveman Features
Homo heidelbergensis | The Smithsonian Institution's Human Origins Program.
This early human species had a very large browridge, and a larger braincase and flatter face than older early human species. It was the first early human species to live in colder climates; their short, wide bodies were likely an adaptation to conserving heat.
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01:37Dramatically Different Uses for a Similar Brain
https://www.science.org/doi/10.1126/sciadv.aao5961
Our data show that, 300,000 years ago, brain size in early H. sapiens already fell within the range of present-day humans. Brain shape, however, evolved gradually within the H. sapiens lineage, reaching present-day human variation between about 100,000 and 35,000 years ago. This process started only after other key features of craniofacial morphology appeared modern and paralleled the emergence of behavioral modernity as seen from the archeological record. Our findings are consistent with important genetic changes affecting early brain development within the H. sapiens lineage since the origin of the species and before the transition to the Later Stone Age and the Upper Paleolithic that mark full behavioral modernity.
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UNLV Research: No, the Human Brain Did Not Shrink 3,000 Years Ago“We re-examined the dataset from DeSilva et al. and found that human brain size has not changed in 30,000 years, and probably not in 300,000 years,” Villmoare said. “In fact, based on this dataset, we can identify no reduction in brain size in modern humans over any time-period since the origins of our species.”
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01:53Pre Frontal Cortex and Decision Making
Various regions of the brain play crucial roles in decision-making. The prefrontal cortex, often referred to as the brain’s executive center, is heavily involved in higher-order thinking processes such as planning, reasoning, and decision making. Within the prefrontal cortex, the dorsolateral prefrontal cortex is particularly important for evaluating options and making choices based on past experiences and future goals. Additionally, the limbic system, which includes structures like the amygdala and the hippocampus, influences decision making by processing emotions and memories. Emotions, in particular, can significantly impact our choices, sometimes leading to decisions that defy rationality.
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Confirming that our ancestors had PFC:Evolution of prefrontal cortex - PMC.
Subdivisions of the prefrontal cortex (PFC) evolved at different times. Agranular parts of the PFC emerged in early mammals, and rodents, primates, and other modern mammals share them by inheritance. These are limbic areas and include the agranular orbital cortex and agranular medial frontal cortex (areas 24, 32, and 25). Rodent research provides valuable insights into the structure, functions, and development of these shared areas, but it contributes less to parts of the PFC that are specific to primates, namely, the granular, isocortical PFC that dominates the frontal lobe in humans. The first granular PFC areas evolved either in early primates or in the last common ancestor of primates and tree shrews. Additional granular PFC areas emerged in the primate stem lineage, as represented by modern strepsirrhines. Other granular PFC areas evolved in simians, the group that includes apes, humans, and monkeys. In general, PFC accreted new areas along a roughly posterior to anterior trajectory during primate evolution. A major expansion of the granular PFC occurred in humans in concert with other association areas, with modifications of corticocortical connectivity and gene expression, although current evidence does not support the addition of a large number of new, human-specific PFC areas.
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02:15Cavemen Spent A lot of Time at Camp
Homo sapiens | The Smithsonian Institution's Human Origins Program.
or millions of years all humans, early and modern alike, had to find their own food. They spent a large part of each day gathering plants and hunting or scavenging animals. By 164,000 years ago modern humans were collecting and cooking shellfish and by 90,000 years ago modern humans had begun making special fishing tools. Then, within just the past 12,000 years, our species, Homo sapiens, made the transition to producing food and changing our surroundings. Humans found they could control the growth and breeding of certain plants and animals. This discovery led to farming and herding animals, activities that transformed Earth’s natural landscapes—first locally, then globally. As humans invested more time in producing food, they settled down. Villages became towns, and towns became cities. With more food available, the human population began to increase dramatically. Our species had been so successful that it has inadvertently created a turning point in the history of life on Earth.
– – –The paleolithic diet contains lean meat, nuts, olive oil, fresh vegetables, and fruits.
How Mushrooms Fit Into Popular Diets | Mushroom Council.
The Paleo Diet, or Caveman Diet, is inspired by the foods that were available to and eaten by our hunter-gatherer ancestors. It’s focused on consuming whole foods like lean meats, fish, fruits, vegetables, nuts and seeds, and avoiding processed foods. Since mushrooms are one of the oldest known foods, it’s highly likely they were a favorite of cavemen, thus a natural fit for the Paleo Diet.
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03:56Modern Life Means A lot of Decisions
Rego, “Frontal Fatigue” page 152
We have already concluded that modern life is characterized by three demands, complexity, abstraction, and reformatting. How does this stress of modern life affect PFC? Many studies of PFC functions have looked at this question and reached a similar conclusion. Namely, that the PFC has an inverted U-Curve when you plot out function versus stress.
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04:0235K Decisions a Day
https://www.wsj.com/articles/the-cure-for-decision-fatigue-1465596928
. By some estimates, the average American adult makes 35,000 decisions a day. No wonder you’re tired. Soul-weary. Sucked dry. The kind of tired 10 hours of sleep can’t fix.
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04:06200 Decisions About Food Per Day
https://journals.sagepub.com/doi/10.1177/0013916506295573
How aware are people of food-related decisions they make and how the environment influences these decisions? Study 1 shows that 139 people underestimated the number of food-related decisions they made—by an average of more than 221 decisions. Study 2 examined 192 people who overserved and overate 31% more food as a result of having been given an exaggerated environmental cue (such as a large bowl). Of those studied, 21% denied having eaten more, 75% attributed it to other reasons (such as hunger), and only 4% attributed it to the cue. These studies underscore two key points: First, we are aware of only a fraction of the food decisions we make. Second, we are either unaware of how our environment influences these decisions or we are unwilling to acknowledge it.
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05:20Neurons
MIT School of Engineering | » What are thoughts made of?
When you read these words, for example, the photons associated with the patterns of the letters hit your retina, and their energy triggers an electrical signal in the light-detecting cells there. That electrical signal propagates like a wave along the long threads called axons that are part of the connections between neurons. When the signal reaches the end of an axon, it causes the release of chemical neurotransmitters into the synapse, a chemical junction between the axon tip and target neurons. A target neuron responds with its own electrical signal, which, in turn, spreads to other neurons. Within a few hundred milliseconds, the signal has spread to billions of neurons in several dozen interconnected areas of your brain and you have perceived these words. (All that and you probably didn’t even break a sweat.)
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05:37Glutamate
The Principles of Nerve Cell Communication - PMC.
Communication among neurons typically occurs across microscopic gaps called called synaptic clefts. Each neuron may communicate with hundreds of thousands of other neurons. A neuron sending a signal (i.e., a presynaptic neuron) releases a chemical called a neurotransmitter, which binds to a receptor on the surface of the receiving (i.e., postsynaptic) neuron. Neurotransmitters are released from presynaptic terminals, which may branch to communicate with several postsynaptic neurons.
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06:02Glutamate Buildup Makes You Feel Fatigued
At the end of the day, high-demand cognitive work resulted in higher glutamate concentration and glutamate/glutamine diffusion in a cognitive control brain region (lateral prefrontal cortex [lPFC]), relative to low-demand cognitive work and to a reference brain region (primary visual cortex [V1]). Taken together with previous fMRI data, these results support a neuro-metabolic model in which glutamate accumulation triggers a regulation mechanism that makes lPFC activation more costly, explaining why cognitive control is harder to mobilize after a strenuous workday.
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07:04
Interesting Paper on the Matter
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07:33Less Likely To Die of Heart Disease if You Siesta
Siesta in Healthy Adults and Coronary Mortality in the General Population
Results Among men and women, when controlling for potential confounders and using those not taking siesta as a referent category, those taking a siesta of any frequency or duration had a coronary mortality ratio (MR) of 0.66 (95% confidence interval [CI], 0.45-0.97). Specifically, those occasionally napping had a 12% lower coronary mortality (MR, 0.88; 95% CI, 0.48-1.60), whereas those systematically napping had a 37% lower coronary mortality (MR, 0.63; 95% CI, 0.42-0.93). Among men, the inverse association was stronger when the analysis was restricted to those who were currently working at enrollment, whereas among women, a similar analysis was not possible because of the small number of deaths.
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The effects of napping on cognitive functioning - PubMedThe significant benefits of a brief nap, containing virtually no slow wave EEG activity, are not predicted by the present theory of homeostatic sleep drive (Process S). A new biological process (Process O) suggests that sleep onset followed by only 7-10 min of sleep can result in a substantial increase of alertness because it allows the rapid dissipation of inhibition in the ‘wake-active’ cells associated with the ‘sleep-switch’ mechanism rather than the dissipation of Process S.
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The adaptive landscape of the ancestral human environments selected for a suite of genetic, behavioural and physiological traits, many of which persist in contemporary human populations. The transition to modernity [1] rapidly reshaped these environments, yet the slower rate of biological evolution limits phenotypic change. This results in evolutionary mismatch, defined here as the phenomenon by which previously adaptive alleles are no longer favoured in a new environment (Fig. 1). This definition operates across space and time, while other uses of mismatch are applied over the life course [2, 3].
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11:27
“Why We Sleep” page 25The second is sleep pressure. At this very moment, a chemical called adenosine is building up in yoru brain. It will continue to increase in concentration with every waking minute that elapses. The longer you are awake, the more adenosine with accumulate. Think of adenosine as a chemical barometer that continuously registers the amount of elapsed time since you woke up this morning.
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11:52
Open for Discussion: Caffeine - American Chemical Society.Caffeine is structurally similar to adenosine, found in our brains. Both molecules are water and fat soluble so they easily cross the blood-brain barrier. In the brain, adenosine protects us by slowing nerve cell activity. Due to its similar structure, caffeine binds to the adenosine receptor
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12:06
Why We SleepWe now understand why. For the entire time that caffeine is in your system, the sleepiness chemical it blocks (adenosine) nevertheless continues to build up. Your brain is not aware of this rising tide of sleep-encouraging adenosine… once your liver dismantles that barricade of caffeine, you feel a vicious backlash.
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12:48Coffee Nap
When Is the Best Time to Drink Coffee?
There’s no scientific evidence that supports a “best time.” But a mid- to late-morning cup between 9:30 a.m. and 11 a.m. may help you reap the most coffee benefits. That’s when cortisol levels start to dip, and you’ll get the biggest bang from the effect of caffeine.
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13:41Chronotypes
https://www.sleepfoundation.org/how-sleep-works/chronotypes
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14:09Chronotype in our Genes
Why We Sleep - page 20
An adult’s owlness or larkness, also known as their chronotype, is strongly determined by genetics.
—On Screen: Matthews, “Why We Sleep”, 20
…humans evolved to co-sleep as families or even whole tribes, not alone or as couples… the benefits of such genetically programmed variation in sleep/wake timing preferences can be understood.
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15:17
How Memory and Sleep Are ConnectedA healthy adult’s sleep cycle consists of four distinct stages. The first two stages are considered light NREM sleep, and the third is deep (or “slow-wave”) NREM sleep. These three stages prepare your brain to learn new information the following day. Not sleeping or getting enough sleep can lower your learning abilities by as much as 40%.
During these NREM stages, the brain also sorts through your various memories from the previous day, filtering out important memories and eliminating other information. These selected memories will become more concrete as deep NREM sleep begins, and this process will continue during REM sleep. Emotional memories are also processed in the REM stage, which can help you cope with difficult experiences.
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Sleep and Hypertension - PMC.Both sleep deprivation and insomnia have been linked to increases in incidence and prevalence of hypertension. Likewise, sleep disruption attributable to restless legs syndrome increases the likelihood of having hypertension. Observational studies demonstrate a strong correlation between the severity of obstructive sleep apnea (OSA) and the risk and severity of hypertension, whereas prospective studies of patients with OSA demonstrate a positive relationship between OSA and risk of incident hypertension.
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The Neuroprotective Aspects of Sleep - PMChen one sleeps, the brain reorganizes and recharges itself, and removes toxic waste byproducts which have accumulated throughout the day. This evidence demonstrates that sleeping can clear the brain and help maintain its normal functioning. Multiple studies have been done to determine the effects of total sleep deprivation; more recently some have been conducted to show the effects of sleep restriction, which is a much more common occurrence, have the same effects as total sleep deprivation. Each phase of the sleep cycle restores and rejuvenates the brain for optimal function. When sleep is deprived, the active process of the glymphatic system does not have time to perform that function, so toxins can build up, and the effects will become apparent in cognitive abilities, behavior, and judgment. As a background for this paper we have reviewed literature and research of sleep phases, effects of sleep deprivation, and the glymphatic system of the brain and its restorative effect during the sleep cycle.
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16:11Screen Time Can Make You Less Sleepy
Blue light has a dark side - Harvard Health
While light of any kind can suppress the secretion of melatonin, blue light at night does so more powerfully. Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).
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16:58Good Sleep Recipe < Pulmonary, Critical Care and Sleep Medicine.
During sleep, adenosine is recycled and levels are reduced in the brain; less adenosine receptor stimulation leads to more alertness. In essence, the longer you’re awake, the more adenosine you accumulate, the more sleep pressure you acquire, and the more likely you are able to fall asleep at bedtime
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Brain may flush out toxins during sleep | National Institutes of Health (NIH).good night’s rest may literally clear the mind. Using mice, researchers showed for the first time that the space between brain cells may increase during sleep, allowing the brain to flush out toxins that build up during waking hours.
— – –The Neuroprotective Aspects of Sleep - PMC
Recently research states that there is a fluid filled channel which eliminates the toxins in the brain that allows the brain to have a clean slate to work from after one engages in the act of sleeping
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Important Sleep Resources