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Where Does The Brain Get Its Energy From

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Consciousness As A Physical Process Caused By The Organization Of Energy In The Brain

How Your Brain Makes Its Own Electricity
  • FOVOLAB, Cardiff Metropolitan University, Cardiff, United Kingdom

To explain consciousness as a physical process we must acknowledge the role of energy in the brain. Energetic activity is fundamental to all physical processes and causally drives biological behavior. Recent neuroscientific evidence can be interpreted in a way that suggests consciousness is a product of the organization of energetic activity in the brain. The nature of energy itself, though, remains largely mysterious, and we do not fully understand how it contributes to brain function or consciousness. According to the principle outlined here, energy, along with forces and work, can be described as actualized differences of motion and tension. By observing physical systems, we can infer there is something it is like to undergo actualized difference from the intrinsic perspective of the system. Consciousness occurs because there is something it is like, intrinsically, to undergo a certain organization of actualized differences in the brain.

Glucose Metabolism And The Regulation Of Cerebral Blood Flow

Under resting conditions, local CBF is highest in brain regions with the highest local glucose metabolism. All brain regions are metabolically active at all times, but there is a large heterogeneity among various brain structures. During functional activation, the increase in local CBF usually parallels the increase in CMRglc, whereas the increase in oxygen metabolism is much lower . However, there is at least one example where under peripheral somatosensory stimulation, local CBF in the ipsilateral cortex can decrease despite increased CMRglc .

Experimental studies show that direct glucose sensing mechanisms are unlikely to be involved in the activity-induced regulation of CBF. Neither hyperglycemia nor mild-to-moderate hypoglycemia significantly changes the blood flow responses to functional activation . In addition, during acute hypoglycemia, resting CBF only increases significantly when blood and brain glucose are dramatically reduced .

The consequences of impaired adaptation of CBF to CMRglc are under active investigation. Artificial reduction of the CBF response during functional activation had no impact on evoked neuronal activity in an acute experimental setting . However, it is assumed that chronic global hypoperfusion of the brain may be not only a consequence but also an early cause of neurodegeneration in vascular dementia and Alzheimers disease . Thus, fine-tuned CBF-CMRglc- CMRO2 regulation is indispensable for healthy brain.

Your Brain Uses 20% Of The Oxygen And Blood In Your Body

Your brain needs a constant supply of oxygen. As little as five minutes without oxygen can cause some brain cells to die, leading to severe brain damage. Also, the harder you think, the more oxygen and fuel your brain will use from your blood up to 50%.

Every minute, 750-1,000 milliliters of blood flows through the brain. This is enough to fill a bottle of wine or liter bottle of soda.

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Food For Thought: How To Feed Our Brains Better

The food choices you make every day affect your health and the health of our environment but American children are more likely to each french fries than vegetables.

The human brain is an incredibly sophisticated organ. It has around 100 billion neurons that send nerve impulses at speeds of around 250 miles per hour. But like any other part of the human body, the brain needs essential raw materials to function properly. Composed of about 73 percent water and weighing about three pounds, the brain is just two percent of the average persons body weight but uses 20 percent of our calorie intake. Keeping our brains fueled and healthy is crucial.

Carbohydrates And The Brain

Where Does The Human Brain Get Its Energy?

The main function of carbohydrates in your diet is to provide energy and fuel to your body, especially your brain. Carbohydrates break down into glucose in your body, which is then used as energy. Complex carbohydrates are carbs that break down more slowly in your system, providing a more gradual energy source than simple carbohydrates, which can cause spikes to your blood sugar and energy levels. Complex carbohydrates include fiber-filled fare like legumes, starchy vegetables and whole grains. Between 40 and 60 percent of your daily intake of calories needs to be from carbs, ideally fiber-rich sources of carbohydrates.

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How Is Your Brain Powered

The brain is one of the most energy-consuming organs. It represents only 2% of the weight of an adult but it uses 20% of the energy produced by the body. Efficient energy supply is crucial for the brain so that our memory, mobility and senses can function normally. On the occasion of the Month of the Brain in May 2013, ERC Advanced grantee, Prof. David Attwell at University College London explains the mechanisms through which the brain is powered. Understanding these mechanisms may allow the development, in the long-term, of innovative therapies for cerebrovascular disorders.

Computers need a power supply to process information, for example when typing a document or surfing the web. The same goes for the operations performed by our brain cells. With his BRAINPOWER project, Prof. David Attwell is setting out to understand how and where the energy supply of the brain is controlled. The brain is powered by the glucose and oxygen which are provided to it in the blood. Because nerve cells use lots of energy, when they are active they signal to nearby blood vessels, telling the vessels to dilate, in order to deliver more substrates for energy production. These are the mechanisms we are studying.

Glucose And The Brain: Improving Mental Performance

Glucose is a type of sugar which the brain depends on for fuel. Studies show that dips in glucose availability can have a negative impact on attention, memory and learning, and that administering glucose can enhance these aspects of cognitive function. The brain also uses up more glucose during challenging mental tasks. Therefore, it may be especially important to keep blood glucose levels at an optimum level for good cognitive function. Consuming regular meals may help to achieve this.

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Keep Track Of Your Activity And Diet

Although there are a several rules outlined above for optimal brain health, we are all different. The way you respond to certain foods is unique to you. So keep track of what you eat, how often you eat it, and how you feel after eating it. Something that can can give someone brain fog can be what gives you an extra boost of cognitive functionality.

Glucose Metabolism And The Regulation Of Cell Death

How the food you eat affects your brain – Mia Nacamulli

Glucose metabolism is evolutionarily linked to the regulation of cell death ,3a), and this link is tightly controlled in a similar fashion in many cell types, arguing for a universal role of co-regulated metabolic and apoptotic pathways. Neurons and cancer cells are among the cell types that rely almost exclusively on glucose metabolism for energy generation, and recent evidence suggests that these cells can use similar mechanisms to adapt to substrate deprivation and promote survival .

The connection between glucose metabolism and cell death

Hexokinase II , a hypoxia-regulated HK isoform in the brain, has been demonstrated to control neuronal survival depending on the metabolic state .3). HKII restricts or inhibits apoptosis in a variety of different cell types depending on whether or not it is bound to mitochondria , and on the availability of glucose . Furthermore, the capacity of HKII to phosphorylate glucose is involved in sensing the metabolic state of the cell . In addition, HKII elicits its antiapoptotic function through a molecular interaction with PEA15/PED . HKII activity protects against neuronal cell death after hypoxia and in the presence of oxidative stress . However, HKII increases neuronal cell death under glucose deprivation, thereby functioning as a molecular switch that regulates neuronal survival depending on the metabolic state. Importantly, the capacity of HKII to phosphorylate glucose and its interaction with PEA15 both mediate this effect .

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Glucose Metabolism: The Bioenergetic Basis For Neurotransmission

The largest proportion of energy in the brain is consumed for neuronal computation and information processing , e.g. the generation of action potentials and postsynaptic potentials generated after synaptic events , and the maintenance of ion gradients and neuronal resting potential . Additionally, glucose metabolism provides the energy and precursors for the biosynthesis of neurotransmitters . Importantly, astrocytic glycogen seems to be directly relevant for learning . Furthermore, the glycolytic end product lactate appears to play a role in long-term memory formation , but the exact mechanism has not yet been established. Lactate injections alter the intracellular redox state and pH due to co-transport of H+ with lactate, and lactate receptors may also play a role in linking brain energy metabolism and neurotransmission . However, oxidative metabolism both in neurons and astrocytes appears to contribute to sustained learning effects after training, and glycogen can supply carbon for synthesis of glutamate during learning .

Energy Dynamics In The Brain: Contributions Of Astrocytes To Metabolism And Ph Homeostasis

  • 1Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
  • 2Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
  • 3Centro de Estudios Cient√≠ficos, Valdivia, Chile
  • 4Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
  • 5Institute of Physiological Chemistry, University of Veterinary Medicine Hanover, Hanover, Germany

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Beta Oxidation/gluconeogenesis Or Fat Burning

A fat molecule consists of a glycerol backbone and three fatty acid tails. They are called triglycerides. In the body, they are stored primarily in fat cells called adipocytes making up the adipose tissue. To obtain energy from fat, the triglyceride molecules are broken down into fatty acids in a process called Lipolysis occurring in the cytoplasm. These fatty acids are oxidized into acetyl- CoA, which is used in the Citric acid/Krebs cycle. Because one triglyceride molecule yields three fatty acid molecules with 16 or more carbons in each one, fat molecules yield more energy than carbohydrates and are an important source of energy for the human body . Therefore, when glucose levels are low, triglycerides can be converted into acetyl-CoA molecules and used to generate ATP through aerobic respiration.

This need arises after any period of not eating even with a normal overnight fast, mobilization of fat occurs, so that by the morning most of the acetyl-CoA entering the Citric acid/Krebs cycle comes from fatty acids rather than from glucose. Following a meal, however, most of the acetyl-CoA entering the Citric acid/Krebs cycle comes from glucose from food, with any excess glucose being used to replenish depleted glycogen stores or to synthesize fats.

This is a SLOW, NOT IMMEDIATE ENERGY SOURCE but has a NET ENERGY PRODUCTION of over 100 molecules of ATP.

Is The Brain Fueled By Fat Protein Or Carbs

Brain Consumes More Oxygen than Rest of Body

The human brain consumes up to 20% of the energy used by the entire human body which is more than any other single organ. The brain represents only 2% of body weight yet it receives 15% of the cardiac output and 20% of the total body oxygen consumption.

Our brains create major nutrition demands on our bodies in order to function optimally. So is it best to fuel the brain with fat, protein, or carbohydrates?

The answer is none of these. Even though the brain is composed of 60% fat, it is designed to be fueled by glucose. The brain accounts for 25% of the total body glucose utilization.

How do we get glucose to the brain? There are two ways.

1. Glucose is the human bodys key source of energy. The breakdown of carbohydrates yields mono- and di-saccharides, most of which is glucose. If glucose is available, the body will use it first since it is easiest and quickest to metabolize.

Whole simple carbohydrates like raw fruit and whole complex carbohydrates like grains, legumes, and tubers are excellent sources of glucose for the brain. Refined carbohydrates can deprive the brain of glucose.

Glucose is virtually the sole fuel for the human brain, except during prolonged starvation. In starvation, ketone bodies generated by the liver partly replace glucose as fuel for the brain.

This energy-conserving quality is the primary reason that where physical performance is concerned, the simple carbohydrates found in whole, raw fruit are a better source of fuel than protein and fat.

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The Human Brain Contains Approximately One Hundred Billion Neurons

This is about the same as the number of stars in the Milky Way galaxy. These neurons are connected by trillions of connections, or synapses. Experts call this a neuron forest. Information runs between these neurons in your brain for everything we see, think, or do. These neurons move information at different speeds. The fastest speed for information to pass between neurons is about 250 mph. That being said, neurons only make up 10% of the brain.

Eat Foods On The Low End Of The Glycemic Index

The glycemic index ranks foods according to how they affect blood glucose levels. Those who have diabetes may be familiar with the index as they suggest those with diabetes also eat foods on the lower end of the glycemic index. Foods that are on the low end of the glycemic index include various vegetables , oatmeal, pasta, rice, barley, fruits, corn, potato, whole wheat, etc.

In addition to eating foods on the lower end of the glycemic index, make sure that you are taking in a lot of fruits, vegetables, and grains as they are the most plentiful source of glucose.

Here is a more comprehensive list of foods and their corresponding GI rating.

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Energetic Organization As The Cause Of Consciousness

In theory, we could account for all the highly complex processes occurring in the brain in terms of energy, forces and work, that is, as physical, chemical and biological processes. But the seemingly unassailable problem of how any of these processes might cause consciousness remains. The principle outlined here that there is something it is like, intrinsically to undergo differences due to the antagonistic action of energy, forces and work may offer a toehold in the slippery face of the problem. There is something it is like, intrinsically, to be a tense muscle that is different from being a relaxed muscle. There is something it is like, intrinsically, to be networks of neurons in fantastically complex states of actualized differentiation from other networks, with action potentials propagating through vast arrays of fibers. But all this something is it like-ness is not in itself sufficient for consciousness. Muscles are not conscious, and networks of neurons are active in the brain when we are in dreamless sleep or under anesthesia. What is it about the organization of energetic processes in the brain, as discussed in Section Consciousness and the Organization of Energetic Processing in the Brain, which determines the level of consciousness we experience?

Why Does The Brain Need So Much Power

After watching this, your brain will not be the same | Lara Boyd | TEDxVancouver

New study shows why the brain drains so much of the body’s energy

It is well established that the brain uses more energy than any other human organ, accounting for up to 20 percent of the body’s total haul. Until now, most scientists believed that it used the bulk of that energy to fuel electrical impulses that neurons employ to communicate with one another. Turns out, though, that is only part of the story.A new study in Proceedings of the National Academy of Sciences USA indicates that two thirds of the brain’s energy budget is used to help neurons or nerve cells “fire” or send signals. The remaining third, however, is used for what study co-author Wei Chen, a radiologist at the University of Minnesota Medical School, refers to as “housekeeping,” or cell-health maintenance.Researchers reached their conclusions after imaging the brain with magnetic resonance spectroscopy to measure its energy production during activity shifts. Chen says the technology, which has been around for three decades and is used to track the products of metabolism in different tissues, could prove instrumental one day in detecting brain defects or to diagnose tumors or precursors of neurodegenerative diseases early.

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The Cost Of Transient Changes In Activity

Brain activation can be distinguished both qualitatively and quantitatively from resting metabolic activity referred to above . To understand the unique qualitative features of brain activation, it is important, first, to recall how blood flow and oxygen consumption are related to each other in the human brain. This relationship is striking for its spatial consistency. It can be measured quantitatively with PET as the fraction of available oxygen used by the brain. This measurement is usually referred to as the oxygen extraction fraction and represents the balance between oxygen delivery and oxygen consumption. Researchers have come to appreciate the spatial uniformity of the OEF measured in a resting state when ongoing metabolic activity is relatively constant . This spatial uniformity in the OEF exists despite considerable variation in the ongoing oxygen consumption and blood flow within gray matter and an almost 4-fold difference between gray and white matter in both oxygen consumption and blood flow. This relationship is altered to a measurable degree in the normal brain only when areas briefly change their activity during specific behaviors .

Ketones As A Source Of Energy For The Brain During Development

It has now been recognized that fatty acids, especially medium-chain fatty acids that constitute up to 1020% of fatty acids contained in breast milk, are one of the main substrates used to produce SCFAs and maintain sustained ketosis in infants . MCFAs are either directly converted into KBs by -oxidation in the liver that will be taken up by the brain or they can be stored in adipose tissues and can be used later to support energy demands during a fasting period . Moreover, it is estimated that human milk contains around 1517% SCFAs, which are highly ketogenic and may support brain energy and anabolic needs immediately . Interestingly, body fat deposition during development is unique in humans the human fetus starts to accumulate fat in subcutaneous adipose tissues during mid-gestation and has 500600 g of subcutaneous fat at birth, while most mammals have a very limited amount of adipose tissues and, therefore, inability to store either MCFAs or SCFAs .

Fig. 3.
Fig. 4.

Ketone body synthesis. Fatty acids are converted to acetyl-CoA through -oxidation. Acetyl-CoA can then either enter the TCA cycle to generate ATP, or 2 molecules of acetyl-CoA are condensed in acetoacetyl-CoA. Acetoacetyl-CoA is then used to produce acetoacetate that can be used to produce either acetone or D–hydroxybutyrate. The figure has been adapted from .

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