Biohacking Your Brain's Health
https://www.coursera.org/learn/biohacking-your-brains-health
Week 1: Nutrition and the Brain
Week 2: Exercise and the Brain
Week 3: Meditation and the Brain
Week 4: Sleep and the Brain
Week 1: Nutrition and the Brain
Structural Anatomy of Our Brains
- Primate brains emerged 60 million years ago
- Through evolution brain size increased 3x
- Three main structures which added to the forebrain
- Reptilian complex
- Oldest
- Brain stem and cerebellum
- Controls respiration, heart rate, sensory feedback, autonomic functions
- Paleomammalian Complex now limbic system
- Social behaviour and rewards
- Neomammalian Complex
- Cerebral cortex
- Abstract thinking
- Language
- Other common traits
- Weights 3 pounds
- Consumes 25% blood flow
- Wrinkly surface increases surface area
- Gyri (bumps)
- Sulci (dips)
- Two hemispheres work together
- Left
- Right
- Subdivided into lobes
- Frontal
- Temporal
- Occipital
- Parietal
- Meninges
- 3 layer innervated tissue in skull
- Enveloping brain
- Capable of feeling pain
- Also has deep structures
- Outer cortex
- Limbic system
- Monitor outside world
- Avoid or want
- Basal ganglia
- Motivation
- Movement
- Sensory relay
- Other functions
- Takes outside simulations through sensory organs
- Eyes
- Nose
- Ears
- Responds through mainly motor system
- Voluntary movement
- Muscle contraction via motor neuron
- ms time scale
- Sensory system is activated by changes in environment
- Magnitude of sensation is related to number of receptors activated
- Greater stimulus equals more receptors activated and loger effect
- Non-painful is sensory adaptation, don't constantly feel socks
- Painful stimuli cause
- Potentiation/sensitization
- Gets worse as continues
- Protects skin from damage
- Neurons have single cell body
- Responsible for communication signal transmission between cells and hundreds of shorter outbound processes
- Communicate via synaptic transmission
- Dendrites (branches)
- Axon
- Carries electric signals away from neuron to another neuron (dendrite)
- Doesn't touch
- Action potential
- Converted to chemical message
- Glia (glial cells)
- Equilibrium
- Support and protect neurons
- Four main functions
- Surround neurons hold in place
- Provide nutrients + oxygen
- Insulate neurons from one another
- Destroy pathogens and remove dead neurons
- Chemical transmitters
- Glutamate
- Excitatory
- GABA
- Inhibitory
- Serotonin
- Norepinephrine
- Produced in brain stem, travels to different parts of brain
- Dopamine
- Reinforcing behaviour (also addiction)
- Motor modulation
- Lack of it (Parkinson's disease rigidity)
- Visual pathway
- Starts in eye retina
- Converted into electrical signal traveling to
- optic nerve
- Chiasm
- Optic tracts
- Optic radiations
- Visual cortex in occipital lobes
- Visual Cortex
- Decodes signal into crude pixelated picture
- Then sent to association visual cortex
- Interpreted with color, depth, edge...
- Motor cortex
- Posterior of frontal lobe
- Activation neuron carries info to brain stem, spinal cord to effector muscles
- Outgoing signal modulated by two loops controlling precision, speed, and other
- Basal ganglia
- Cerebellar
- Speech area (left hemisphere for most people)
- Near motor cortex
- Has sensory and motor area
- Starts with hearing sound
- Through ear
- Deciphered into words and comprehended
- Sent to Broca's area
- Motor center of speech
- Executive functions
- Interior frontal area
- Behavioural control, personality, emotions, thinking, planning
- Involved in neurodegenerative and neuropsychiatric disorder
- Brain stem
- Cables from higher cortical areas converge to or from spinal cord
- Autonomic functions
- Cerebelum
- 80% of brains neurons
- Motor coordination structure
- Comparitor of sensory feedback and that intended from cortext
- Cognition too
- Malleable organ
- Influenced by nutrition, sleep, exercise
Neurological Diseases and Nutritional Health
- Brain disorders
- Leading contributors to global disease burden
- Neurological and mental
- Many chronic and disabling
- BMI
- Correlated with metabolic and disease outcome
The History of Nutritional Research, 1950s-1980
- Correlation between country location and heart disease
- More fat = more disease
- Food pyramid
- Reduce fat
- Increased grains and sugar
The History of Nutritional Research, 1980s-Present
- More cholesterol = greater death
- Lower fat = higher death from cardiovascular
- Only age and mean blood pressure carry significant positive coefficients for strokes
- Long standing recommendation of low-fat diet was removed
- Now fat is not the concern, but rather sweets, processed meats, fast food, alcohol
What Happens When We Eat
- Protein remains same
- People started eating less fat and more carbohydrates like cereals
- Corn syrup is more potent form of sugar
- Protein breaks down to amino acids
- Carbs breaks down to glucose
- Fat to fatty acids
- All get broken down to acetyl CoA universal energy substrate in cell
- Processed in Kerb's cycle (citric acid cycle) to make ATP (pure energy used in cell functions)
- Consumption of carbohydrates and lesser degree protein results in insulin secretion by pancreas
- Insulin hormone widely known for effects on glucose, but does more
- Secretion is an energy switch for satiety, ready to use available energy from foods and to store energy
- Insulin make different cells in body take up glucose by binding to special receptors, most sugar is taken by muscles cells, but other cells use sugar too like liver fat and organs
- Tells fat stores to stop releasing fatty acids for energy because glucose is available
- Inhibits lipolysis (fat breakdown)
- Tells liver to stock up on sugar in glycogen form
- Sodium retention, water by the kidneys, insulin in receptors to open specialized channels for sugars to get in the cell
- In past we incorrectly thought when insulin didn't work, sugar is in blood outside cell causing high sugar and diabetes
- Now we know that insulin and receptor is fine but there is too much sugar in cell because of too much carbohydrate consumption
- Pancreas senses extra glucose and pumps more insulin which elevates amount of insulin in blood
- Body tries to use energy and stores it as glycogen in liver and muscles and stores it as fat called novolipogenisis which is carbs to fat
- Fat cells get bigger and deposit to other organs outside of fat tissue
- ectopic fat deposition
- Starts in liver, fatty liver, dangerous condition leading to liver failure
- Deposits in blood vessels and elsewhere
- Causes immune system activation, inflammatory response and blood vessels clogging
- Balance between vessels constriction and dilation is lost and inflamed blood vessels signal to platelets to heal inflammation, and plaque starts forming in blood vessels
- This is insulin resistance
- 10-20 years later, when diabetes surfaces, structure is already compromised
- Insulin is essential for metabolism in brain and promotes U cell formation in neurogenesis.
- Inhibits apoptosis (neuronal cell death)
- Balances long term potentiation and depression, important in learning and memory
- Modulates inflammatory responses in glial cells and promotes blood vessels dilation in brain causes enhanced cerebral profusion
- Interferes with metabolism, promotes inflammation, inhibits cleanup process of proteins from brain.
- Protein accumulation causes toxicity
- Alzheimer's Disease has accumulation of A-beta protein and Tau protein
- Interferes with learning process and causes cognitive decline
- Causes cell death and loss of brain tissue
- Parkinson's, resistance causes dysfunction in mitochondria, damaging DNA
- Also associated with strokes
- Beta cell dysfunction (cells that make insulin) strong correlation
- Also in mood disorders and depression
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