Saturday, July 23, 2016

Physics: Sound and Light

Things to note:
  1. Determine whether a wave is undisturbed, reflected, refracted, diffracted, or dispersed.
  2. Lenses and mirrors follow the three optics rules: the focal point rule, the object rule and the image rule. 
  3. To solve for the Doppler Effect: when a wave source and observer move towards one another, frequency increases--add Δf to fs to get fo. When a wave source and observer move away from each other, frequency decreases--subtract Δf from fs to get fo. 

Equations: 
  • v = fλ , where 'v' is velocity, 'f' is frequency, and 'λ' is wavelength
  • T = 1/f , where 'T' is period 

*Sound requires a medium to travel, while light does not. The velocity of a wave is dictated by the medium through which it travels, so when a wave travels from one medium to another, its velocity changes according to the features of the new medium. Again, mechanical waves require a medium in which to travel through, while electromagnetic waves such as light are able to travel in the absence of a medium. 

Two characteristics of a given medium determine the velocity of waves traveling through it: 
  1. The medium's elasticity, or resistance to change in shape
  2. The medium's inertia, or resistance to change in motion 
*The velocity of sound waves in a gas is limited by the average speed of the molecules within that gas. Sound waves move more quickly through hot gases than through cold ones. 

Remember, a frequency of a wave that moves from one medium to another does not change, but the velocity does. 

*Heaver and denser media tend to slow waves down, while "stiffer" media tend to speed waves up, because they have greater elasticity, which is caused by increasing intermolecular forces, which consequently move the waves along. 

In general: 

'v' of sound in solid > 'v' of sound in liquid > 'v' of sound in gas




Physiology: Nervous System (General)

Divisions of the brain:

  • Forebrain (Telencephalon & Diencephalon)
    • Diencephalon
      • Hypothalamus
      • Thalmus
    • Cortex
    • Sub-cortical areas
  • Midbrain (Mesencephalon)
    • Tectum & tegmentum
  • Hindbrain (Metencephalon & Myelencephalon) 
    • Cerebellum & Pons
    • Medulla oblongata

CNS:

  • White matter = Tracts/Pathways (Columns = many tracts)
  • Gray matter = Nuclei
PNS: 
  • White matter = Nerves
  • Gray matter = Ganglia

31 Spinal nerves: "812551"
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

*Cervical spinal nerves exit from above the respective vertebra. 
     -Spinal nerve root 1 from above C1, and spinal nerve root 2 from b/w C1 and C2
     -The rest of the spinal nerves (Thoracic, lumbar, etc.) emerge from below

-Spinal cord ends at L1

Dorsal roots - Sensory fibers from dorsal root ganglia (DS) 
     -Carries afferent information
Ventral roots - Motor fibers from anterior gray column of spinal cord. (VM)
     -Carries efferent information 

Plexuses:
Cervical plexus (C1-C4) 
     -Innervate the muscles and skin of the neck and shoulder
     -Phrenic nerve supplies motor action of diaphragm. That's why neck injuries are so dangerous. Can cause respiratory arrest.

Brachial plexus: 


Lumbar plexus: 
Innnervates anterior and medial muscles of thigh. 
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Order of meninges: 
Brain --> pia mater --> arachnoid membrane --> dura mater 

Epidural injections are steroid injections used to reduce the inflammation and pain associated with nerve root compressions. Can be caused by herniated discs, spinal stenosis and etc.
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Cranial Nerves:

I. Olfactory - Sense of smell
II. Optic - Sense of vision
III. Oculomotor - 4-6 muscles of eye (up & in), and contraction of pupil
IV. Trochlear - oblique muscle of eye (down & out)
V. Trigeminal - V1 opthalamic; V2 maxillary; V3 mandibular
VI. Abducens - Lateral rectus muscle of eye (abducts outwards) 
VII. Facial - Facial expressions; anterior 2/3 tongue; salivary and lacrimal glands
VIII. Vestibulocochlear - Equilibrium & Hearing
IX. Glossopharyngeal - poterior 1/3 tongue; muscles of swallowing; senses carotid BP
X. Vagus - Senses aortic BP, slows heart rate, 
XI. Accessory - Sternocleidomasteroid, trapezius, swallowing
XII. Hypoglossal - Innervation of tongue muscles

Locations in order, First 2 in Forebrain, second 2 in midbrain (brainstem), third 4 in pons (brainstem), last 4 in medulla (brainstem) 

Tests:
Olfactory - sniff coffee beans
Optic - Visual fields
Oculomotor - present eye with light for pupilary reflexes. Should move up & in. The eyes go down and out if there is a problem
Trochlear - Extraoecular movements. If eye can't go down & out, there is a problem 
Trigeminal - light touch, plus corneal reflex, and clench teeth and open mouth against resistance.
Abducens - If eye doesn't abduct, problem. The patient will go cross-eyed. To compensate they will turn their head to avoid double vision. 
Facial - Wrinkle forehead, smile, pucker, close eyes. Taste anterior 2/3 of tongue
Vestibulocochlear - Tuning fork
Glossopharyngeal - Gag reflex, tough, taste with posterrior 1/3 of tongue
Vagus - ??? Not in notes
Accessory - Rotate head and shrug shoulders against resistance
Hypoglossal - Stick tongue out straight 
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Sensory representation:

Modality - Receptor type to specific type of stimulus. 
     -Labeled line coding = Direct assocaition b/w a receptor and a sensation.
Location - Stimulation of a specific area defines the receptor's receptive field. 
Intensity - Distinguished by frequency of AP's 
     -Number of receptors = population coding
     -Frequency of AP's = frequencv coding
Duration - Time


Free dendritic endings - pain and temperature 
Emcapsulated dendritic endings - nerve endings wrapped in connective tissue  and serve as mechanoreceptors. 
  • Meissner's corpuscles - detect light touch
  • Merkel discs - Also light touch like Meissner's corpuscles 
  • Krause's End bulbs - detect fine touch in mucus membranes
  • Pacinian Corpuscles - Deep connective tissue, respond to vibration and deep pressure 
  • Ruffini's Corpuscles - Found in dermis to respond to continuous pressure

Tonic receptors - Adapt slowly or do not adapt at all. 
     -Ex: Muscle stretch receptors, joint proprioceptors 
CNS must continually get info about degree of muscle length and joint position. 

Phasic receptors - Rapidly adapting receptors 
     -Ex: Tactile receptors in the skin
Don't respond to maintained stimulus 

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Motor fiber types 



Sensory fiber types: 

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Proprioceptors: Provide information about joint angle, muscle length & tension. 
  • Skeletal muscles, joints tendons, ligmaents 
  • Muscle spindles
  • Golgi tendon organs
  • Joint kinesthetic receptors 
Ia sensory fibers = Annulospiral endings, muscle spindles (found throughout skeletal muscle)
II sensory fibers = Flower-spray endings, golgi tendon organs
Only type IV sensory fibers are unmyelinated

-Gamma efferent motor fibers let the brain preset the sensitivity of the spindle to stretch.

Muscle spindles detect changing length of muscle via contractions and stretches. 

Pain, temperature, coarse touch, tickles and itches cross the spinal level. Fine touch and pressure crosses at the medullary level. 


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Glutamate binds AMPA and NMDA resulting in AP, which transmit signals to higher centers.

Lateral spinothalamic - pain and temperature (cross at spinal cord)
Ventral (anterior) spinothalamic - coarse touch, tickle or itch (cross at spinal cord)
Medial lemniscus pathway - find touch, pressure (cross at medulla) (dorsal column) 

Conscious proprioception - Communicated by posterior column-medial lemniscus pathway. 
Unconscious proprioception - Communicated by dorsal spinocerebellar tract, to the cerebellum. 

Ascending and descending tracts in the white matter of the spinal cord in cross section: 


Major Ascending pathways for somatic senses: 
Spinocerebellar - proprioception from skeletal muscle to cerebellum of same side (don't cross) 
Dorsal Column - Discriminative touch sensation through thalamus to somatosensory cortex (cross in medulla) 
Spinothalamic - Nondiscriminate sensations (pain, temp pressure) through the thalamus to the primary somatosensory cortex (cross in spinal cord before ascending) 

Some Descending pathways

Pyramidal tracts: 
Lateral corticospinal - cross in pyramids of medulla; voluntary motor to limb muscles 
Central corticospinal - cross at spinal cord' voluntary to axial muscles

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E = CS^2 where S = Body weight, and C = Cephalization factor, and E = brain weight

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Reflexes: 
Rooting - reaction when infant's cheek is stroked
Moro reflex - startle response in reaction to sudden intense noise or movement
Grasping reflex - obvious
Sucking reflex - obvious

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Eyes open = Beta waves
Eyes closed = alpha waves

Sulcus - Groove and line
Gyrus - Hill and bump

Central sulcus - separates frontal and parietal loves. 
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Cerebral cortex:
Supplementary motor area - Complex patterns of movement (opening or closing hand) 
Premotor cortex - Important in orienting the body and arms toward a specific target
Posterior parietal cortex - Lies posterior to primary somatosensory cortex
     -If damaged, cannot process complex sensory information to accomplish purposeful movement.

Broca's area - in frontal lobe
Wernicke's area - in temporal-parietal lobes

Circumventricular organs - Parts of the brain that lack a BBB 

Pericytes - contractile cells that wrap around the endothelial cells of capillaries throughout the body. Allow the cells to regulate capillary blood flow. 

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Membrane equilibrium for potassium = -90mV
Membrane equilibrium for sodium = +60mV

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Conduction speed of electricity through neurons is proportional to square root of the diameter. 

Increasing diameter = Increase conduction velocity 

Decrease capacitance (through myelination) = Decrease amount of energy it takes to depolarize a membrane. 

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Tests to diagnose Multiple Sclerosis include lumbar puncture, including CSF oligoclonal banding. Also an MRI scan of the spine. 


---------------------------

Kinesin + Dynein = Fast axonal transport

Astrocytes take up and degrade glutamate and GABA. They also take up excess K+ from brain ECF.

Microglia release nerve growth factor which helps neurons and glial cells survive.

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NT's made from tyrosine = Dopamine, Noradrenaline, Adrenaline
NT's made from tryptophan = Serotonin, Histamine

Parkinson's disease - deficiency of dopamine
Schizophrenia - dopamine receptor abnormalities 
Norepinephrine though to be involved in etiology of bipolar affective disorders

1. Glutamate - Excitatory
  • Ionotropic
    • NMDA receptors (high permeability to Ca+)
  • Important in learning in memory
  • Neurotoxic if present in high doses for a long period of time. 
    • Neurons literally stimulated to death. 
  • AMPA is a non-NMDA-type ionotropic transmembrane receptor for glutamate
2. GABA - Inhibitory 
  • Selectively permeable to Cl- 
  • Benzodiazepines, barbiturates and alcohol augment effect. 
  • Decrease GABA inhibition = epilepsy 

Neuropeptides: 
Substance P - Transmits pain. 
Neuropeptide Y - Stimulates appetite and food intake 

NO and CO activates guanyl cyclase and cGMP 

H2S is a neuroprotectant against oxidative stress. It shows cardioprotective effects.

*Nicotinic receptor = Excitatory at neuromuscular junctions with skeletal muscle
*Muscarinic receptor = Inhibitory in cardiac muscle

Ionotropic receptors: 
  • Ion channels
  • Nicotinic receptors
  • Minimal amplification
  • Rapid
  • Glutamate and GABA act through these 
Metabotropic receptors: 
  • G protein-coupled receptors (GPCRs)
  • Muscarinic receptors
  • Large amplification
  • Not rapid 
  • Neuropeptides and biogenic amines act through these

Nicotine is an ACh agonist (ionotropic)
Curare is an ACh antagonist, and causes paralysis (ionotropic)

Muscarine mimics ACh (muscarinic) 
Atropine blocks ACh (muscarinic) 

Two types of muscarinic receptors:
M2: heart; opens K channels to hyperpolarize 
M1: intestine; closes K channels to depolarize 

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Adrenergic receptors 
alpha-receptor response = vasoconstriction
beta-receptor response = vasodilation

Opioid receptors belong to a family of 7 transmembrane GPCRs

To get rid of ACh = acetylcholinesterase
To get rid of Norepinephrine = MAO (monoamine oxidase)

Ion channels = fast EPSP
GPCRs = slow EPSP

Presynaptic inhibition = inhibits some response
Postsynaptic inhibition = inhibits all response

Long-Term potentiation (LTP) = Activity at a synapse induces sustained changes in quality or quantity of connections . Glutamate is key element in potentiation since it's the main excitatory NT. 

Myasthenia gravis (PNS) - Severe weakness of the muscle. Functional disorder at the synapse b/w the motor neuron and skeletal muscle. 
     -Antibodies block or reduce number of nicotinic ACh receptors

Parkinson's (CNS) - Decreased stimulation of motor cortex by the basal ganglia. Insufficient formation of dopamine 

Schizophrenia (CNS) - Increased dopamine activity in mesolimbic pathway

-Benzodiazepines facilitate GABA binding 
-Agonistic action of GABA may account for the sedative-hypnotic and anesthetic properties. 

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Sympathetic Nervous System = T1-L2
Parasympathetic Nervous System  = Cranial nerves III, VII, IX, X and emerge from sacral at S2-S4

Parasympathetic = ACh
Sympathetic = Norepinephrine 

Sympathetic = Long post-ganglionic neurons, postganglions release into adrenergic receptors, however, preganglions secrete ACh
Parasympathetic = Long pre-ganglionic neurons, postganglions release ACh, preganglions secrete ACh also

ACh is made from acetyl-CoA and choline
Catecholamines are made from phenylalening and tyrosine, in that order

Reserpine is a drug that blocks the transport of dopamine into vesicles. 

Nicotinic receptors = found on postganglionic cell bodies of all autonomic ganglia. 
Muscarinic receptors = found on effector cell membranes.

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Adrenergic receptor systems

Beta 1 = heart, adipose tissue, Renin release from JG cells
Beta 2 = vascular smooth muscle, airway smooth muscle 



Muscarinic receptors - cardiac conduction system and exocrine glands and smooth muscles in PNS
     -In CNS, sweat glands




Termination of NT activity - through COMT and MAO.




Friday, July 22, 2016

How to Develop an Extraordinary Memory (And be Able to Memorize Absolutely Anything)

What is informally known as 'The Art of Memory', materialized in the period of Hellenistic Greece, where treatises written on rhetoric and logic were highly valued by society. Famously, Aristotle's Rhetoric stands timelessly above the rest. Our great Method of Loci, which is to be talked about here, originated from this classical period.

The oldest physical known work we have mentioning the Method of Loci is from Roman politician and philosopher Cicero, from his work De Oratore, and from what many believe to be his work, Rhetorica ad Herennium dating back to 80-90 BCE. At least, from the part of the book that mentions memory, the method has not changed at all since ancient Greece. This Greek (and what was to be adopted as a Roman) tradition has been passed down through the scholars of the ages, undergoing only slight minor revisions and creating similar mnemonic variations.

The technique is so simple (and powerful) in fact, that many inadvertently use it, remember content with it that is kept in memory for years, don't even realize the power of the tool they have accidentally stumbled across, and misconstrue it as something that was a product of being able to remember it via luck, or via maintenance rehearsal. People who compete in world memory competitions for example, almost unanimously use this method to memorize information, which successfully accounts for speed and accuracy more than any other method of memorizing.


Now, finally, the key to developing an extraordinary memory is by employing the following:


The Image-Number System, Major System, & PEG System are all variations on the Method of Loci, so it is evidently best to define and describe the Loci system first:


The Method of Loci:

The Method of Loci is a mnemonic technique which bases its philosophy on two basic principles:

  1. The human brain is inherently terrible at memorizing abstract information, which may include anything numbers related (mathematics, equations, etc.), intangible concepts, facts about the world, people's names, and the list goes on. 
  2. The human brain is inherently incredible at memorizing locations, and therefore formats of locations. It may be of no challenge to you if I ask for you to recall a location of your childhood, a house perhaps, and ask you to recall the format of the house. It is most likely the case that you would be able to tell me without much effort where the bedrooms are, the kitchen, the bathroom, where the bed is in a bedroom, the cabinet, TV, bookshelf etc. Even though you may not have been there in years, the format is still crystal clear in your head. 

There is an important implication to these scientifically studied principles: New locations, through evolutionary adaptation, are automatically stored to long-term memory, or LTM, in only one impression, whilst virtually everything else, is not stored in the LTM, but rather stored temporarily in the short-term memory. Therefore, in order for information stored in the short-term memory to cross-over to the LTM, there must be a period of maintenance rehearsal performed by the learner, which more often than not may take a substantial amount of effort depending on the complexity of the information, and signals no guarantee that the information won't be forgotten in 2-3 weeks. 


This begs to be exploited (what is termed exaptations), as it's an incredible resource provided by our brain's method of encoding spatial information. In simplest terms, the Method of Loci involves mentally placing objects of association into places already stored into the LTM in order to memorize information. The protocol is simple:

  1. Select the information you want to memorize. For the sake of example, let's take a simple concept or two from the skeletal system: "There are three types of bone: Cartilaginous, cancellous (aka spongy), and compact. Cancellous bone houses bone marrow. Red bone marrow is marrow primarily made out of blood, and yellow bone marrow is marrow primarily made out of adipocytes (fat cells)." 
  2. Select a location that is in your long-term memory, and one which you have a clear mental picture of its format. (Take a bedroom of a house for example) 
  3. Take a mental note of the stations of the room, and order them in your mind. Stations can be any piece of furniture, or any item that characterizes a room, such as a painting, a shoe rack, a keyboard, etc. Usually it's much easier to go in one direction (left to right, or right to left) so that there is not much mental effort expended in "memorizing" the order of the stations. 
  4. Select the first station, and place an object (or more) that will serve as an "anchor" to the concept being selected for memorization. This object may either be strategically chosen as a phonetic anchor (such as using a pan to remind one's self of the pancreas) or an anchor of an already held association (such as using Shakespeare to remind one's self of sonnets). Since phonetic anchors have a substantially higher range of possibilities, it is usually the case that these are the best choices. It is similar to the situation when you forget somebody's name, but your friend gives you the first letter or syllable such as "Ja-" to jog your memory, which promptly lets you remember that the person's name is "Jason". This is exactly that, but at a much higher level since it involves images.  
    1. In this example, the first station is the bookshelf of the bedroom. (In reality, the bookshelf probably has books in them already, but for the sake of this method, you only need to remember that the bookshelf is there, so it is quite fine to delete all the books from the bookshelf in your mind to make space for the objects you are about to put in it) 
    2. An ear is placed on the top shelf of the bookshelf (an ear reminds me of cartilage, since an ear is made out of cartilage). This is an anchor of an already held association. 
    3. Next to the ear, is a textbook I own called "The Biology of Cancer". In this case, I know how the front cover of the textbook looks, and so it is very memorable to me. This is a phonetic anchor, because all I need is the "Can-" in "cancer" to remind of "cancellous bone." (Alternatively, since cancellous bone is also known as spongy bone, I could have used a sponge to remember spongy bone. However, something a bit more ridiculous would be more memorable, so instead of a sponge, it may be better to use something like Spongebob.) 
    4. Next to the textbook is a sign of the "contact" icon used on the iPhone. Again, this is a phonetic anchor, because "contact" sounds similar to "compact". This particular image may be difficult to memorize than the others because it's so banal. So, when greeted with something as mundane as a phone icon, engorge it and accessorize it to make it ridiculous, and therefore more memorable. In my case, I simply make it bigger so that it's almost as big as a road sign, and laminate it so that it looks like it can be preserved for a long time. Just for some morbidity, I scatter drops of blood around it, just to solidify it in my memory. 
    5. On the shelf below, I place a display case, as ones found in museums, housing two arrows made out of bone (bone arrow ≈ bone marrow). The first arrow is covered in red blood. (Red bone marrow is marrow primarily made out of blood) And the second arrow looks like it pierced human fat, which looks like a glob of yellow, squishy, lump-like substance. (Yellow bone marrow is marrow primarily made out of fat). 
  5. Since the location you picked is already in your LTM, and since any object mentally placed in that location will automatically go into your LTM as well, and since the objects you placed in those locations are now associated with the information being memorized, therefore, the information associated is now in the LTM as well, in one fell swoop.  
Reading it typed out may make it seem like a long and arduous process, but all that has really been done to memorize the information in the example was placing four images on a bookshelf. Once the images have mentally been thoroughly reviewed (which only takes a couple of seconds) and "solidified" in the imagination, it will be very hard to forget the information memorized.


At first, it may take a couple of minutes to come up with memorable and clever images to place on stations and review it in one's mind. It is important to note that since you're making an effort to place information into the LTM in one single action, there will be no energy expended in trying to memorize information the other way around, namely the most common way that people memorize, which is to crossover information from the short-term memory into the LTM via brute force and repetition, or rehearsal. If one takes a minute to time the two methods, one will quickly realize how much faster (and more effective) using the Method of Loci actually is, since you are actively preventing the possibility that the information may be forgotten, in which case no time will be wasted anymore in re-learning information in the future. This is a huge time saver. 

Of course, like all skills, as one gets acquainted with the method, one will become much faster in coming up with memorable images to put in their designated locations (or what are commonly termed memory palaces), and so memorizing information will become almost effortless, no matter how complex the information is, for complex information can always be broken down into its simple components, in which the loci principle will still apply.

I can only speak for myself when I say that the affect that this method has had on me is quite astounding. Using this method for a little over two months now, the information I memorized is enormous, with almost no effort expended or stress developed to retain said information. It simply sticks into the LTM without fail. Now given the nature on how the recalling process actually works, it is quite a unique experience when I imagine myself situated in the middle of one of my memory palaces, because I can literally "point to" and "see" all the information I put into the room. It is a strange and pleasurable experience, because I feel as if I now "own" the information, in the same way I own my clothing, books, electronics or wallet. Rather than the information being in some "dark abyss" inside my mind, floating around with no guarantee that I'll remember it in the next 3-4 weeks/months, the information is now organized and put into a "place", in the same way I know in what place my laptop or desk is in reality.

This is the Method of Loci best described in a nutshell.
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The Major System: 

The Major System is used solely to memorize numbers: birthdays, dates, phone numbers, account numbers, credit card numbers, address numbers, constant values, concentration values, stock market numbers, numbers in physiology, pharmacology, finance, economics, the list is endless.

The principle involves turning numerical digits into phonetic values, so that digits can be associated with consonant sounds. So if a digit is associated with a consonant sound, so is a string of digits associated with a string of consonant sounds. It then becomes possible to add vowels in the middle of these consonant sounds to make words that represent objects, which may then be placed into designated memory palaces.

The chart goes as follows:

0 = S,Z
1 = T, D
2 = n
3 = m
4 = r
5 = l
6 = Ch, Sh, J
7 = K, G
8 = F, V
9 = P, B

This is the standard chart that a majority of people use. It is the case that you can associate any consonant sound with any digit, so long as you are consistent and stick to the consonant sounds you associate with the digits.

For example, if you want to memorize the number: 77327576430949501408572, which is a random 23-digit number (in essence, the amount of numbers you would have to memorize in any debit or credit card, which includes the 16 digit code, the 4 numbers for the date, and the 3 numbers for the security code) provided by a random number generator, you can use the method to memorize the number (and store it into the LTM) in just a minute or two. (And if you're a veteran to the process, in only a couple of seconds)

You may want to break the number up into a digestible group of 2, 3, 4, or 5 so forming words in relation to the numbers may become as simple as possible.

If we take the first 5 digits we get:
7=K,G, 7=K,G, 3=m, 2=n, 7=K,G

Now if you're greeted with a number 3 for example, of course you pick the letter 'm' because that is the sound associated with 3. However with a number like 7, you have the option to pick either 'k' or 'g'.

Forming a string of consonant sounds for 77327 = k,g,m,n,k.

Adding vowels to 'kgmnk' we can get something like: "kage monkey" or "cage monkey". Note that the 'y' sound is associated as a vowel in this system, and that since the sound produced by 'k' (as in kangaroo) is the same sound produced by a hard 'c' (as in car), then the letter 'k' takes place of all hard 'c' sounds. Similarly, if a word that starts with a letter 'c' makes an 's' sound (as in the word ceramic), then the 's' will simply take over all of those 's' sounds that instead start with the letter 'c'.

Now, "cage monkey" are actually two distinct images: cage + monkey. Or, they can be one image, such as picturing the monkey inside of a cage. In any case, so long as you remember it as "cage monkey", they are now free to be put into any memory palace. (Let's say the couch of a living room).

Taking the next set of digits: 576430 = l,k,ch,r,m,s, these can be formed into "lucky charms".  So now place the lucky charms cereal box next to the cage monkey on the couch of the living room.

Taking the next set of digits: 94950140 = p,r,p,l,s,t,r,s, these can be formed into "purple stars". So now picture several shiny, floating, radiating purple stars, and place them next to the lucky charms.

Taking the last set of digits: 8572 = v,l,k,n, these can be formed into "volcano". So now picture an actual volcano (or it can be a fake volcano from a 3rd grade science project) next to the floating purple stars.


And that is the Major System in a nutshell. Instead of memorizing 23 random individual and abstract pieces of information in the form of digits, using the Major System, you need only recall 4 memorable pieces of information in the form of images, which are placed in designated loci (in this example, on the couch of a living room).
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The Image-Number System:

The Image-Number System is fairly simple, yet quite useful. The principle simply involves taking a digit such as '7' and forming an image out of that digit which looks enough like the digit to remind you of it.

For most of these digits, the images I am about to outline are also a standard, but you can come up with your own images as well. For example, the number '1' can be anything else that looks like a number '1', which is characterized by a straight line, like a pencil, a sword, etc.

0 = Dinosaur egg
1 = Spear
2 = Swan
3 = Open Handcuffs
4 = Flag
5 = Hook
6 = The trunk of an elephant
7 = Ax
8 = Snowman
9 = Floating Balloon

This can be creatively used as a tool to help remember information easier. For example, if I want to memorize a number in chemistry, like the Boltzmann constant (1.38064852 × 10^-23), I'll just use the Major System, easy enough. But if I want to refer to the actual number itself (like the number '1' or '4'), I'll use this Image-Number System.

An example: glyceraldehyde-3-phosphate = ice (glyc-) + cowhide (aldehyde) + open handcuffs (the number 3) + lighting match (because in spanish, a match = fosforo which to me is a phonetic anchor for phosphate)

So: glyceraldehyde-3-phosphate = Ice + cowhide + handcuffs + match. (The objects are all interacting with one another: I see the ice melting, and the water is getting on the cowhide. I see the handcuffs on top of the cowhide. I see that the match is lit, and the flames are slightly burning the handcuffs. This makes the image far more memorable) In any case, the point is that whenever I see open handcuffs in my memory palaces, I think the number 3, or whenever I see a swan, perhaps flapping its wings somewhere in my memory palaces, I think the number 2, and etc.

*I also find it useful for this system to be used for ordinals as well, such as 1st, 2nd, 3rd, etc.*

The principle can actually be generalized to symbols entirely. For example: the "≈" (approximately equal) symbol looks exactly like the symbol used to represent the air coming out of those hand dryers in public bathrooms. So I can use the image of a bathroom hand dryer any time I want to use the "≈" symbol when memorizing information. The "∆" (delta) symbol can be a pyramid (or a miniature pyramid), the "Ψ" (psi) symbol can be a giant pitchfork, the "α" (alpha) symbol can be a coiled-up snake, etc etc. etc. It's all up to the learner's imagination.


That is the Image-Number System in nutshell.
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The PEG System:

This is nothing new. All that is meant by a PEG system, is a system in which images are pre-memorized in order to aid learning of new information. This particular system is completely personal to the learner, and develops over time; also if you haven't already realized, the Image-Number System is in itself a set of pegs, where a "snowman" always means the number 8 (or 8th), and a "flag" always means the number 4 (or 4th).

As an example, my friend's themodynamics textbook is a peg that reminds me of thermodynamics. So whenever I see that particular textbook in one of my memory palaces, I think of the word "thermodynamics", or the concept of thermodynamics, because that's what the textbook will always mean according to my personal PEG system.

Combining all these systems makes memorizing effortless and fun, since the primary tool being used to store information is one's own imagination.

Last example, combining a peg + an image-number association:

  • Spear + thermodynamics textbook = 1st Law of Thermodynamics
  • Swan + thermodynamics textbook = 2nd Law of Thermodynamics 
  • Open handcuffs + thermodynamics textbook = 3rd Law of Thermodynamics
  • etc. 

That is the PEG System in a nutshell. In essence, pegs are best used for concepts that repeat constantly in a subject matter.
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To Conclude:

The 8 (Some people give a list of 7,8, or 9 depending on how they format it) ways that the brain memorizes information the most efficiently is through:

  • Visualization (Images, Places etc.) 
  • Association (Pan - Pancreas, Red flag - China, Ice cubes - Cold etc.) 
  • Out of the Ordinary Events  (Traumatic experiences, Insane experiences, Awesome experiences, Embarrassing experiences etc.) 
  • Rhythm (Song lyrics, Poetry etc.) 
  • Color (Adds vividness to memory. It's inherently easy to remember the color of objects.) 
  • Humor (Funny jokes, Dirty jokes etc.) 
  • Overview (It's easier to remember concepts in which one has a bird's eye view of said concept through contextual information) 
  • The 5 senses (Experiences hard-wire sensuous information to ameliorate memory recall, such as the smell of pizza, how it feels like to scratch a blackboard with one's nails, the sound of a bee's buzz near the ear, etc.) 

In essence, using these techniques will allow you to:

Picture a place and add objects (visualization) that are best associated with things you want to memorize (association). These objects ought to have vibrant colors, smells, textures etc. (color + the 5 senses) and should ideally be silly or ridiculous (humor). This will allow your "memory palace" to be extremely out of the ordinary in nature in comparison to other places you have been or haven't used yet (out of the ordinary events). Once you're done adorning your memory palace, you can then mentally "walk" through it and quite literally look at all the information you stored in those objects, whether it be backwards, forwards, starting in the middle, or any other way you want. This type of clever organization allows you easy access to the information that you need and experience instant recall (overview).

Quite evidently, these techniques combine 7 out of 8 of the best methods your brain uses to memorize information all in one system.
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Systematizing The Methods to Optimize Learning: 

In reality, it is up to the learner to come up with their own system to use the methods in the way they prefer to help reach their own intellectual goals. This is simply because everyone takes notes differently, learns differently, and uses different materials.

Given this, a list of tips & hints will do:


1) Make your objects as big, grand, bold, shiny and characteristic as you can, as well as silly and ridiculous as you can. These tend to be the most memorable.

2) Usually, it's best to pick an image that first pops into your mind when thinking about a concept. This is an insight on how you think, and most likely how you will think in the future when performing information recall. You can use it to your advantage.

3) If objects become "fuzzy", erase them/edit the memory palace and put in new and more memorable objects.

4) Experiment with a "magic number" of things to add on a station. This of course, varies with content and how much you can picture in your mental screen. Picture each object mentally as you add them to a station to see when it's a good idea to stop and move on to the next station. You don't want to put too many objects in one station. Remember, there shouldn't be any extra mental activity in using the Method of Loci. This is a tool, and the whole point of this is to reduce mental activity and stress to make memorizing easier.

5) Drawing your objects will help solidify them into your palace even more. The good news is that being Michelangelo is not required.

6) Make rules for yourself and stick to them. Making a list of these rules and keeping them handy will only serve you to help you even more. For example, I have a personal rule regarding order: if a person is holding an object, I always acknowledge the person first, and then the object.

7) Try not to pick palaces that are small in size or have low roofs. It can get mentally claustrophobic.

8) Draw/sketch the palace and list the stations before putting objects in them.

9) Rehearse palaces periodically (go through them in your head). They don't take much effort to rehearse and can be done while walking somewhere, while on the bus, or as you're staring at the ceiling before going to sleep.

10) A messy mind is a messy memory. Add information into memory palaces in a format that makes sense to you. For example: It's best not to add an object that represents a concept in chemistry and add two more objects that represent concepts in literature and music in the same room. That won't make too much sense. (Unless of course, there is a clever connection between the concepts that you know will allow you to more easily remember it).

11) Last but not least, these systems are in nature greatly personal. This is because everyone's imaginations are vastly different, and so everyone will use the system in vastly different ways. Given that, experimentation is the key to becoming veterans to the art of memorization, and thus becoming a strong and effective learner.