86 page psych document MCAT

webers Law

the threshold at which you are able to notice a change in any sensation is the just noticeable difference

absolute threshold of sensation

the minimum intensity of stimulus needed to detect a particular stimulus 50% of the time, at low levels of stimulus some subjects can detect and some can't. This is not the same as just noticeable difference because JND is the smallest difference that can be detected 50% of the time

subliminal stimuli

stimuli below the absolute threshold

The Vestibular system

-balance and spacial orientation

-canal is filled with endolymph and causes it to shift- which allows us to detect what direction our head is moving in, and the strength of rotation

otolithic organs (utricle and saccule)

Help us to detect linear acceleration and head positioning, can contribute to dizziness and vertigo

Signal detection theory

looks at how we make decisions under conditions of uncertainty, discerning between important stimuli and unimportant noise

bottom up vs top down processing

bottom up: stimulus influences out perception, process sensory information as it is coming in (built from smallest piece of sensory information)

Topdown: background knowledge influences perception ex. where's waldo. Driven by cognition (brain applies what it knows and what it expects to perceive and fill-in the blanks)

Gestalt principles

similarity

pragnanz

proximity

continuity

closure

similarity- items similar to one another grouped together

pragnanz- reality if often organized reduced to simplest for possible (olympic rings)

proximity-objects that are close are grouped together

Continuity- lines are seen as following the smoothest path

closure- objects grouped together seem as whole

Structure of the Eye

cornea

anterior chamber

pupil

lens

ciliary muscle

posterior chamber

retina

choroid

sclera

− Conjunctiva is first layer light hits

− Cornea - transparent thick sheet of tissue, anterior 1/6th.

− Anterior chamber - space filled with aqueous humour, which provides pressure to maintain shape of eyeball.

− Pupil is hole made by iris, which determines eye color

− Lens bends the light so it goes to back of eyeball.

− Suspensory ligaments, attached to a ciliary muscle. These two things together form the ciliary body, what secrets the aqueous humor.

− Posterior chamber Is area behind the ciliary muscle, also filled with aqueous humor.

− Vitreous chamber - filled with vitreous humour, jelly-like substance to provide pressure to eyeball.

− Retina is filled with photoreceptors.

• Macula - special part of retina rich in cones.

• Fovea - completely covered in cones, no rods.

− Choroid - pigmented black in humans, a network of blood vessels. Bc black all light is reflected.

− Sclera - whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball. Attachment point for muscles.

sensation requires

light--> neural impulse by a photo receptor

What is light

electromagnetic wave part of a large spectrum

EM spectrum contains everything from gamma rays tp AM/FM waves. Visible light is in the middle (violet 400-Red700

Rods and cones

rods are for night vision, normally rod is on when light hits turns off

when rod is off, it turns on a bi polar cell, which turns on a retinal ganglion cell, which goes into the optic nerve and enters the brain

cones see color, centered in the fovea

Phototransduction cascade

-when light hits rods and cones

a set of steps that turn it OFF

- inside rod there are disks stacked on top of each other. There is a lot of protein in the disks, one is rhodopsin. When light hits, it can hit the retinal in rhodopsin, and causes it to change conformation from bent to straight. then rhodopsin changes shape. This is the beginning of a cascade of events

• Transducin breaks from rhodopsin, and alpha part comes to disk and binds to phosphodiesterase (PDE).

• PDE takes cGMP and converts it to regular GMP. Na+ channels allow Na+ ions to come in, but for this channel to open, need cGMP bound. As cGMP decreases, Na channels closes.

• As less Na+ enters the cell, rods hyperpolarize and turn off. Glutamate is no longer released, and no longer inhibits ON bipolar cells (it's excitatory to OFF bipolar cells).

• So bipolar cells turn on. This activates retinal ganglion cell which sends signal to optic nerve to brain.

Photoreceptors (Rods and Cones)

− A photoreceptor is a specialized nerve that can take light and convert to neural impulse.

− Inside rod are optic discs, which are large membrane bound structures - thousands of them. In membrane of each optic disc are proteins that fire APs to the brain.

− Cones are also specialized nerves with same internal structure as rod.

− Rods contain rhodopsin, cones have similar protein photopsin.

− If light hits a rhodopsin, will trigger the phototransduction cascade. Same process happens in a cone.

differences between rods and cones

• 120 M rods vs. 6 million cones.

• Cones are concentrated in the fovea.

• Rods are 1000x more sensitive to light than cones. Better at detecting light - telling us whether light is present, ie. BW vision

• Cones are less sensitive but detect color (60% Red, 30% Green, 10% Blue)

• Rods have slow recovery time, cones have fast recovery time. Takes a while to adjust to dark - rods need to be reactivated.

visual field processing

how our brain makes sense of what we are looking at. Right side of body controlled by left side, vice versa

feature detection and parallel processing

− Color (cones, trichromatic theory of color vision), form (parvocellular pathway - good at spatial resolution, but poor temporal), motion (magnocellular pathway, has high temporal resolution and poor spatial resolution, no color)

− Parallel processing - see all at same time; simultaneous processing of incoming stimuli that differs in quality

Auditory structure part 1

− Need 1) pressurized sound wave and 2) hair cell

− Ex. In between your hands are a bunch of air molecules, and suddenly hands move towards each other, so space is a lot smaller.

− Air molecules are pressurized and try to escape, creating areas of high and low pressure - known as sound

hair cells first hit outer part of ear, known as the pinna. Then go to external auditory meatus, then hit eardrum.

as pressurized wave hits eardrum, it vibrates back and forth causing the malleus, incus, and stapes to also vibrate

stapes is attached to oval window, as it gets pushed, it pushes fluid and causes it to go around the cochlea

keeps happening until energy of sound wave is dissipated. Meanwhile hair cells in cochlea are being pushed back and for and send info to auditory nerve

General classification:

• From pinna to tympanic membrane is the outer/external ear.

• From malleus to stapes, middle ear.

• Cochlea and semicircular canals is the inner ear.

how are sound waves made

• Sound waves can be far apart or close together

• How close peaks are is the frequency.

• Different noises have different sounds

• You can listen to different frequencies at same time - if you add dif frequency waves together, get weird frequency. Ear has to break this up. Able to do that because sound waves travel different lengths along cochlea.

hair cells

specialized auditory receptor neurons embedded in the basilar membrane

Auditory structure part 2

− Stapes - moving back and forth at same frequency as stimulus. It pushes the elliptical window back and forth.

• There's fluid inside the cochlea which gets pushed around cochlea, and comes back around. Organ of Corti splits cochlea into 2.

− Cross section of Organ of Corti

• Upper and lower membrane, and little hair cells. As fluid flows around the organ it causes hair cells to move back and forth.

• The hair bundle is made of little filaments. Each filament is called a kinocilium.

• Tip of each kinocilium is connected by a tip link.

• Tip link is attached to gate of K channel, so when get pushed back and forth they stretch and allows K to flow inside the cell.

• Ca cells get activated when K is inside, so Ca also gets activated, and causes AP in a spiral ganglion cell which then activates the auditory nerve.

Auditory processing

Brain relies on cochlea to differentiate between 2 different sounds.

− Base drum has low frequency, whereas bees have high frequency.

− We can hear between 20-20000Hz.

− Brain also uses basilar tuning - there are varying hair cells in cochlea. Hair cells at base of cochlea are activated by high frequency sounds, and those at apex by low frequency sounds.

• Apex = 25 Hz, base = 1600 Hz.

• Only certain hair cells are activated and send AP to the brain - primary auditory cortex receives all info from cochlea.

• Primary auditory cortex is also sensitive to various frequencies in dif locations.

• So with basilar tuning, brain can distinguish dif frequencies - tonotypical mapping.

somatosensation

− Types of Sensation, Intensity, Timing, and Location

− Types: Temperature (thermoception), pressure (mechanoception), pain (nociception), and position (proprioception)

− Timing: Non-adapting, slow-adapting, fast-adapting.

− Location: Location-specific nerves to brain

adaptation vs amplification

Adaptation is change over time of receptor to a constant stimulus - downregulation

− Ex. As you push down with hand, receptors experience constant pressure. But after few seconds receptors no longer fire.

− Important bc if cell is overexcited cell can die. Ex. If too much pain signal in pain receptor (capsaicin), cell can die.

Amplification is upregulation

• Ex. Light hits photoreceptor in eye and can cause cell to fire. When cell fires AP, can be connected to 2 cells which also fire AP, and so on.

Somatosensory Homunculus

− Your brain has a map of your body - the cortex.

− This part of cortex is the sensory cortex - contains the homunculus.

− Info from body all ends up in this somatosensory cortex.

− If there was a brain tumor, to figure out what part it's in neurosurgeons can touch diff. parts of cortex and stimulate them. If surgeon touches part of cortex patients can say they feel it. Do it to make sure they aren't removing parts in sensation.

− This creates topological map of body in the cortex.

Proprioception

How can you walk in a pitch black room? You rely on your sense of balance/position -proprioception.

− Tiny little sensors located in our muscles that goes up to spinal cord and to the brain. It's sensitive to stretching.

− Sensors contract with muscles - so we're able to tell how contracted or relaxed every muscle in our body is

Kinaesthesia

is talking about movement of the body. Proprioception was cognitive awareness of body in space. Kinaesthesia is more behavioural.

− Kinaesthesia does not include sense of balance, while proprioception does.

pain receptor is called

nociception

temp receptor

thermoception

type of fibers for pain

− 3 types of fibres - fast, medium, slow.

• A-beta fibres - Fast ones are thick and covered in myelin (less resistance, high conductance)

• A-delta fibres -- smaller diameter, less myelin.

• C fibres - small diameter, unmyelinated (lingering sense of pain).

Pain also changes conformation of receptors - capsaicin binds the TrypV1 receptor in your tongue, and triggers the same response.

olfaction structure

Smell is also known as olfaction

− Area in nostril called the olfactory epithelium. Separating the olfactory epithelium from the brain is the cribriform plate. Above the plate is an extension from the brain - olfactory bulb - a bundle of nerves that sends little projections through cribriform plate into the olfactory epithelium, which branch off.

• At end of each connection are receptors, each sensitive to 1 type of molecule.

• Molecule travels into nose, binds one of receptors on nerve endings.

− Zoom in on olfactory bulb

• Imagine there's olfactory cell sending projection to olfactory bulb. There are thousands of types of epithelial cells, each with dif receptor. Say this one is sensitive to benzene rings.

• When it binds to receptor, triggers events that cause cell to fire. AP will end up in olfactory bulb. All cells sensitive to benzene will fire to one olfactory bulb - called a glomerulus.

• They then synapse on another cell known as a mitral/tufted cell that projects to the brain.

− The molecule binds to the GPCR receptor, G-protein dissociates and causes a cascade of events inside the cell. Binds to ion channel, which opens and triggers an AP.

Pheromones

Why do dogs pee on fire hydrant? There are molecules released in the urine, which can be sensed by other animals through the nose - pheromones.

− They're specialized olfactory cells.

− Cause some sort of response in animal smelling them.

− Pheromone is a chemical signal released by 1 member of the species and sensed by another species to trigger an innate response.

− Really important in animals, particularly insects - linked to mating, fighting, and communication.

Specialized part of olfactory epithelium in animals - the accessory olfactory epithelium. It sends projections to the accessory olfactory bulb.

− Within the accessory olfactory epithelium, you have the vomeronasal system.

− In vomeronasal system, there are basal cells and apical cells. They have receptors at tips.

− Triangle will come in and activate receptor on basal cell here. Basal cell sends axon through accessory olfactory bulb to glomerulus, which eventually goes to the amygdala.

• Amygdala is involved with emotion, aggression, mating etc.

− Humans have vomeronasal organ, but no accessory olfactory bulb.

Gustation

− We have 5 main tastes, localized on the tongue - bitter, salty, sweet, sour, and umami (ability to taste glutamate).

− Taste buds are concentrated anteriorly on the tongue. Taste buds can be fungiform (anterior), foliate (side), and circumvallate (back).

• In each taste bud are the 5 receptor cells that can detect each taste. Each taste can be detected anywhere on the tongue.

• Mostly on anterior part of tongue.

− Each receptor has an axon, which all remain separate to the brain. And they all synapse on dif parts of the gustatory cortex. Known as the labelled lines model.

• Ex. Glucose hits tongue, activates sweet cell (because it has sweet sensitive receptors), triggers cascade of events so cell depolarizes, and travels down axon to the brain.

• Glucose binds GPCR, conformational change, G-protein dissociates, opens ion channels, cause cell to depolarize and fire an AP

− Sweet, umami, and bitter cells GPCR receptors.

− Sour and salty rely on ion channels. They bind to receptor directly, ex. NaCl binds to receptor and causes ion channel to open, and + ions outside flow in. Cell depolarizes and fires an AP.

− What happens if we put salty receptor inside a sweet cell? Receptors in membrane bind to glucose. But let's insert a salty receptor. Since axon from cell leads to brain, if NaCl comes in, it activates the receptor, + ions go inside, sweet cell depolarizes and fires AP, and brain interprets it as a sweet signal.

States of Consciousness

− Consciousness is awareness of our self and environment - dif levels of awareness can be induced by external factors such as drugs or internal mental efforts. Range from alertness to sleep.

− Alertness - you're awake

− Daydreaming- feel more relaxed, not as focussed. Can also be light meditation (self-induced)

− Drowsiness - just before falling asleep/after waking up. Can also be self-induced in deep meditation.

− Sleep - not aware of world around you.4 main types (Each type oscillates at dif frequency)

sleep waves

• Beta (13-30Hz) - associated with awake/concentration. Increased stress, anxiety, restlessness. Constant alertness.

• Alpha waves (8-13 Hz) - in daydreaming. Disappear in drowsiness but reappear in deep sleep. During relaxation.

• Theta waves (7 Hz) - Drowsiness, right after you fall asleep.

• Delta waves (0.5-3 Hz) - Deep sleep or coma.

• EEGs can measure brainwaves

sleep stages

Your brain goes through distinct brain patterns during sleep. 4 main stages that occur in 90 min cycles

− (Order is from N1 -> N2 -> N3 -> N2 -> REM - Order within cycle goes How long each stage lasts depends on how long you've been asleep and your age)

First is non-rapid eye movement sleep (non-REM) - N1, N2, N3

− N1 (Stage 1)- Dominated by theta waves. Strange sensations - hypnagonic hallucinations, hearing or seeing things that aren't there.

• Ex. Seeing flash of light, or someone calling your name, doorbell, etc. Or the Tetris effect - if you play Tetris right before bed, you might see blocks. Also a feeling of falling - hypnic jerks. Theta waves.

− N2 (Stage 2) - deeper stage of sleep. People in N2 are harder to awaken. We see more theta waves, as well as sleep spindles and K-complexes.

• Sleep spindles help inhibit certain perceptions so we maintain a tranquil state during sleep. Sleep spindles in some parts of brain associated with ability to sleep through loud noises.

• K-complexes supress cortical arousal and keep you asleep. Also help sleep-based memory consolidation. Even though they occur naturally, you can also make them occur by touching someone sleeping.

− N3 (Stage 3) - slow wave sleep. Characterized by delta waves. Where walking/talking in sleep happens.

REM (rapid-eye movement) stage. Most of your other muscles are paralyzed. Most dreaming occurs during REM sleep, so paralysation inhibits actions. Most important for memory consolidation.

− Combination of alpha, beta, and desynchronous waves, similar to beta waves seen when awake.

• Sometimes called paradoxical sleep, because brain is active and awake but body prevents it from doing anything.

• Waking up during REM sleep prevents memory formation of the dream.

circadian rhythms

why you get sleepy in afternoon. They're our regular body rhythms across 24-hour period. Controlled by melatonin, produced in the pineal gland.

− Control our body temperature, sleep cycle, etc.

− Daylight is big queue, even artificial light.

− Also change as you age - younger people are night owls, but older people go to bed early.

Dreaming

− Everybody dreams during REM sleep. Can tell someone is dreaming because eyes are moving rapidly under eyelids, and brainwaves look like they are completely awake.

− Activity in prefrontal cortex during REM sleep is decreased - part responsible for logic. Why things in our things that defy logic don't seem weird.

Dream Theories - Freud and Activation Synthesis Hypothesis

Do our dreams have a meaning? Sigmund Freud's theory of dreams says dreams represent our unconscious feelings/thoughts. Like an iceberg.

− 1. What happens? Manifest content (Ex. Monster chasing you)

− 2. What is hidden meaning? Latent content (Ex. Job pushing you out)

• Can help us resolve and identify hidden conflict.

Activation Synthesis Hypothesis

− Brain gets a lot of neural impulses in brainstem, which is sometimes interpreted by the frontal cortex.

− Brainstem = activation, and cortex = synthesis.

− Our brain is simply trying to find meaning from random brain activity. Therefore might not have meaning.

Sleep Disorders

People with sleep deprivation might be more irritable and have poorer memory. Could be dangerous when it comes to flying airplanes or driving cars.

− Also more susceptible to obesity - body makes more cortisol, and the hunger hormone.

− Can also increase your risk for depression. REM sleep helps brain process emotional experiences, which can help protect against depression (not certain).

− Can get back on track by paying back "sleep debt"

• How much is enough sleep? 7-8 hours for adults. Varies with age and individual. Babies need a lot more.

More serious form - insomnia (persistent trouble falling asleep or staying asleep). Various medications but taking them too long leads to dependence and tolerance.

− Exercising or relaxing before bed can help

Other end of spectrum is narcolepsy - can't help themselves from falling asleep. Various fits of sleepiness, going into REM sleep. Can occur any time. 1 in 2000.

− Indications it's genetic, and linked to absence of alertness neurotransmitter.

Sleep apnea - 1 in 20 people. People with it are often unaware. Stop breathing while sleeping - body realizes you're not getting enough oxygen, wake up just long enough to gasp for air and fall back asleep without realizing. Can happen 100x/night!

− Don't get enough N3 (slow-wave) sleep.

− Snoring is an indication, or fatigue in morning.

Sleepwalking/sleep talking - mostly genetic, occur during N3 and are harmless. Occur more often in children (have more N3).

Breathing-Related Sleep Disorders

− Sleeping problems can arise from brain, airways, or lungs/chest wall.

− Obstruction to airways causes problems breathing at night

• Air going into nose/mouth reaches the lungs. Tissues around neck may block this airflow - snoring/gasping/pauses in breathing. Called an apnea (absence of airflow).

• Called obstructive sleep apnea, very common and gets worse as people get older.

• People are tired/sleepy and unrefreshed when they wake up.

• 5+ apneas an hour (measured by polysomnography)

− In the brain, called central sleep apnea. Presence of apneas without obstruction. Problem with the control system for ventilation.

• Cheyne-Stokes breathing (period of oscillations, then flat, etc.) pattern in polysomnography

− In lungs or chest wall, hyperventilation can occur (high pCÓ, low pÓ). Caused by medication/obesity. Chronically elevated pCÓ can lead to right-sided heart failure.

Hypnotism (and the 2 theories)

usually involves getting person to relax and focus on breathing, and they become more susceptible to suggestion in this state - but only if they want to. More alpha waves in this stage - an awake but relaxed state.

− Some use hypnosis to retrieve memories, very dangerous because memories are malleable. Can create false memories.

− 2 theories for how it works:

• Dissociation Theory - hypnotism is an extreme form of divided consciousness

• Social Influence Theory - people do and report what's expected of them, like actors caught up in their roles

− Refocused attention, so sometimes it's used to treat pain. Reduced activity in areas that process sensory input. Although it doesn't block it out, it might inhibit attention

Meditation

training people to self-regulate their attention and awareness. Can be guided and focused on something in particular, like breathing, but meditation can also be unfocussed - mind wanders freely.

− More alpha waves than normal relaxation in light meditation.

− In deep meditation have increased theta waves in brain.

• In people who regularly go to deep meditation, increased activity in prefrontal cortex, right hippocampus, and right anterior insula - increased attention control (goal of meditation).

− Can be helpful for people with ADHD, or in aging.

Depressants and Opiates

Depressants are drugs that lower your body's basic functions and neural activity, ex. Heart rate, reaction time, etc. The most popular depressant is alcohol.

• Think more slowly, disrupt REM sleep (and form memories), removes your inhibitions

− Barbiturates - used to induce sleep or reduce anxiety. Depress your CNS.

• Side effects are reduced memory, judgement and concentration, with alcohol can lead to death (most drugs w/ alcohol are bad)

− Benzodiazepines are the most commonly prescribed suppressant. Sleep aids or anti-anxiety

• Enhance your brain's response to GABA. They open up GABA-activated chloride channels in your neurons, and make neurons more negatively charged.

• 3 types: short, intermediate, and long-acting. Short and intermediate are usually for sleep, while long acting are for anxiety.

− Opiates are used to treat pain and anxiety. Ex. Heroine and morphine. NOT a depressant.

• Used to treat pain because they act at body's receptor sites for endorphins.

• Different class than depressants, even though overlapping for anxiety, rest act on GABA receptors while opiates act on endorphin Rs.

• Lead to euphoria, why taken recreationally

Stimulants

− Range from caffeine to cocaine, amphetamines, methamphetamines, and ecstasy. In between is nicotine.

− Caffeine (inhibits adenosine receptors) can disrupt your sleep. Nicotine also disrupts sleep and can suppress appetite.

• At high levels, nicotine can cause muscles to relax and release stress-reducing neurotransmitters (to counteract hyper alertness).

• Both physiologically addicting.

• Withdrawal symptoms from both. Like anxiety, insomnia, irritability.

− Cocaine is even stronger stimulant - releases so much dopamine, serotonin, and norepinephrine that it depletes your brain's supply. Intense crash and very depressed when it wears off.

• Regular users can experience suspicion, convulsions, respiratory arrest, and cardiac failure.

− Amphetamines and methamphetamines also trigger release of dopamine, euphoria for up to 8 hours.

• Highly addictive

• Long-term addicts may lose ability to maintain normal level of dopamine

Hallucinogens

− Ecstasy - synthetic drug both a stimulant and hallucinogen.

• Increases dopamine and serotonin and euphoria. Also stimulates the body's NS. Can damage neurons that produce serotonin, which has several functions including moderating mood.

• Causes hallucinations and heightened sensations, ex. artificial feeling of social connectedness.

− LSD - interferes with serotonin, which causes people to experience hallucinations.

• Hallucinations are visual instead of auditory

− Marijuana is also a mild hallucinogen. Main active chemical is THC, which heightens sensitivity to sounds, tastes, smells.

• Like alcohol, reduces inhibition, impairs motor and coordination skills.

• Disrupt memory formation and short-term recall.

• Stays in body up to a week.

• Used as medicine to relieve pain and nausea

Some hallucinogens are used for PTSD treatment. Allow people to access painful memories from past that's detached from strong emotions - so they can come to terms with it.

Homeostasis

is how you maintain temperature, heartbeat, metabolism etc.

− If you take amphetamines, body quickly tries to lower HR and get back to normal. Brain is smart about this.

• If regular drug user, might take it at same time of day.

• If you're cocaine addict, your brain starts to recognize external cues like room, needles, etc. and knows it's about to get big dose of drug. Brain tells body to get head start - lowers HR before you take drugs. Why you need higher dose over time.

− What would happen if you get those cues and don't get the drug? You get a crash.

− If you're in a new location but take same level of drugs, might get overdose.

Reward Pathway in the Brain

When you first experience pleasure, brain releases neurotransmitter called dopamine. Produced in the ventral tegmental area (VTA), in the midbrain.

− VTA sends dopamine to the:

• Amygdala

• Nucleus accumbens (controls motor functions)

• Prefrontal cortex (focus attention and planning)

• Hippocampus (memory formation).

• Nuc. Accum., amygdala and hippocampus are part of the mesolimbic pathway.

− Different stimuli active circuit to dif degrees.

− VTA releases dopamine and receptors uptake dopamine - amygdala says this was enjoyable, hippocampus remembers and says let's do it again, and nucleus accumbens says let's take another bite. Prefrontal cortex focuses attention to it.

• At same time dopamine goes up, serotonin goes down, partially responsible for feelings of satiation. Less likely to be satiated or content.

− Increased genetic risk.

− Biological basis comes from animal models

• Ex. Rats and drug experiment, rats keep increasing dosage. Or if sick drug + favorite food = avoids it, addictive drug + fav food = wants more.

− Addiction takes over rational mind.

Tolerance and Withdrawal

Tolerance means you get used to a drug so you need more of it to achieve the same effect.

− Ex. Just took cocaine, lots of dopamine in synapse. Post-synaptic neuron has receptors for dopamine. Long-term stimulation can lead to brain shutting down some receptor - same amount of drugs won't cause same high.

If you go through period of not having the drug, you experience withdrawal symptoms.

− Things less strong as cocaine won't give you as strong of an effect, so dopamine levels decrease and you feel depressed, anxious, etc. (varies).

− Will do whatever it takes to get that high.

− Once you've built up tolerance, need drug to feel "normal" again.

− However, with time and effort brain can reverse back.

Substance Use Disorders

− Drugs include alcohol, tobacco, cannabis, opioids (heroin/morphine), stimulants (cocaine), hallucinogens (LSD), inhalants, and caffeine

− We have to consider what happens when drugs enter the body and when they exit. 2 different processes: intoxication and withdrawal.

• Intoxication refers to behavioural and psychological effects on the person, drug-specific. Ex. "drunk" or "high"

• Withdrawal is when you stop after using for prolonged time.

− Can result in substance-induced disorders. Could be disorders of mood (mania/depression), anxiety, sleep, sexual function, psychosis (loss of contact with reality).

− Which can lead to substance use disorders. Causing real degree of impairment in life, at work, school, or home.

• How do you know? By looking at their usage. Are they using increasingly large amounts, stronger cravings, more time recovering from it, failing to cut back, affecting obligations at work/home/school?

• Second factor is presence of withdrawal.

• Also tolerance.

− With caffeine, can't develop substance-use disorder.

Treatments and Triggers for Drug Dependence

− Treatments address physiological + psychological symptoms.

To treat, detox. But sometimes require strong medications to address symptoms.

• For Opiates such as heroine act at neural receptor site for endorphins to reduce pain and give euphoria.

• Methadone activates opiate receptors, but acts more slowly, so it dampens the high. Reduces cravings, eases withdrawal, and can't experience the high because receptors are already filled.

• For stimulants like tobacco, medications replace nicotine by delivering low levels of nicotine through patch, or deliver chemicals that act on nicotine receptors in brain. In this case prevents release or reuptake of dopamine. Help reduce cravings.

• For alcoholics, meds block receptors in reward system of alcohol. Also reduce symptoms of withdrawal.

• Important to prevent relapse during this early stage by minimizing negative symptoms.

− Cognitive behavioural therapy

addresses both cognitive and behavioural components of addiction. Recognize problematic situations and develop more positive thought patterns and coping strategies, and monitor cravings. Long-lasting

− Divided Attention

doing two things at once you end up switching between tasks rather than doing them simultaneously.

selective attention

process of reacting to certain stimuli selectively as they occur simultaneously. There are two types of cues that can direct our attention:

• Exogenous - don't have to tell ourselves to look for them (Ex. Bright colors, loud noises, "pop-out effect")

• Endogenous (require internal knowledge to understand the cue and the intention to follow it, ex. A mouse arrow, or the cocktail party effect).

• Cocktail party effect

ability to concentrate on one voice amongst a crowd. Or when someone calls your name.

Inattentional blindness

we aren't aware of things not in our visual field when our attention is directed elsewhere in that field.

Broadbent's Early Selection Theory

− All info in environment goes into sensory register, then gets transferred to selective filter right away which filters out stuff in unattended ear and what you don't need to understand it (accents etc.), and finally perceptual processes identifies friend's voice and assigns meaning to words. Then you can engage in other cognitive processes.

• Some problems - if you completely filter out unattended info, shouldn't identify your own name in unidentified ear. Cocktail party effect.

Deutch & Deutch's Late Selection Theory

− Places broadband selective filter after perceptual processes. Selective filter decides what you pass on to conscious awareness.

− But given limited resources and attention, seems wasteful to spend all that time assigning meaning to things first.

Treisman's Attenuation Theory

− Instead of complete selective filter, have an attenuator - weakens but doesn't eliminate input from unattended ear. Then some gets to perceptual processes, so still assign meaning to stuff in unattended ear, just not high priority. Then switch if something important.

Spotlight model of attention

Selective attention - takes info from 5 senses, but don't pay attention to everything.

− Aware of things on an unconscious level

• Priming,

where exposure to one stimulus affects response to another stimulus, even if we haven't been paying attention to it.

• We're primed to respond to our name. Why it's a strong prime for pulling our attention.

Information processing model

proposes our brains are similar to computers. We get input from environment, process it, and output decisions.

− First stage is getting the input - occurs in sensory memory (sensory register). Temporary register of all senses you're taking in.

− You have iconic (what you see, lasts half a second) and echoic (what you hear, lasts 3-4 seconds) memory

Working memory

s what you're thinking about at the moment.

• Verbal info - any words + numbers in both iconic and echoic memory

• Is processed in the phonological loop.

• Visual + verbal info - Need coordination of the two - the central executive fills that role.

• Creates an integrated representation that stores it in the episodic buffer to be stored in long-term memory.

• Visual + spatial info are processed in the visuo-spatial sketchpad

− Magic number 7

can hold 7 +/- 2 pieces of info at a time. Why phone #s are 7 digits long.

− Explains the serial position effect (primacy and recency effects)

dual coding hypothesis

it's easier to remember words associated with images than either one alone.

− Can use the method of loci - imagine moving through

long-term memory

− Explicit Memory (Declarative) - are facts/events you can clearly describe.

• Anytime you take vocabulary test or state capitals you're using semantic memory (has to do with words). So remembering simple facts.

• Second type is episodic memory (event-related memories).

− Implicit memories (Non-declarative) involve things you may not articulate - such as riding a bicycle, procedural memories.

− Other is priming - previous experiences influence current interpretation of an event

Retrieval Cues

− Priming - prior activation of nodes/associations, often without our awareness.

• Ex. hearing apple and asked to name word starting with A

− Context - the environment you encode and take the test.

• Scuba divers who learned and tested on same place scored better than learned in one place and took test in another.

• But not always the case, if you can't take test in same place studying in different places gives you diff cues for retrieval - so multiple cues that will help you.

Retrieval Cues: Free Recall, Cued Recall, and Recognition

− Free recall - no cues in recalling.

• Better recalling first items on a list (primacy) as well as last few (recency). Harder in middle.

• Curve is called the serial position curve/effect

− Cued recall - give you "pl" for "planet".

• Get more retrieval cues, tend to do better than free recall.

− Recognition - best out of the 3 tests.

• Present two words, and say which one you heard.

− Source monitoring Error

memory error where source of memory is incorrectly attributed to a specific recollected experience (when people recall information they often forget the information's source) -

• Ex. angry with someone but forgot it happened in a dream. Or recognize someone but don't know from where.

Decay

when we don't encode something well or don't retrieve it for a while, we can't at all anymore. Connections become weaker over time. Initial rate of forgetting is high but levels off over time.

interference

− Retroactive - new learning impairs old info (ex. Writing new address)

− Proactive - something you learned in past impairs learning in future (Ex. New password).

Alzheimer's Disease

Neurons die off over time. Earliest symptoms are memory loss, attention, planning, semantic memory, and abstract thinking. As it progresses, more severe language difficulties and greater memory loss, emotional stability and loss of bodily functions. Cause is unknown - have buildup of amyloid plaques in brain.

Korsakoff's Syndrome

caused by lack of vitamin B1 or thiamine. Caused by malnutrition, eating disorders, and especially alcoholism.

− Thiamine converts carbohydrates into glucose cells need for energy. Imp for neurons.

− Damage to certain areas causes poor balance, abnormal eye movements, confusion, and memory loss. At this stage called Wernicke's encephalopathy - precursor to KS. If diagnosed in time can prevent further damage. If untreated, will progress to Korsakoff's. Main symptom is severe memory loss, accompanied by confabulation (patients make up stories to fill in memories).

− Treatment is healthy diet, abstain from alcohol, take vitamins, and relearn things.

Retrograde amnesia

is inability to recall info previously encoded,

anterograde amnesia

is inability to encode new memories.

Piaget's Stages of Cognitive Development

Piaget argued children weren't miniature adults. Believed they actively construct their understanding of world as they grow.

− Sensorimotor stage (0-2 years) - smell, hearing, touch etc. + active

• Also develop object permanence - don't realize objects still exist if they can't see them. Can also use accommodation to acquire knowledge about novel experiences.

− Preoperational stage. (2-7 years)- When children are going to develop/engage in pretend play.

• Very egocentric - no empathy.

− Concrete operational stage. (7-11 years ) -Learn idea of conservation.

• Can do test to find out if they're in this stage - take 2 glasses with same amount of water, pour one into short fat glass and other into tall skinny glass, and ask child which one has more. Before this stage will say tall glass, but once they reach concrete operational stage, have same amount of water.

• Also begin to learn empathy.

− Formal operational stage (12+) - reason abstract consequences, and reason consequences. Where sophisticated moral reasoning begins to take place.

methods we can imply in problem solving:

1. Trial + error - not the most efficient.

2. Algorithm - logical procedure of trying solutions till you hit the right one.

3. Heuristics - mental shortcut to find solution quicker than other 2, ex. Focusing on one category of solutions.

• Means-end analysis - we analyze main problem and break it down into smaller problems, and reduce differences between problem and goal.

• Working backwards - start with goal and use it to suggest connections back to current. Used in mathematical proofs.

4. Intuition - relying on instinct. High chance of error.

• Fixation - getting stuck on a wrong approach. What happens might be insight - that aha moment. Or can let problem incubate - insight comes after some time.

• Type I error = false positive

• Type II error = false negative

Availability vs. representativeness

• Availability = actual memories in mind

• Representativeness = not thinking of exact memories, thinking of a prototype of idea.

Biases that prevent us from making correct decision

Overconfidence - ex. Going into test without knowing a lot of info.

− Could be due to fluency during studying.

2. Belief perseverance - ignore/rationalize disconfirming facts

− Ex. During elections ignore facts about someone you like.

3. Confirmation bias - seek out only confirming facts.

− Ex. Only read stories about how wonderful candidate was.

Framing effects - how you present the decision. Ex. Disease that will kill 600 people, option A is 100% chance exactly 200 people saved, option B 30% chance all 600 saved. Which do you pick? OR A. 100% chance 400 die B. 1/3 chance no one dies and 2/3 chance 600 die.

− In first, you'd pick A. In second, you'd pick B.

Semantic Networks

concepts are organized in mind in terms of connected ideas. Parallel to how info might be stored in a computer. Links can be shorter for closely related ideas, or longer for less related ideas.

• First semantic network model was hierarchical - higher order to lower order categories.

• Ex. Animal -> bird -> ostrich.

• More specific characteristics like sings, long legs, stored at lower nodes. Can breathe at higher nodes.

• Longer it takes us to verify connection between nodes longer it takes for us to make that link.

− Not true for all animals/categories, ex. People verify pig is animal takes longer than pig is mammal. Therefore proposed modified semantic network.

Intelligence (IQ is Intelligence Quotient)

− A mental quality that allows you to learn from experience, solve problems, and use your knowledge to adapt to new situations. Use numerical scores to measure aptitude for those tasks and compare them to how well others do.

− One theory is there's 1 general intelligence.

• Evidence comes from fact people who score well on one test also tend to score well on other types of test, ex. Verbal and math.

• Factor underlying these consistent abilities is called g factor (g = general intelligence)

− Also support for theories of 3 intelligences - analytical (Academic), creative (generate novel ideas and adapt), practical (solve ill-defined problems).

• IQ score measures only analytical intelligence.

− Another way is 2 major categories - fluid and crystallized intelligence

• Fluid is ability to reason quickly and abstractly.

• Tends to decrease as we move into older adulthood

• Crystallized refers to accumulated knowledge and verbal skills.

• Usually increases or stays same into adulthood

nature vs. nurture

How much is due to genes and how much due to environment/experiences?

− Study heritability by looking at correlation scores of twins who grew up in different homes, identical twins raised together, and fraternal twins raised together.

• Strongest correlation between identical twins (monozygotic) raised together.

• Twins raised apart not as high, suggesting environment component.

• Fraternal twins (dizygotic) even lower, suggesting also a genetic component.

− No recipe for structuring environment to make a genius, even though we know environments that would impair intelligence.

Spearman's idea of general intelligence

single g factor responsible for intelligence that underlies performance on all cognitive tasks

Gardner's idea of 8 intelligences

differentiates intelligence into different modalities

Galton's idea of hereditary genius

human ability is hereditary

Binet's idea of mental age

how a child at a specific age performs intellectually compared to average intellectual performance for that physical age in years.

− Behaviorists

empiricist, believe language is just conditioned behavior.

BF Skinner's behaviourist model says infants are trained in language by operant conditioning.

− Nativists

rationalist, language must be innate.

- emphasizes innate biological mechanisms and that children are born with ability to learn language.

− All people have a language acquisition device (LAD, later renamed universal grammar) that allowed them to learn language (syntax and grammar).

− Idea that this ability exists - all languages shared same basic elements like nouns, verb, etc.

• This allows child to pick up on that. Goes along with idea there's a "critical period", thought to be from birth to age 9, the period of time a child is most able to learn a language.

− Materialist

look at what happens in the brain when people think/speak/write.

− Interactionist

emphasizes interplay between environmental cues and innate biology

Some languages only have 2 words for color. But does that mean we think about color differently? Great language debate.

− Universalism

thought determines language completely.

− Piaget

he believed once children were able to think a certain way, and then developed language to describe those thoughts.

− Vygotsky

anguage and thought are both independent, but converge through development.

• Eventually learn to use them at same time.

Learning theory (Skinner)

language is a form of behavior and is learned through operant conditioning

− Children aren't born with anything, only acquire language through reinforcement.

• Child learns to say "mama" because every time they say that, mom reinforces child. But doesn't explain how they can produce words they've never heard before.

Interactionist approach (Vygotsky)

believe biological and social factors have to interact in order for children to learn language. Childrens' desire to communicate with adults makes them learn language.

• Social role that language plays and human brain develops to be receptive to new language, and children are motivated to practice and expand vocabulary

− Broca's area

(speech production) located in the frontal lobe

• When broca's is damaged, people have trouble producing speech but understanding is unaffected. (Broca's/expressive aphasia)

− Wernicke's area

(understand language) located in the temporal lobe

• Wernicke's aphasia - words they make don't make any sense and cannot understand what others say, but they can hear words and repeat them back

• Left side

needed for language

• If you see object on left, won't be able to name it. Can pick it up with left hand (since right side controls left), but has to be in right visual field before brain can name it.

right side

needed for action/perception/attention.

Limbic System

− Responsible for storage/retrieval of memories, especially ones tied to emotions (serves as control for basic emotion and drives)

• Mnemonic: Hippo wearing a HAT. Hypothalamus, amygdala, thalamus, and hippocampus.