Psych 1XX3

i lobe psych1xx3!

Development - define it

• changes and continuities that occur within the individual between conception and death

• Developmental psychologists are interested in how you change over time and stay the same

Maturation + Learning

Maturation: the biologically timed unfolding of changes within the individual according to that individual’s genetic plan

• influenced by environmental conditions that shape the genetically determined process

Learning: relatively permanent changes in our thoughts, behaviours and feelings as a result of our experiences

• Acquisition of neuronal representations of new information

• learning processes allow you to permanently store information through neural connections in your brain

• new representations guide strategies to respond to events + stimuli in the environment

• learning can make once controlled processes automatic (e.g look both ways before crossing the street)

Interactionist Perspective

• view that holds that maturation and learning interact during development

  • some essential systems must be in place before learning (e.g you need muscles before you can balance, and you can’t talk until your mouth and tongue develop)

  • learning from the environment also modulates maturation of human processes (e.g you need to interact with others and experience stimuli to have normal vision, speech motor and social skills)

Why do developmental psychologists focus on changes in infancy and childhood compared to any other time in the lifespan?

• changes that occur earlier in life are much more dramatic than those occurring later in life

• changes from birth - 5 yrs old are more noticeable compared to 40 yrs - 45 yrs

• developmental changes that occur in early yrs play a role in shaping who you become

What are the four methods used to study an infant’s mind through sensory capabilities?

1) Habituation procedure

2) Event-Related Potentials (ERPs)

3) High Amplitude Sucking Method

4) Preference Method

Habituation Procedure

Question it answers: “Can the infant tell the difference between 2 stimuli?”

-infants are interested in novel objects in the environment

-first, repeatedly show the infant the same stimuli while measuring responses like heart rate, breathing, head or eye movements

-when novel stimulus is presented, the infant’s responses will show a burst in activity

-but after repeated exposure the infant will return to baseline level responses (they still perceive the stimulus, it is just no longer interesting)

BUT when the stimulus is changed, they will show another burst in activity

• evidence of dishabituation, showing that infant is distinguishing the old and new stimulus

Example: can a child tell the difference between blue and green?

• show blue repeatedly, until baseline response, then show green!

• if they dishabituate, the infant can perceive the different stimuli

Habituation vs Dishabituation

Habituation: a decrease in responsiveness to a stimulus following its repeated

Dishabituation: and increase in responsiveness to a stimulus that is somehow different from the habituated stimulus

Event-Related Potentials (ERPs)

Question: how does the brain react to this stimulus?

• a measure of the brain’s electrical activity evoked by the presentation of stimuli

• Uses a special cap with array of electrodes

• Can be tricky with an infant

• electrodes detect changes in electrical activity across a population of neurons in the brain

• particular behaviour being measured evokes changes in various brain regions of interest

  • e.g visual info → activity in occipital lobe, auditory info → activity in temporal lobe

• Can be used with Habituation to provide behaviour and neural measures to understand infant sensory interactions with the environment

High-Amplitude Sucking

Question: does the infant like the stimulus?

• infant can control the sucking behaviour to a certain extent, uses a special pacifier

• first measure baseline sucking rate for the infant in the absence of stimuli

• during shaping procedure, infant is given control over stimuli

• if sucking is faster than baseline → switch activated, causes stimulus to be presented

  • can detect and LIKE stimulus = suck faster, to keep playing longer

  • DISLIKE = suck at baseline or slower, to end the presentation

Preference Method

Question: which of the two stimuli does the infant like more?

• child is put in a looking chamber to observe two stimuli

• researches can accurately measure the direction the infant is looking, to tell if more attention is being direction to one stimulus over the other

• Overall, infants prefer —> big patterns, lots of black and white contrast and faces

Equal Attention (what does it mean?) —> could mean no preference or lack of discrimination

• Preference method is often followed by Habituation procedure so we know that the stimuli can be discriminated

Competence-Performance Distinction

an individual may fail a task not because they lack those cognitive abilities, but because they are unable to demonstrate those abilities

• e.g if you are unaware that a child is pre-verbal, you may wrongly assume that they have no preference between two toys

Two Types of Research Methods - Longitudinal (what is it, potential drawbacks)

Longitudinal:

• researchers examine the ability abilities and characteristics of the SAME individuals repeatedly over some subset of their lifespan

  • test same people every year

  • track each person as they develop

  • uncover link between abilities earlier vs later in life

  • Find patterns common to all

Drawbacks:

1) Cost and Time — expensive and time consuming

2) Selective Attribution - some people may quit, become unfit to continue or die, resulting in biased samples that do not represent the OG population well

3) Practice Effects - changes in participants’ responses due to repeated testing, no natural development being studied

Two Types of Research Methods - Cross-Sectional Design (what is it, potential drawbacks)

• a developmental research design in which individuals from different age groups are studied at the same time

• doesn’t track over a lifespan

• can still uncover age differences in memory by comparing performances across different groups of age

  • e.g 30 yr olds do better than 50 yr olds

Drawbacks:

1) Cannot distinguish age effects from generational effects

• 50 year olds had less training with numbers than 30 yr olds, resulting in decreased memory perfomance

2) cannot directly access individual developmental change

• basically influences on trends in group data

What is the best type of developmental task?

Longitudinal + Cross-sectional = BEST

• combines strengths and weaknesses of both design types

Zygotes, Chromosome, Genes

Zygote: sperm enters ovum, creating a zygote with 46 chromosomes (23 from each parent)

• divides exponentially (2,4,16 cells)

Chromosome: thread-like structure made of deoxyribonucleic acid of DNA

Genes: segments of DNA which provide chemical code for development

• Each parent can produce more than 8 million genetic combos with their gametes, therefore you are on of 64 trillion genetically distinct offspring that your parents could have had

Monozygotic vs Dizygotic twins

Monozygotic twins: genetically identical, same egg and ova from zygote (zygote splits into 2)

• if two pairs of monozygotic twins had children, they will be cousins but FULL genetic siblings

• 50% identical

Dizygotic (fraternal) twins:

• no more similar than siblings

• share ~50% of genes

• 2 different sperm and ova, start as 2 different zygotes since conception

Genotype vs Phenotype

Genotype: an individual’s inherited genes

Phenotype: expression of an individual’s genotype in terms of observable characteristics

• expression of a genotype into a phenotype can follow several patterns of inheritance (think how children can have different eye colours from their parents)

Canalization Principle

• within a species, genotype restricts the phenotype to a small number of developmental outcomes

• some developmental traits are buffered or protected from variability in the environment

• All members of a species will share many phenotypic traits, even though they have different interactions with their surroundings

Range-of-Reaction Principle

• genotype establishes a range of possible phenotypes in response to different kinds of individual life experiences

• complex gene environment reactions

  • based on individual nutrition, exposure and genetics

Simple Dominant-Recessive Inheritance

• pattern of inheritance in which the expression of a trait is determined by a single pair of alleles (an allele is a specific form of a gene)

  • Homozygous - 2 identical genes, Heterozygous - 2 different alleles of a particular phenotype (dominant one is expressed, recessive is inherited and suppressed)

Polygenic Inheritance

• when expression of a trait is determined by the interaction of multiple genes

  • poly = multiple,

  • examples of traits —> height and weight are determined by a combination of genes

• No singular gene can account for most complex behaviours

Codominance

• When the expression of a trait is determined equally by 2 dominant alleles

• Produces phenotype that is a compromise between the 2 genes

  • e.g blood type —> two dominant alleles can be expressed (AB = blood type AB)

Sex Linked Inheritance

• when the expression of a trait is determined by genes on the X or Y chromosome

• X chromozome is larger and contains more genetic info than the Y chromosome and there are more X linked sex traits + disorders that exist

Why X-linked are recessive alleles expressed more often in males?

• females have 2 X chromosomes, so the phenotypic expression of the recessive allele occurs less frequently compares to males who only have one

• females become genetic carriers

• example of disorders: hemophilia (colour blindness)

Nature vs Nurture Debate - which contributes more?

Nurture:

• Watson —> a behaviourist suggested that with the proper environment, anyone could become a Dr. Musician, etc.

Nature:

• some scientists believe that who you are is predetermined by inherited genes and that the environment had a minimal effect

  • “If your parents are smart and attractive, you should be too”

• Debate is a little obsolete

• Scientists believe that genetics and environmental influences interact to produce complex traits

• They both contribute

Genotype/Environment Correlations

Passive:

• environment that parents choose to raise their child in is influenced by the parents’ own genes so it will likely complement the child’s genes

• most influential during early years (childhood)

Evocative:

• traits that we inherit affect how others react to and behave towards us

  • difficult temperament - more negative responses from caregivers

  • sunny disposition - more positive responses from caregivers

• influential during all periods of life

Active Genotype:

• our genotypes influence the kinds of environments we seek (e.g thrill seekers will find dangerous and active locations)

  • most influential later in life (more free-will, not surrounded by parents

Twin Studies with Intelligence

• genes play a larger role than environment in determining intelligence (IQ)

Synapses - how does it change from the beginning of life to now?

• We start with an excess which are later pruned

• brain circuitry is not made permanent at any age - our brain has plasticity/malleability, as you can learn stuff later in life

Experience expectant brain growth vs Experience dependent brain growth

Expectant:

• our brains have evolved to EXPECT a certain amount of environmental input, and with this input, out brains develop normally

• auditory input, visual input etc.

• sufficient stimulation leads to normal development

Experience:

• our brains develop according to our own personal experiences

• specific to each individual

• reflect subtle changes in brain structure across individuals

• unique to each person, can push you beyond normal development

Critical Period

• a window of opportunity within an individual’s development in which particular environmental stimulation is necessary in order to see permanent changes in specific abilities

• after the critical period, the same stimulation will not have the same benefits

  • example: with cats, if the kitten didn’t get exposure to visual stimulus in the first 6 weeks, it was unable to distinguish visual patterns

• Not as widely accepted or used

Sensitive Period

• developmental periods during which a specific type of learning takes place most easily

• less rigid than critical periods — if period passes, learning can still occur, its just more difficult

• flexibility in timing and type of stimulation is required for normal development

• brain maintans some residual capacity for change and growth through adulthood

example: there is a sensitive period for languages skills

Lamb and Leurgans (1979) Experiment

• Couples seem to have increased fertility after adopting a child

• Is this true

Results:

• 895 couples “at risk” for pregnancy and adoption

• ~32% (adoption) vs ~43% (no adoption) of getting pregnant

• Opposite of hypothesis

• Chances of having a child by not adopting resulted in a greater chance of getting pregnant

Marshmallow Test Takeaways

• Demonstrates development of Self-Regulation

• High restraint correlated with higher SAT scores, working memory , decreased drug use, divorce rates, etc. (delayed gratification = more success)

• Environment influences marshmallow test - children who were lied to, are lower socioeconomic status or are younger have a greater chance of eating the marshmallow

• being watched or having a timer lowers chance of eating a marshmallow

Preference for faces

• newborns will look at face shapes more than non face shapes

• Innate genetic preference

Does excessive stimulation lead to greater success later in life?

• even if you try to prove it, no benefit in keeping more neural connections alive because pruning occurs

• reduce input is detrimental, but extra stimulation isn’t better

• Also specifically - the Mozart effect isn’t real for babies (only tested in adults)

Describe the Brain

• Brain is wrinkled, soft and wet

• Size is abt a 3lb cantaloupe

• Made up 87 billion neurons

• makes up your personality, perception and memories

Rene Descartes vs our current understanding of the brain

• Scientist + Philosopher

• Believed mental processes of the mind are seperate from the physical processes of the brain

• Update -→ brain is hardware driven by the software of the mind

Neuron

• fundamental building block of the nervous system

• specialized for communication

  • organized into signalling pathways to communicate via synaptic transmission

• structure aids in function (receptive and transmission zone)

Describe the different regions of the neuron and their components

Receptive Zone:

• comprised of the dendrites and cell body

  • dendrites → extend from core of neuron, reach out to other neurons to receive signals to be relayed through dendritic branch to the cell body

  • cell body → carries genetic information, maintains structure and provides energy to keep neuron functioning

Transmission Zone:

• made of axon, axon terminal, terminal boutons

  • axon → long fibre, can vary in length

  • axon terminal → end of axon, another cluster of branches

  • terminal boutons → little feet that connect to another neuron’s receptive zone to move the signal further

Glial Cell

• provide structural support, nourishment, and insulation for nearby neurons - they make sure the neuron is function properly

• work together with neurons

• around neurons

• rest in a bath of ions, chemicals and blood

Action Potential - what is it?

• fundamental unit of communication for neurons

• relies on selective movement of ions in and out of the neuron

Describe the Cell Membrane (in general, at resting potential)

• selectively permeable — some ions can pass thru easily, others cannot

• membrane has protein channels that allow ions to pass through

• inside of neuron has a resting potential of -70mv relative to the outside

Describe the location of the 4 ions at resting potential - inside? outside?

Sodium - positively charged, mobile, start on the outside

Potassium - positively charged, mobile, start on inside

Negatively charged protein - immobile (too large), stay inside

Chloride - negatively charged, mobile, but stay outside because the negatively charged proteins repel them

Important Channels (3)

Voltage Gated Sodium Channel:

• closed while resting

• flow into the cell but only at low concentrations

• Sodium mostly outside

Ligated Sodium Channel: - not that important

• only open when interacting with chemical or lygon

Potassium Leak Channel:

• “tap that’s always on”

• allow positively charged potassium to pass thru the cell membrane and OUT of the neuron

• major contributor to maintaining the resting potential - not the action potential

Voltage-Gated Potassium Channel:

• important for driving action potential

What is the threshold for an action potential?

• -50mV

• all or nothing sensation

• causes cascade of events to be triggered

Describe what is happening at each stage of the action potential

1) threshold is reached

• action potential begins

2) Depolarization (rising)

• voltage gated channels open

• sodium piles up on the outside of the cell, enters, via the force of diffusion

---

• As sodium comes in, the electrostatic force begins to push positively charged potassium through the potassium lead channels

• Positive charge builds up so much that voltage gated potassium channels also make potassium leave

• At peak (+40mV), sodium channels close, and potassium channels remain open

3) Repolarization

• Potassium channels stay open, continuing to leave

• This decreases the positive charge in the cell

4) Hyperpolarization

• Action Potential Undershoots the baseline (less than -70mV)

• Voltage gated Potassium channels close

5) Return to resting state

• cell goes back to -70mV

• Potassium reenters thru the leak channel

• Balancing the charge

Refractory Period — absolute vs relative

Refractory Period: until neuron recovers and settles, the neuron cannot fire another action potential

• determines upper limit of frequency, or its maximum firing range

absolute: happens immediately once the AP is initiated and ends once the membrane dips back below -50mV

• After voltage gated sodium channels close @ the peak of the action potential, they can’t be reopened for a short period of time

• therefore, it’s impossible to initiate another action potential

relative:

• after absolute refractory period ends, it lasts until the resting potential is reestablished

• sodium channels can open again so a 2nd potential can occur

• BUT the undershoot means that you need a stronger positive stimulus than normal to reach the threshold potential

• harder but NOT impossible to initiate a new action potential

Sodium Potassium Pump

• Removes Sodium and Potassium pump to maintain the ion concentration in/out of the cell

• 3 Sodium OUT, 2 Potassium IN

• works slowly, uses a lot of energy

• not important for action potentials, but maintains the ion balance of the neuron

Saltatory Conduction + Myelin Sheaths

• process of cascading action potentials along the axon maintains the signal, but it can be too slow for the speed required for communication

• special glial cells called myelin insulate the axons, leaving gaps between called nodes (which limit when the ions of AP can dissipate into the surrounding)

• AP jumps from node to node, through a process called saltatory conduction

• info can be passed without losing anything in the message

Action Potentials - Cascading Phenomenon

• action potential begins in the receptive zone where cell body and axon connect

• then it jumps down the axon, creating changes in other channels to create more APs

• AP heads towards the terminal bouton to get passed on

Neuron encoding messages

• APs are produced by given neuron identically in strength and duration

• messages are encoded in frequency and pattern

• how often the AP fires tells us how “STRONG” it is

• strong - high frequency, weak - low frequency

The Synapse

• Not a physical connection

• Synapse can maintain multiple presynaptic or post synaptic neurons

Neurotransmitter

examples: serotonin, dopamine, glutamate

• found at terminal end of presynaptic neuron

• chemicals found within intracellular packages called vesicles

• arrival of AP causes vesicles in a neuron to move toward the membrane of the presynaptic neuron

• It fuses with the neuron’s membrane and opens, spilling the molecules into the synaptic cleft

• Receptors on the post-synaptic neuron meet, continuing the process of signal transmission by a # of possible actions

Excitatory Post Synaptic Potential (EPSP)

• modify ion channels on the post-synaptic cellular membrane

• sodium channels open, allowing positive sodium ions to flow into the post-synaptic cell and moving the potential away from firing

• -50mV to fire

Temporal Summation

Temporal Summation:

• high frequency stimulation by one presynaptic neuron (over time)

• same tap dripping water into the same cup

Spatial Summation:

• simultaneous stimulation by several presynaptic neurons

• many taps dripping water in the same cup

Spatiotemporal Summation

• some EPSPs from one neuron or EPSPs from many neurons may not be sufficient to reach threshold

• blend both types to reach signal

• simultaneous, high frequency stimulation by several presynaptic neurons

Inhibitory post-synaptic potential

• ensure neurons aren’t firing uncontrollably, resulting in more noise than signal

• inhibits transmission of signal

• Cl- channels open to Cl- can enter the cell to make it negative (hyperpolarize)

• This makes the cell further from the threshold, so an AP is less likely to occur

Neural Development

1) Neurogenesis

• brain starts as a neural plate, folding into a tube

• neural plate folds at 18 days after conception, and tube is present at 28 days

• founder cells within the neural tube begin to divide symmetrically and then later asymmetrically (creating founder cells and future glial/neurons)

2) Neural Migration

• begins right after first neurons are born and continues until the last one is born

• most neurons are born before glial cells

• radio glial cells are produced before neurons → they extend from ventricular zone like scaffolding that ends at the cortex

• neurons use the radio glial cells to move from ventricular zone to cortex (inside → out)

• neurons born later have to travel further to push through the other neurons to reach their final destination

3) Neural Differentiation

• neuron takes on a specific function depending on genetics and other factors

  • some neurons are prewired to be part of the visual cortex

• BUT there is some flexibility

  • neural differentiation is influenced by input from connections with other neurons - if a neuron is connected to a visual neuron, it might process vision

  • environmental input shapes differentiation - if a neuron was needed to process binocular info and the person only has 1 eye, it wouldn’t develop properly so the neuron my be recruited for another task

4) Maturation

• when final destination is reached, neurons make connections

• neurons need neurotrophic factors from other neurons to stay alive, and the factors are limited so there is competition to make connections

• if you don’t make a connection, you get pruned (love island??)

  • synapses double from 2-4mo of age and increase until 1 yr, and then decline till death

  • increases processing efficiency and retains only useful connections

Neuroscience in Writing - how does it affect our satisfaction?

• We gave people two explanations – a good one or a bad one

• Then another two explanations were included with neuroscience terms added

• How satisfied were you with your explanation?

• People were not satisfied with the poor explanation (no neuroscience)

• But once neuroscience terms were added, everyone felt way more satisfied (even if it was bad)

• Similar to how commercials use big words

The Matrix Problem - explain the “theory”

• Robots have taken over, but we are in a simulation and we don’t know the difference

• “Brain in a Jar”

• Giving the brain action potentials so it doesn’t know the difference

• Are we all in the matrix? Is my brain in a jar and we are being fed action potentials?

• VR is going to get so realistic we won’t be able to tell the difference between real life and technology

Naïve realism

belief that we see reality as it really is: that the facts are plain for all to see; that rational people will agree with us; and that those who don't are either uninformed, lazy, irrational, or biased

Post-hoc rationalization leads to self-deception - explain cold water and healthy heart phenomenon

• participants were lied to and told that cold sensitivity was related to heart health

• So if holding the hand in the water = healthy heart, the people would hold it in longer

• But if holding the hand in the water = unhealthy heart, the people would take it out sooner

• We believe our own lies, and justify our actions

Free-Will

• Freedom of humans to make choices that are not determined by prior causes or by divine intervention

• We make choices and are responsible for those choices

Libet’s famous test of Free Will

o   Move your wrist whenever you want

o   Electrode on the wrist measures movement and an electrode on the motor cortex

o   Participant has to judge when they moved their wrist and when they decided to move their wrist 

o   The participant is ~50ms off from when they said they moved their wrist from when they actually did

o   ~200ms from when we decide to move our wrist vs when we actually move it

o   300-500ms your brain is already ramping up

Who is in charge here?

o   Criticsm -> it could be an inaccurate process, adopts the idea that we are a by-product of our brains 

Supports the idea of “free won’t”

Oligodendrocytes vs. Schwann Cells

Oligodendrocytes → found in central nervous system (brain and nervous system)

Schwann Cells → found in peripheral nervous system (all other nerves)

Describe the Neuraxis and the different anatomical directions.

Neuraxis - human nervous system axis

• it “curves”, shifting the typical axis in four-legged animals

-listed in regards to the full body, and then brain respectively

Dorsal —> toward the back (think dorsal fin) or back upper part of the brain

Ventral —> toward your stomach or lower front part of the brain

Rostral —> towards the top of your head (rooster) or upper front part of the brain

Caudal —> towards your feet or lower back part of the brain

Medial —> towards the middle of the brain

Lateral —> towards the outside of the brain

Ways to Measure Brain Activity + brief description, + pros and cons (if any)

1) Lesion studies

• tell us relationship between structure and function

• think of Phineas Gage and his frontal lobe lesion, or tests on animals where they damage a part of the animal’s brain and observe the effects

• Advantage: direct measure of a brain structure’s function

• Disadvantage: hard to selectively target particular brain regions and draw conclusions

2) Targeted Electrical Stimulation

• electrically stimulate a region of the brain and observe the result on beahviour to build a map related to function

• used by Dr. Penfield

  • patients were under anesthetics and conscious

  • use thin wire to carry a charge to stimulate the brain, fire neurons and observe the effect

3) Single-Cell Recording Techniques

• electrodes used to record ongoing electrical activity in the brain through single cell techniques

• electrode is inserted into the nervous tissue of a live animal with the tip held just slightly outside

• neural activity is recorded while stimulus is present

4) Structural and Functional Neuroimaging techniques

• used to study large scale structures and functions

• CT scan, PET Scan MRI Scan, FMRI, EEG

• Differentiate on other card.

CT Scan

• Used for structures and functions

• Computed Tomography

• x-ray slices of the brain are taken and pieced together to produce a quick and cheap picture of the brain

• helpful for diagnosing

cons:

-low resolution, hard to examine fine brain anatomy, not used in neuroscience research

MRI Scan - Magnetic Resonance Imaging

• more detailed structural image of the brain

• Powerful magnetic fields are generated which align H+ atoms in the brain

• With H+ atoms aligned, MRI can localize tissue very precisely

• super clear images but takes a while and is expensive

PET Scan - Positron Emission Tomography

• functional imaging technique

• shows how brain function relates to cognitive task

How it works:

• use radioactive tracer (glucose or oxygen) + inject into bloodstream

• tracer goes to brain and used in metabolic processes

• more active brain regions use more metabolic resources and an image is constructed

disadvantage → requires injection of radioactive tracer, invasive

FMRI - Functional Magnetic Resonance Imaging

• functional (duh) - preferred method

• produces clear brain image of its activity without a tracer

• measures the blood oxygen dependent signal and uses same principles as MRI

• measures relative use of oxygen throughout the brain and operates similar to PET

• images are striking

Disadvantages:

• oxygen used by brain spikes a few seconds later

• lots can change in seconds so FMRI isn’t ideal for precise timing

Electroencephalogram (EEG)

• Functional

• brain activity is recorded through the scalp by wearing a cap of very sensitive electrodes

• records from population of neurons to provide a rough image of brain activity

• Different stimuli can have a consistent effect on the read out and this creates a characteristic signal that acts as a marker for neural processing

on surface of brain

3 Regions of the Brain

Hindbrain, Midbrain, Forebrain (contains limbic system)

Hindbrain

• info in and out of the brain travels through the cranial nerves and spinal cord which connects here

• evolutionarily, one of the oldest brain structures, found in every vertebrate species

• regulates vital bodily functions

4 Regions of the Hindbrain

Reticular Formation: role in arousal, motivation, circadian rhythm, posture + balance

Cerebellum: facilitates coordinated movement

Medulla: responsible for breathing, digestion, heart rate, and autonomic reflexes

Pons: have a role in movement, auditory perception and emotional processing

Midbrain - what are the two major subdivisions and their functions

• two major subdivisions - tectem and tegmentum

  • important for perception, arousal, and motor control

• TECTUM:

  • superior colliculus: eye movements and visual reflexes

  • inferior colliculus: auditory integration

• TEGMENTUM

  • red nucleus: contributes to motor control

  • substantia nigra: plays a role in reward related behaviours via release of dopamine (neurotransmitter)

Forebrain - functions

• largest region of the brain

• function —> emotion, memory, perception and thought

PHAT-H

Pituitary Gland

Hypothalamus

Amygdala

Thalamus

Hippocampus

Pituitary Gland - describe two substructures

Size of chickpea, regulates and releases vital hormones, called “master gland of the universe”

Anterior pituitary: recieves signals from the brain and releases stimulating hormones to regulate important endocrine glands

Posterior pituitary: extension of hypothalamus

• releases oxytocin (helps with basic functions like lactation, uterine contractions, but also bonding and trust)

• vasopressin (blood hormone that regulates lvls of thirst by interacting with kidneys)

Hypothalamus

• directs stress response

• regulates energy metabolism by inducing feeding, digestion and metabolic rate and regulating hormonal control of mating + pregnancy lactation

• HYPE-othalamus

• 4 F’s - Fight, Flight, Feeding and Freaking

Amygdala

• receives sensory information and plays a role in decoding emotions, like threatening stimuli

• amygdala activates when stressed

• amygdala malfunctions connect to PTSD and inability to react to fear responses

Thalamus

• large structure near the centre of the brain, central relay station in the cerebral cortex

• besides olfactory (smell), axons from every sensory modality synapse to the thalamus

• thalamus processes and relays information selectively to areas of the cerebral cortex

• output from cerebellum and limbic system also pass thru thalamus

Hippocampus

• horseshoe shaped structure in the temporal lobe

• intimately involved in the process of memory and is related to your ability to hold short term memories and transfer them to long-term memory

• connected to amygdala (memories often trigger strong emotions)

• plays a role in navigation

• neurogenesis (birth of neurons) continues into adulthood

Cerebral Cortex

• rigid structure

• 4 main lobes

• folds over itself forming gyri and sulci

  • increase surface area of cortex - maximizes space for cortical processing

• evolutionarily speaking, newest part of the brain

• only about 5mm thick

Gyri vs Sulci

Gyri - ridges/bulges linked to specific mental functions

Sulci - intends that indicate where neural tissue responsible for one function ends and the next function begins

Deep sulcus is called a FISSURE and it divides major regions of the cortex responsible for distinct mental processes

Occipital Lobe

• responsible for visual processing

• contains primary visual cortex and other important visual areas

• handles basic processing of visual info and some complex visual processing

• If an individual has healthy eyes but a damaged occipital lobe, they may be blind

Temporal Lobe

• at the sides of the brain (below sylvian fissure)

• through projections from the occipital lobe, the temporal lobe contains areas responsible for processing the form and identity of visual stimuli

• location of primary auditory cortex (basic auditory processing)

• partially responsible for memory and language processing

damage results in issues with memory, auditory processing and production of speech

Partietal Lobe

• infront of occipital lobe, above sylvian fissue, terminates rostrally at the central sulcus

• connection between frontal and parietal lobe, forms the primary somatosensory cortex (which processes touch)

• involved in visual and spacial functions (location and movement of visual objects)

• contains spatial representation of the world that is involved in visual attention and guiding eye and body movements

Frontal Lobe

• most complex but least understood lobe

• along central sulcus

• frontal and parietal meet where primary motor cortex is (motor commands originate here)

• lobe also makes you human as its where decision making occurs

• If your frontal lobe is damaged, you will have dysfunctions, and if your frontal lobe is underdeveloped, you will act recklessly

Broca’s Area

• located in left frontal lobe

• area vital for speech production

• Broken Broca = broken words

• You can understand speech but can’t speak properly

Wernicke’s area

• damage to left temporal gyrus

• can’t understand speech, speak through meaningless sentences - proper grammar and rhythm

Brain lateralization - is the brain symmetrical or asymmetrical

• asymmetrical

• neuroscientists have found cases of function specialized to one side of the brain

Corpus Callosum

• carries info between 2 hemispheres

• info crosses from one hemisphere to the contralateral or opposite side of the brain thru the corpus callosum

Split Brain Syndrome Case Study

• two independent hemispheres

• once info is carried to one side of the brain, it is trapped there and unable to make it to the other side

If object is placed in the right visual field:

• you can name the object

• info travels to left side of the brain (processes language)

• but can’t comprehend that it is there spatially or feel it

left = language!

If object is placed in left visual field:

• you can feel the object

• info travels to right side of the brain (processes spatial representations of the world)

• can’t name the object because left brain can’t perceive the object

Brain is expensive to create - what does this mean?

• We have a very long childhood where we can’t really do anything independently

• probably takes around 20 years until we are independent

• human babies require a lot of investment, but then we develop into intelligent organisms (because of our big beautiful brain)

Theory of Mind

• the ability to attribute mental states (beliefs, intents, desires, emotions, knowledge) to oneself, and to others, and to understand that others have beliefs, desires, intentions and perspectives that are different from one’s own

• Essentially, ability to put ourselves in other people’s shoes

  • use box and basket comic strip

• We aren’t born with it (develops around 4 years)

• People who don’t have theory of the mind - under 4 years or autistic

How do we have empathy?

• We have motor neurons that respond to self-actions

• We also have mirror neurons that responds to the actions of ourselves and others

• If we watched someone complete a task several times, the mirror neurons would fire, and create a pathway

• Thus, if you were to perform the task on your own, the mirror neurons would be a little more established and the task would be easier

Rubber Hand Illusion and Phantom Limb Treatment - what do they prove?

Rubber Hand

• our representation of our body is not as fixed as we think

• we can connect something new (like the rubber hand) and believe that it is attached to us

Phantom Limb:

• people experience limb pain (in a limb that isn’t there) - hand often feels clenched in amputated arms

• use mirror visual feedback to treat a phantom limb that moves and feels

• if you watch your arm clench and unclench, you will believe it is moving

Both demonstrate → “Believing is Seeing”

Imposter Syndrome Case Study

• man got into a car accident and went into a coma

• family visited (specifically dad), but the patient said it wasn’t his father in the room even though it looked like him

• it had a connection to visual recognition

  • when we recognize faces, it has a corresponding emotional significance

  • Neurons in Fusiform Face Gyrus respond to faces and the amygdala accesses the emotional significance (areas communicate so faces trigger emotions)

  • Called Capgras delusion

  • brain creates a running narrative to explain - “if i don’t love this man, my dad must have a doppelganger”

Hemi Spatial Neglect

• ignoring the left half of the world because there is damage in yoru right parietal lobe

• only shaving right half of face, eat off right side of plate, etc.

• not a visual issue, your brain is just not paying attention

What happens if you damage your left side of your brain vs on the right?

Left:

• can’t see on right side, but other hemisphere attends to both so you are okay

Right

• damage means you lose both sides, and only have attention on right side (left brain remains)