PSYCH 104: chapter 3 and 4

neuron

basic building blocks of the nervous system - send signals to each other and this signalling is what allows us to perceive, think and feel emotions

axon

conducts electrical impulses away from the cell body to other neurons, muscles or glands

soma/cell body

contains the structures needed to keep the neuron alive

dendrites

receive messages from neighbouring neurons and send them on to the cell body - branchlike fibres at the end of the cell body

myelin sheath

a fatty insulation layer that covers the axon of some neurons and helps speed nerve impulses

resting potential

neuron is at -70 millivolts, filled with negatively charged ions while the positively charged sodium ions are mostly outside of the neuron

threshold

when an impulse passes the threshold level of -55mV a signal is sent

action potential

all of the sodium channels open up and positive sodium ions come into the cell, the neuron becomes positively charged and that positive charge runs up the axon where it causes neurotransmitters to be sent across the synapse

refractory period

recovery period where until neuron is back at its resting potential another signal cannot be sent

all or none law

neuron either fires or doesn’t, there is no such thing as a strong or weak signal

synapse

space between the dendrite of one neuron and the terminal branches of another

neurotransmitters

chemicals that carry messages across the synapse to either excite or inhibit the activity of the next cell

excitatory neurotransmitters

increase the chance that the next neuron will have an action potential

inhibitory neurotransmitters

decrease the chance that the next neuron will have an action potential

reuptake

if a neurotransmitter does not bind to a receptor, the axon that they came from takes them back and recycles them

glutamate

main excitatory - involved in the control of all behaviours, especially learning and memory

GABA

inhibitory transmitter - involved in controlling all behaviours, especially anxiety and motor control - sleep and released when you consume alcohol - huntington’s disease

acetylcholine

excitatory at synapses involved in muscular movement and memory - alzheimers

norepinephrine

excitatory and inhibitory - involved in neural circuits controlling learning, memory, wakefulness, and eating - chemically similar to adrenaline, involved in alertness and arousal

serotonin

inhibitory - involved in sleep, mood, eating, and arousal - depression is thought to be caused by low serotonin

dopamine

inhibitory or excitatory - involved in voluntary movement and the experience of pleasure and reward - parkinsons, depression, schizophrenia

endorphins

inhibit transmission of pain impulses

sensory neurons

carry input messages from the sense organs to the spinal cord and brain

motor neurons

transmit output messages from the brain and spinal cord to the body’s muscles and organs

interneurons

perform connective and associative functions within the nervous system - process info and form plan - make up the vast majority

central nervous system

all of the neurons in the brain and spinal cord

peripheral nervous system

all of the neurons that connect the central nervous system with the muscles, glands and sensory neurons - nerves and bundles of neurons

somatic nervous sytem

controls movement - motor neurons send signals to this part of the system - voluntary

autonomic nervous system

operates outside of conscious and voluntary control - automatic

sympathetic nervous system

fight or flight response - no digestion, increased heart rate and breathing rate, dilated eyes - activated when under situations of threat

parasympathetic nervous system

rest and digest - heal wounds, digest food, fight off disease - default system

reflex

movement is initiated without the brain - spinal cord initiates a quick response before brain can process the pain from the stimulus

transcranial magnetic stimulation

uses a magnetic coil placed in different parts of the brain to turn off or interfere with those areas

eeg

video technique that uses a cap with electrodes that measure electrical activity at the scalp - excellent time precision, poor spatial precision

cat/ct scan

picture technique that uses a x-ray machine for your brain

mri

picture technique that uses a giant magnet that activates different molecules in the brain to measure the amount of activation in the different parts of the brain

fmri

video technique that measures blood flow in the brain with radioactivity - poor time precision, good spatial information

pet scan

video technique that injects radioactive dye to measure blood flow in the brain

hindbrain

cerebellum and brain stem (pons and medulla)

medulla

regulates vital functions like breathing and circulation

pons

serves as a bridge carrying nerve impulses between higher and lower levels of the nervous system - regulates sleep and arousal - contains motor neurons that control face and neck movement

cerebellum

muscular movement coordination - ensures that habitual/well practiced bodily movements are coordinated and well executed

midbrain

very basic visual and auditory processing and guides automatic reactions

reticular formation

either turns arousal up to make you conscious and awake or down to make you sleep like a dimmer switch - group of fibres that carries information related to sleep and arousal through the brain stem

forebrain

consists of two large cerebral hemispheres, left and right, that wrap around the brain stem

cerebral cortex

outside, bumpy looking layer - split into 4 lobes

occipital lobe

vision processing

parietal lobe

sensory strip, spatial processing and tasks, later stage of visual processing (figuring out where an object is)

sensory cortex

responsible for touch perception

temporal lobe

hearing and later stage of visual processing (figuring out what an object is)

wernicke’s area

involved in language comprehension (understanding what someone else is saying)

frontal lobe

long term planning, rationality, self control

motor cortex

initiates voluntary movement

broca’s area

involved in language production (speaking and writing)

phineas gage

rod went through his frontal lobe, personality changed - lost impulse control

limbic system

deeper structures involved in emotion and instict

thalamus

takes signals from all the senses (except smell) and directs them to the cortex

basal ganglia

helps to make sure that motor movement is well executed - voluntary and conscious movement

hypothalamus

the boss of the hormone system - involved in the 4 f’s of survival (feeding, fleeing, fighting and sexual functioning)

henry molaison

had his hippocampus removed and could not make new long-term memories

hippocampus

important for the creation of new long term memories

amygdala

important for emotional experience, especially fear and aggression

nucleus accumbens

important for pleasurable/rewarding experience - sends dopamine throughout the brain

hemispheric lateralization

difference between left and right hemispheres

left hemisphere

gets information from the right visual field, controls the right side of the body, and controls language

right hemisphere

gets information from the left visual field, controls the left side of the body

corpus callosum

allows the two hemispheres to communicate

split brain patients

to treat epilepsy we used to cut the corpus callosum - prevents the seizure from travelling to the other side of the brain - patients seem to have two separate spheres of consciousness, if you show something to the right (non-talking) hemisphere they cannot talk about it

neural plasiticity

the brains ability to adapt in response to damage or change - very high in young people

dna

chemical structure inside your cells that contains the instructions for building your body

gene

a segment of dna that codes for a trait

chromosome

a larger segment of dna (defined in terms of how tightly coiled it is)

genotype

all of an organism’s dna

phenotype

all of an organism’s traits

dominant vs recessive genes

if a dominant and recessive gene disagree, the dominant gene wins - only need one dominant trait for it to be expressed

epigenetics

when the environment causes a change in gene expression that gets passed on, without changing the actual genes/dna code

mutation

actual dna code is changed

recombinant dna procedures

researchers use specific enzymes to cut the long threadlike molecules of genetic dna into pieces, combine them with dna from another organism and insert the new strands into a host organism

knockout procedure

alter a specific gene in a way that prevents it from carrying out its normal function

heritability

our dna - one way to measure the contribution of genes, how similar are identical twins raised apart (share genes, not environment)

shared environment

the environment that is shared by siblings - one way to measure the contribution of the shared environment, how similar are adoptive siblings (share environment, not genes)

non-shared environment

the environment that is not shared by siblings - one way to measure the contribution of the non-shared environment, how different are identical twins raised together (share their genes and environment)

adoption studies

a person who was adopted early in life is compared on some characteristic both with the biological parents (share genes) and the adoptive parents (share environment)

twin studies

compares behavioural similarity in samples of identical and fraternal twins - if the identical twins are more similar than the fraternal, a genetic factor is involved

monozygotic twins

identical - develop from the same fertilized egg so they share virtually all of their genes

dizygotic twins

fraternal - develop from two fertilized eggs so they share 50% of their genetic endowment

reaction range

the range of possibilities that the genetic code allows for a genetically influenced trait - the environment influences where on that range you will fall

laws of behaviour genetics

everything is heritable (40-50%), the effect of the shared environment is smaller than genes (0-20%), the effect of the non-shared environment is large (40-50%), everything is polygenic (caused by many genes)

caveats about heritability

how much genetics explains variation in a trait, estimates are about differences between individuals within any defined group, can change depending on the environment

big five personality traits

openness to experience (trying new things, open mind), conscientiousness (hard working, detail orientation), extraversion (outgoing, positivity), agreeableness (politeness, niceness), neuroticism (sensitivity to negative emotions) - 40-50% heritable

behaviour psychology

about human differences

evolutionary psychology

about human universals - the ways in which we are the same because of our evolutionary past

basics of evolution

inheritance of traits (traits get passed on via genes), variation in traits (traits are different bc of random mutation), differences in reproductive success (some traits get passed on more than others) - results in natural selection

natural selection

some genetically caused traits will increase in frequency over time because they are more suited to the environment

adaptation

a trait that was selected by natural selection because it increased the probability of survival and reproduction - umbilical cord

byproduct

a side effect of an adaptation that does not itself have survival value - belly button

domain general adaptation

a capacity that is designed to deal with many different types of incoming information - reward and punishment

domain specific adaptation

a capacity that is designed to deal with one particular type of incoming information - color vision

proximate explanation

explaining something in terms of the immediate physiology and environment

ultimate explanation

explaining something in terms of evolution