NEUR1020 - Module Quiz 1

what is the scientific method

• the iterative means by which scientific knowledge is amassed, tested and refined

• it describes the relationship between three components:

  1. observation (data)

  2. explanation (theory)

  3. prediction (hypothesis)

what are the two properties a theory must have to be considered scientific

1. they must make testable predictions that can be evaluated against data

2. the predications must allow for the theory to be shown to be false

what happens when a theory is confirmed by observation

• then it is provisionally accepted and another hypothesis is tested

• theoretical adjustments can be made to see if the theory can be brought in accord with disconfirming results

what is a science

any discipline that makes used of the scientific method.

what are the five major paradigms in psychology

1. psychodynamic

2. humanist

3. behavioural

4. cognitive

5. biological

what is a paradigm

• a framework for understanding and investigating phenomena within a discipline

• they outline fundamental assumptions that are made within a discipline, providing a general perspective on theory and research

• colours how one views human pyschology

what is an example of a medicinal paradigm

• the miasma theory → the germ theory

when do paradigms change

• when they prove to be insufficient to explain key phenomena within a discipline

what is the behaviourist paradigm

• the external environment was the determinant of both observable and unobservable behaviours

• rejects that idea that mind and mental events play any causal roles and are thus, behaviours caused by the environment

• BF Skinner first introduced this idea.

what is the cognitive paradigm

• places mental events and representations at the centre of psychology → mental events could be studied as causal determinants of behaviour

• seeks to understand the processes that transform stimuli into behaviours

• what is the functional relationship between different kinds of cognitive processes

what is the biological paradigm

• seeks to explain cognition and behaviour in terms of biological processes (ie. patterns of neural activity)

• uses approaches such as FMRI and EEG

• does not focus on exclusively the abstract relationships between cognitive processes

what is introspection

• the process of looking inward and reporting on the machinations of one’s own mind.

• this involves observing and reporting without embellishment or influence of prior knowledge

• results are more variable with more complex processes

what are case studies (and importance)

• biological information about a single individual, obtained retrospectively, and often through interview

• this can provide existence proofs about phenomena and hint at causal relationships

• an example is phineas gage

what are surveys and self-reports (and importance)

• a methodology that combines elements of introspection and case studies

• the structured set of questions retains an interview-like quality that can quantify insights achieved via introspection

what are naturalistic observations (and importance)

• where participants do not respond to specific questions but instead are simply observed performing a certain task or activity

• is an objective method of assessing behaviour that is unaffected by potential self-report biases

• can identify baseline sets of behaviour that can later be targets for future research.

what is correlation design

• seeks to quantify the statistical strength of the relationship between two variables

• they are able to identify associations between variables but cannot be used to make claims about causality

what is experimental design

• specifically set up to enable causal inference

• randomly allocates people to groups then adds an experimental manipulation that introduces a single systematic difference

• if there is a difference on the DV this can be attributed to the manipulation of the IV

what are the three main divisions of the brain

1. cerebrum (cerebral hemisphere and forebrain)

2. cerebellum (hind brain)

3. brain stem

what is the cerebral cortex

• the outermost surface layer of the cerebrum = grey matter

• contains most of the cell bodies of the neurons of the brain

what is white matter

• underneath the grey matter and is all the wiring (ie. axons of the neurons)

why is the brain intricately folded

• to allow a lot of cortex (= more neurons) and maximises the surface area of the brain relative to the volume of the brain

what are the primary areas of the brain

• divided amongst the four lobes of the brain

• usually the first site of input into the brain from our senses and the last stage of output

what is the function of the frontal lobe

• executive functions:

  1. reasoning, planning, problem solving

  2. inhibitory control

  3. working memory

• motor functions:

  1. premotor cortex-motor planning

  2. primary motor cortex execution

• speech production

function of the parietal lobe

• primary somatosensory cortex:

  1. perception of touch

• sense of space and locations

  1. gives sense of stable world around us relative to our body position

• spatial attention

  1. directing attention and eye movements to explore visual world

• linking vision to action

  1. represents spatial location of objects around us for guiding actions

function of occipital lobe

• primary visual cortex (VI):

  1. all visual perception

• higher visual areas:

  1. different regions process, shape, colour, orientation, and movement

in regard to the parietal lobe - where is the occipital lobe located

• posterior part of the brain, inferior to the parietal lobe

function of the temporal lobe

• primary auditory cortex:

  1. perception of sound

• language comprehension

• medial temporal lobe:

  1. limbic system → amygdala and hippocampus

function of the amygdala

• fear and arousal:

  1. responds to threat/danger

  2. fear (learning phobias)

function of the hippocampus

• learning and memory:

  1. forming new episodic memories

  2. damage causes anterograde amnesia

what is the function of the corpus callosum

• neurons connections between the left and right hemispheres

• allows brain communication between hemispheres

what was the first case studies used to map brain function

• phineas gage

• identified the important role of the frontal lobe for executive control of behaviour

what did broca identify

• the left frontal lobe as the area for speech production

what did Wernicke identify

• suggested the left posterior temporal lobe was responsible for language comprehension

what is a major technique used to map function in the brain

• electrical stimulation used during surgery

what is the brainstem and function

• the part of the brain that connects between the cerebral hemispheres and the spinal cord

• the brainstem drives the autonomic nervous system

what is the ANS responsible for

1. heart rate, respiration, sweating

2. stress, arousal, fight or flight

• it is involuntary

what are the two divisions of the ANS

1. sympathetic nervous system → increases heart rate, respiration, perspiration, pupils dilate

2. parasympathetic nervous system → lowers heart rate, respiration, and opposes SNS

what is the medulla

• the main part of the brain that drives the ANS

what is persistent vegetative state (coma)

• caused by severe damage to upper brain (hemispheres and cortex)

• if brainstem is not damaged then ANS functions can remain

• patients have no conscious awareness

what is amyotrophic lateral sclerosis (ALS)

• a motor neuron disease where the cerebrum and brainstem are intact but disconnected from spinal cord

• patients may be fully conscious and aware, but totally unresponsive

where is the cerebellum located

• lies at the posterior inferior part of the brain

what is the cerebellum responsible for

1. sense of balance and coordination of complex movement

2. motor learning fine adjustment of movement based on feedback

what is the primary motor cortex

• located higher in the brain → activity in the primary motor cortex leads to movement (muscle contraction).

what is the primary sensory cortext

• activity leads to sensation

why can you not tickle yourself

• the brain automatically links sensory events and own actions to infer causally. It gives you a sense that your action caused that event

• the brain computes the difference between planned action and feedback during performed action.

what are neurons

individual cells that mediate the complex functions of the brain

how do neural signals work

• only go in one direction from input (dendrites) to signals that are propagated along the axon and output through axon terminals across synapses.

explain the cell body

• common to all cells

• contains nucleus and all structures necessary for cell functioning (DNA)

explain dendrites

• unique to neurons

• receives signals → input zone

• many per neuron, receives input from many other neurons

explain the axon

• unique to neurons

• sends signal → output from axon hillock at cell body to axon terminals

• one per neuron → only one axon for output

• wrapped in myelin for efficient transmission of signals along the axon

explain axon terminals

• terminal boutouns/buttons

• form synapses with other neurons

• secrete neurotransmitters to send signals across synapses to other neurons

what are the glial cells

• brain contains neurons and glial cells

• glial cells are supporting cells for neurons

• there are three types of glial cells

function of oligodendrocytes

• produce the myeline sheath that wraps around axons

function of astrocytes

• supply nutrients from blood to neurons and maintain a blood brain barrier

function of microglia

• brain’s immune system and cleans up foreign/toxic substance

function of synapses

• join axon terminals of one neuron to dendrites of another neuron for transmission signals between neurons

• neural signals go one way

pre-synaptic vs post synaptic

• pre synaptic (before the synapse) → from cell body to axon terminals

• post synaptic (after the synapse) → from dendrite to cell body

what is action potential

• communication in the brain and long the nerve pathways of the body is through electrical impulses called action potentials that travel along the axons of neurons

• relies on the flow of ions or salts in water that sits around the neuron

• always a fixed sized → either on or off, signal or no signal (not large or small)

extracellular vs intracellular fluid

• extracellular fluid is water that surrounds the cells (outside cell)

• intracellular fluid or cytoplasm is when water fills the cells (inside the cells)

• the cell membrane forms a barrier between extracellular and intracellular fluid

what are the main ions in the water of cells

• main ions are sodium and potassium → there are different concentrations of these ions outside and inside the cell, across the cell membrane

• there are more positive ions outside the cell and fewer ions inside the cell.

• this gives a different electrical charge across cell membrane

membrane potential

• difference in the electrical charge (voltage) between inside and outside the cell across the cell membrane

resting potential

at rest (not during an action potential) more positive ions outside than inside the cell gives an overall negative potential (voltage) inside the compared with outside the cell.

what is the difference in electrical charge at rest

-70mV

what are ion channels

• located in the cell membrane wall and open/close to pass or block movement of ions across cell membrane

• ions move between intra and extracellular fluid

• movement of ions changes electrical potential

what is the sodium potassium pump

• actively pumps sodium and potassium across cell membrane

• overall pumps positive charge out of cell (3 sodiums for every 2 potassiums in)

• positive charge will naturally move towards negative area

• maintains negative resting potential

• uses energy

what is the voltage dependent ion channel

• closed at resting potential

• opens when membrane potential reaches threshold voltage (positive ions can flow from outside into the cell)

• causes depolarisation of cell (as voltage less negative = closer to zero)

what is the potassium voltage gated channel

• opens up at the peak of action potential.

• allows potassium to flow out of the cell

• causes repolarisation

what triggers action potential

• input from other neurons increases membrane potential. If voltage exceeds threshold, it triggers action potential

depolarisation

• membrane potential goes back to zero

• depolarisation is fast

repolarisation

• membrane potential goes back to -70mV

what is the undershoot/refractory period

• more difficult for another action potential to occur.

• further to threshold to trigger another action potential

• prevents action potential going backwards

what determines the strength of neuron signals

• the rate of the repeated action potentials

where does action potential start

• begins axon hillock as it has the lowest threshold to trigger action potential

how are neuron signals sent

• depolarisation of axon terminal (action potential) triggers release of neurotransmitters

• neurotransmitters act on receptor on post-synaptic neuron to open ion channels and pass signalsd

• this causes chemical signals from neuron to neuron

what are neurotransmitters

• chemical messenger

• released from pre-synaptic terminal

• acts on post-synaptic receptors

what are synaptic vesicles

• stores neurotransmitter in pre-synaptic terminal

• neurotransmitter taken back into pre-synaptic terminal is re packaged into vesicles

what are neurotransmitter receptors

• gates on post-synaptic side

• activates receptor to open ion channels on post-synaptic neuron

what is the lock and key model (in reference to neurotransmitters)

• each receptor only binds to a specific type of neurotransmitter

• neurotransmitters only activate their specific type of receptor

• important for drug effects

what is the re-uptake pump

• clears neurotransmitter from synaptic cleft back into pre-synaptic terminal

what do enzymes do for neurotransmitters

• break down neurotransmitter in synaptic cleft.

• both enzymes and re-uptake pump stop neurotransmitter signalling to post-synaptic neuron

what is the ligand gated channel

• when different neurotransmitters bind to and open the ion channel (letting through sodium, potassium and chlorine) to change membrane potential in different ways

what are the two signals activated by neurotransmitters (receptor channels)

1. excitatory

2. inhibitory

inhibitory signal

• receptor opens channels that cause hyper-polarisation

• further from threshold for action potential

excitatory

• receptor opens channels that cause depolarisation.

• closer to threshold for action potential

what is the graded potential

• excitatory and inhibitory inputs combine together (changes membrane potential on post-synaptic cell)

• graded potential on post synaptic cell depends on strength of synapse connection:

  1. strong connection causes large change in membrane potential

  2. weak connection causes small change

what is input trigger

• membrane potential at axon hillock depends on sum and timing of inputs through dendrites

• if enough excitatory inputs occur together close enough in time, membrane potential will exceed level for action potential

brain lesion methodology

• explains normal brain function by examining what changes when part of the brain is damaged (ie. stroke or brain injury)

• based on the assumptions that whatever changes in behaviour/cognition must rely on that part of the brain

what is single neuron recording

• place a thin electrode into an animal’s brain (ie. rat)

• record action potentials firing from a single neuron

• measure what that neuron encodes or detects

what is the benefit of use single neuron recording

• most accurate for localisation and timing of brain activity

• been studied extensively in vision (visual cortex) → Hubel and Wiesel used this technique to find the first recordings from visual cortex neurons in cats

• also quite commonly used in the motor system → decoding movement plant/intentions from neural activity (maybe a way of developing neural prosthetics)

what are some problems with single neuron recording

• highly invasive (electrodes directly into brain)

• animals only

what is EEG

• summed activity from action potentials of neurons in the cortex cause electrical activity change in the scalp

• measures voltage changes from electrodes place on the scalp

• brain activity in EEG shows constant oscillations

• frequencies of oscillations change with alertness and sleep

what are the clinical uses of EEG

• detecting stages of sleep

• monitoring for epileptic seizures

what are the important frequency bands of EEG

1. alpha activity (8-12 Hz)

2. delta activity (1-3 Hz) → shows deep sleep as slow waves

what is ERP

• brain activity related to a specific event or stimulus

• average together >100 trials of EEG in response to the stimulus

• peaks represents different stages of processing of the stimulus

• can show precise time of information processing in the brain

what are the clinical uses of ERP

• detecting deafness in babies (eg. auditory event related potentials)

what are some problems with ERP

1. difficult to localise activity to specific brain areas

2. poor spatial resolution

PET scans

• uses radioactive substances injected into bloodstream.

• used now to map neurotransmitters or receptors in the brain

what is the difference between MRI and fMRI

MRI → studies brain anatomy

fMRI → studies brain function

fMRI

• detects change in blood oxygen level (BOLD signal)

• active neurons use oxygen → change in blood oxygen level = change in brain activity

• a good localisation of brain activity

what are some problems with fMRI

• indirect measurement of brain

• very expensive