Neurons and neurotransmitters Flashcards
What is a neuron?
Specialised nerve cell
What are the five main parts of a neuron?
Dendrites Cell body (soma) Axon nucleus Synapses (presynaptic and postsynaptic)
explain resting membrane potential (RMP) and what is the RMP?
RMP means there’s a difference in electrical potential between the inside and outside of the cell and the cell is at RMP when not transmitting information
-70MV
small input into the dendrites =
large input into the dendrites =
small change in membrane potential
Large change in membrane potential
Where does Graded potential occur and what is it?
the dendrites and it occurs when there is a change in electrical potential as a response to input. The strength of the change of comparative to the input into the cell
What is temporal summation and spatial summation?
Temporal summation is when there is two lots of inout, one after another. The first input creates a small graded potential and as the second input comes in it adds on creating summation of inputs. resulting in a larger graded potential
What is the threshold of ion channels?
the graded potential has to meet a certain level of depolarisation for the euro to fire an action potential
Difference between grade potential and action potential
The difference is that action potential is triggered by membrane depolarisation at the threshold and graded potential is responsible for the initial membrane depolarisation of the threshold.
What are synapses and where are they located?
connections between neurons where the axon terminal sends messaged to other neurons and they are located on the dendrite or on the cell body
What is a neurotransmitter?
Neurotransmitters is a chemical that transmits information across synapses
How do drugs change synthesis?
Drugs reduce the amount of neurotransmitters that synthesis, which decreases the amount of neurotransmitters available when they are released across the cleft
How do drugs change storage?
Drugs may cause vesicles to leak, decreasing the strength of the message as there will be less neurotransmitters in the vesicle
How do drugs change release?
They increase or decrease the amount of neurotransmitters being released over the threshold.
How do drugs effect binding?
They block receptors so when neurotransmitters are released across the cleft they won’t be able to bind with receptors due to blockage. Graded potential won’t occur as strongly
How do drugs change reuptake ?
Enhances messages across the synapses because neurotransmitters are going to sit round in the cleft for longer because the reuptake processes been slowed down
How to drugs effect a person?
change perception or behaviour and cognitions
what is pareidolia?
The tendency to perceive a specific image in a visual pattern
what’s the difference between the central nervous system and peripheral nervous system?
central nervous system - brain and spine
peripheral - everything else including nerves which send out information and receive it to send back to the nervous system
What are the four lobes of the brain ?
Frontal lobe, temporal lobe, parietal lobe and occipital lobe
Where on your head is the frontal lobe located?
front of head
what is an axon
is where electrical impulses from the neuron travel away to be received by other neurons.
what is an axon hillock?
the region where the plasma membrane generates nerve impulses
where does action potential occur?
Axon terminal
What is dendrites
part of the nerve cell that receives input
how do axon terminals work?
they are specialised to release the neurotransmitters of the presynaptic cell
what is a vesicle ?
area in axon that holds neurotransmitters
what is the process of neurotransmission?
action potential travels down axon to axon terminal, action potential will cause a change in electrical potential. This causes vesicles to be used out of the membrane to release neurotransmitters out of the membrane into the cleft. Float around in the cleft until binding occurs. Binding causes graded potential. The reuptake occurs where remaining neurotransmitters in the cleft are taken back up by the terminal.
What is a presynaptic neuron?
that fires the neurotransmitter as a result of an action potential entering its axon terminal
What occurs in the reuptake process?
Neurotransmitters move away from the cleft and are moved back into the axon terminal where they either metabolise or converted into a form that can be used to generate new neurotransmitters
What is a post synaptic neuron?
synapses that receives the neurotransmitter after it has crossed the synapse
What is the neurotransmitter acetylcholine?
acetylcholines role in the centrals neverous system is memory
what happens if you have decreased acetylcholine and what does it cause ?
It will cause impaired memory
why is acetylcholine important?
It is important because in order for movement to occur at the cholinergic synapse the neurotransmitter acetylcholine is used. acetylcholine has a role in causing movement, speaking, etc. If synapses dent work properly and acetylcholine isn’t being used correctly then you may be paralysed.
what causes Parkinson’s disease and schizophrenia?
Parkinsons is a decrease in dopamine and schizophrenia is an increase.
Dopamine and its relation to drugs of abuse
All drugs of abuse cause activation of the dopamine circuits increasing the release of dopamine
What is intrecal self stimulation (icss) ?
It is an experiment where probes are out into the brain to activate dopamine pathways (with activates neurons that use dopamine and a neurotransmitter)
What experiment was conducted for intrecal self stimulation?
One on rats where they had to press the bar to cause the release of dopamine. They found that the mice always pressed the button constantly. If given the option to choose food after been starved or the button releasing dopamine they choose the dopamine release.
What are the three main parts of the brain activated during intrecal self stimulation (icss)?
prefrontal cortex
Nucleus accumbens (where dopamine is released)
ventral Tegmental Area (VTA) - contanins neuros and cells bodies
what is the Nucleus accumbens?
deep part of the brain where dopamine is released
what is the ventral Tegmental Area (VTA)
part of brain that contanins neurons and cells bodies
What does dopamine do?
Had a role in the reward system to create pleasurable feeling and indulge in pulsive behaviour
How does the reward system work?
When you have drugs of abuse, humour etc it activateds the VTA and Nucleus accumbens to cause feelings of reward
how does deeb brain stimulation reduce depression?
It improves mood, and relieves feelings of depression
what are the main factors on the outside of the cell?
positive ions, sodium
what are the main factors on the inside of the cell?
anions and negative ions
What generates membrane potential ?
When ions are being pushed from one side of the cells to another through the ion channels specifically when potassium leaks from the inside of the cell to the outside via potassium channels. This generates a negative charge in the inside of the membrane vs the outside
What are ion channels?
a group of proteins that form a channel that creates a cell membrane. The ion channels allows the passage of ions between the extracellular environment and the cytoplasm of the cell.
What happens when the membrane potential depolarises?
it is caused by a rapid rise in membrane potential when sodium channels are opened in the cellular membrane. This results in a large influx of sodium ions into the cell. This causes the negative charge in the cell to be cancelled out by positive sodium ions
how do neurons transmit information within the neural structure?
through pulse activity that is produced by changes in the membrane potential.
How does pulse activity travel through the body?
Pulsive activity travels from dentries through the cell body along the axon as an action potential
how many synapses are there in the human brain?
Over 80 million
what is an agonist drug?
A drug that binds to the receptor on the cell to trigger a Response. It does this by acting as a naturally occurring substance
what is an indirect agonist drug?
Drug that enhances the release or action of an endengous neurotransmitter. This may happen due to an increase in synthesis. Overall it creates a grater response
what is an action potential?
Electrical impulses that send signals around the body.
What occurs during an action potential?
A temporary shift from positive to negative occurs in the neurons membrane potential which is caused by ions flowing in and-out of the cell
what are examples of reflexes
blinking , swallowing, pupil dilation, sneezing
what are the three types of reflexes
stereotypes, subconscious and unlearned
what is a reflex?
a simple automatic reposes to a stimulus
what do alpha motor neurons do?
generates movement as it causes muscle fibres to contract and allows larger muscles to generate force
What is the monosynaptic stretch reflex?
It occurs when a muscles stretches. the function of the reflex it allow muscles to maintain posture
what is inhibitory input?
Instead of the neurons depolarising the cell hyper polarises pushing the cell away from the threshold
What is synaptic communication?
When the message that transmitted pars synapses in exhibitory which increases the likelihood of the cell firing
what is the purpose of inhibitory input
so that when muscles are working together it ensures only on contracts at a time to ensure movement
What is ICSS
Intracranial self stimulation
What does ICSS do?
Activates dopaminergic pathways including the nucleus of accumbean and VTA
What does ICSS on animals show
Shows that pleasurable effects where produced
what are the three parts of the brain activated during ICSS
nucleus accumbent
VTA
prefrontal cortex
What activates the human reward system?
reinforcers such as food, sex, money, drugs of absue
What is Parkinson’s caused by ?
A lack of dopamine
What is schizophrenia caused by?
an increase in dopamine
What happens when you increase the dopamine dose of someone with Parkinson’s?
Will have reverse effects causing them to develop schizophrenic symptoms
How are drugs of abuse and dopamine related?
Because drugs such as coke increase dopamine levels in the brain
what is Broca s aphasia and where does it occur?
When your unable to say what your thinking . occurs in temporal lobe
What is divergent thinking?
when you create multiple ideas
what’s the 7 + 2 experiment?
that the number of objects an average human can hold in working memory is 7 ± 2.
who did the 7 + 2 experiment?
Miller
What did peter tripp (1959) experience after going 201 hours without sleep?
- Mild psychosis
- Hallucinations
- Paranoia
What did randy Gardener experience after going 264 hours without sleep?
- Very little change
- Mild impairments in social behaviour
What are three sleeping tests?
EEG = electroencephalogram – brain activity EOG = electrooculogram – eye movement EMG = electromyogram – muscle tone
What did Peter trip and randy grammar experiment?
how lack of sleep effects the body
Do we dream more in REM sleep of SWS?
REM. 80% of people in REM sleep remember dreaming compared to only 7% of people in slow wave sleep remember dreaming
- ———— memory is increased by SWS and
- ————memory is increased by rem….
Declarative memory is increased by SWS and
Procedural memory is increased by REM
In wade et al’s (2002) memory distortion test what event were participants doing in the photograph?
-hot air ballon ride
What is the wake maintenance zone and how long does it last?
it is the evening peak of alertness and it occurs from 7-9pm
how long is the body clock cycle?
24.5-25 hours
what is semantic memory?
memory of meaning, understanding and concept based genral knowledge
What was Milners skill task 1965?
mirror drawing task
Why do we forget?
Trace decay – cessation of neural firing (STM)
Weakening synapses
Forgetting due to interference
What speeds were the cars said to be going when participants where asked about smashed compared to asked about when hit?
- 41mph – smashed ‘
- 34mph – hit
What is the best form of rehearsal to encode ideas into LTM?
elaborative rehearsal
What is the method of Loci?
-Linking an idea or objects to a common routine in order ti retrace steps and discover the info again
What did Peterson and Petersons study find?
- Preventing rehearsal produces rapid forgetting
- That memory’s decay within 20seconfs if rehearsal is prevented
what is chunking?
splitting information into groups so it’s easier to dealt with
What does Atkinson and Shiffrin’s 1971 model show
- primacy and recency effects
- model of memory
what increases synaptic strength?
- Increase in neurotransmitter release
- Increase in postsynaptic response
- Increase in synaptic connections between neurons
What percentage of synapses in increases in neurons by using an enriched environment ?
-15%
What is the cognitive memory hypothesis?
-Enrichment appears to aid in preventing age related cognitive decline
What are the three steps of memory?
- Encoding ‘
- storage
- Retrieval
Which test was ebbinghouse (1850-1909) involved in ?
syllable memory
What is the difference between agonist and antagonist?
- Agonist – increases effects
- Antagonist – reduces effects
What is the human reward system useful for?
-survival of species
how many alpha neurons do we have?
400,000
what are some positive effects of schizophrenia?
- Delusions
- Hallucinations
- Disorganisation
What are some negative effects of schizophrenic?
poverty of speech
what are some neurotransmitters In the brain?
- Acetylcholine
- Dopamine
- Noradrenaline
- Glutamate
- Serotonin
What is the key chemical that can stop AP?
- Tetrodotoxin
what is the PR3 gene looking at ?
Circadian rhythm’s
What does noradrenaline do?
- It plays an important role in your body’s “fight-or-flight” response
- Increases alternes, arousal and attention
Whats curare?
-Curare and related compounds exert their effects by blocking the activity of acetylcholine at neuromuscular junctions, resulting in paralysis.
What does the Bransford and Johnson study 1972 show? - comprehension
-Elaborative encoding improves compression and memory
What’s phase advancing and chase delaying?’
- Phase advance = shifting the time you go to sleep and time you wake up to earlier in the sleep wake cycle. E.g moving bed time from 10-8 and wake up time from 8-6
- Phase delay = shifting the time you go to sleep and time you wake up to later in the sleep cycle. E.g changing sleep time from 8-10 and wake up time from 8-10
How much time is spent in rem sleep?
- Babies – 50%
- Adults 20-25%
What curare blocks the action of a neurotransmitter by occupying its receptors sites?
-An antagonist
Failing the knee jerk test indicates?
-A problem in the neural pathways in the spinal cord
What is the cerebellum?
- Located at the back of the brain underlying occipital lobe and temporal lobes
- It is important for making postural adjustments to maintain balance
What’s the amygdala ?
- Cluster of cells located near the base of the brain
- Helps regulate and define emotions
What’s the suprachiasmatic nucleus?
- Bilateral structure located in the anterior part of the hypothalamus
- It is the pacemaker of circadian timing, regulating circadian rhythms in the body
Melanopsins photoreceptors
-Respond to Prescence of light by transmitting signals to the SCN
What’s impaired remote memory?
- Occurs when you have retrograde amnesia
- Do a remote memory test to test if you remember things prior to accident
What is context dependant amnesia?
-Forgetting can occur when the environment during recall is different from the environment you were in when you were learning.
What is consolidation?
-Hypothetical process by which memories are transferred from liable short term storage to more robust long term storage
What’s declarative memory?
- Processing of names, dates, places, facts and events.
- Specialised for fast processing and learning
What’s structural memory?
-Structural encoding focuses on what words look like. For instance lower or uppercase words
What’s procedural/implicit memory?
-Long term memory related to performance of different skills and actions such as cooking, riding a bike etc
What’s proactive and retroactive memory?
Proactive – old memory’s interfere with new memories
Retroactive – new memories interfere with recall of old memories
Knowledge that a bird fly’s is help in what part of memory?
semantic memory
Deep processing of the stimuli describe by craik and Tulving would require you to?
-Determine whether flower made sense in a sentence about gardens
Elaboration is ?
-Linking the stimulus to other information at the time of encoding
Godden and Baddeley’s (1875) showed?
- That context is encoded as part of a memory trace
What neurotransmitters are in both Parkinson’s and schizophrenia?-
- dopamine
What is retrograde amnesia and how do you test it?
When you loose memories from the time of trauma going back in the past. you test it by doing the famous faces test. the famous’s faces test is when you present patient with faces from over the years if they can’t remember the name it shows when they first can’t remember
what do abnormal sensation caused and what are they caused by?
When abnormally firing neurons recruit other neurons and start firing abnormally together in parts of the brain that cause sensation - this causes seizures
What are the three proposed components of STM?
the central executive (in command) visuospatial sketchpad (inner eye) Phonological loop (inner eye and inner voice)
What are factors of short term memory and long term memory? how does short term information get into ltm?
has limited captivity and has rapid forgetting of about 20 seconds
massive capacity and slow forgetting. gets into ltm through encoding and rehearsal
What is the serial position effect ?
When a list of 15 words are read out and it is found to have a recency and primacy effect as demonstrated by the model of memory
What is the primacy and recency effect? how does distraction before recall effect them?
primacy - when there is improved performance from the start of the list as words have time to be rehearsed and encoded into LTM
recency - When performance of words at the end of the list can be remembered due to words still being in STM
Recency effect will decrease as words won’t be converted into LTM and will have been forgotten in STM through lack of rehearsal
what is anterograde amnesia and how does it occur?
when you can’t remember LTM and are no longer able to form LTM but STM is still intact. Generally occurs due to temporal lobe damage
What happened to patient H.M ?
Had a head injury causing him life impacting seizures. To reduce this doctors removed his temporal lobes. removal of temporal lobes caused retrograde and anterograde amnesia. He couldn’t remember 2 years before the time of the trauma and couldn’t form new memories
Liable in psychology means?
means a memory is easily changed or easily damaged
what’s temporal lobe amnesia and what causes it?
Disruptes episodic memory and is caused by Damage to mediocrely temporal lobe
What is episodic memory, priming and still learning?
episodic - memory of episodes that have occurred
priming - When someone with amnesia is given a word and when shown again they remember what it was but don’t remember originally being shown it
still learning - When you can do a task easily but can’t remember learning how to do it
what is transience/memory decay and trace decay?
transience/memeory decay - Reduced memory over time
trace decay - when forgetting occurs as a result of the automatic decay or fading of the memory trace. Occurs through the weakening of synapses in LTM
what is blocking/retrieval failure, absent mindless and memory persistence?
blocking/retrieval failure - feeling of knowing but can’t exactly remember
absent mindless - Occurs when you have a memory failure which results in shallow encoding of information due to the lack of attention
memory persistence - when ptsd occurs
what’s distortion and what do the components of it mean?
distortion = masattribuation, bais and suggestibility
mattatribuation - Assigning memory to a wrong source
bais - influence on current knowledge on memory for past events
suggestibility - Altering a memory because of misleading information
what is reconsolidating?
when you continue to build on memories
What is ebbinghouse forgetting curve and what does he suggest?
Shows the rapid fall of retention interval over a month and suggests we retain information for a long time
What was Patersons vs pertesons experiment
Shows decrease of retention interval of recall of letters in seconds
how does memory occur?
through patterns of activity and strengthening of synapses
What is phonetic and semantic encoding ?
phonetic - idea that in STM information is encoded in a shallow form
semantic - when memories are encoded into LTM due to added meaning of the memory. added meaning links to the deeper part of the brain where deep processing occurs
What is the Stein and Branford experiment and what did it show? - base sentences
They gave people a range of sentences with different bases e.g “the fat mad read the sign”. it showed That elaborating rehearsal enhances encoding and engaging with the meaning
what is maintained rehearsal?
Repeating words without thinking about the meaning
In Crash and tuckings experiment what did the experiment show?
That words using semantic memory was remembered the most
What happened in Bradford and Johnsons experiment and what were the results? - paragraphs
Two groups one given a paragraph of meaning an one group given a random paragraph. the group of meaning remembered 32% and the group with no meaning remembered 13%
what are semantic networks and how are they important?
They are series of important information stored in long term memory. they help links concepts in a memory to another e.g firetruck and red
what’s a circadian rhythm?
physical mental and behavioural changes that follow a 24 hour wake cycle
what’s melatonin and where is it released from?
- hormone that makes you sleep
- released from the pineal gland
what’s sleep propensity ?
readiness to transit from awake to asleep or the ability to stay asleep
what is zeigeber?
a rhythmically natural phenomenon that acts as a cue in regulation of the body circadian rhythms e.g light
What does an increase in temperature during wake maintenance zone show?
decrease in metabolism. when your sleeping metabolism decreases by 10% as the body temp decreases the caloric demand
What does Michel siffre experiment and what does it show?
sleep wake cycle - went in a cave and and tested if we have an internal clock
shows that periods of activity sill occurs in a block of time and overtime you become an hour out of sync as humans have an internal clock of 25 hours
What is the slprachiamsmatic nucleus (SCN) and what happens when you remove it?
Where the internal clock is located and if you remove it then you’ll sleep in random blocks across the day instead of only when its dark
how does the scn tell when its dark, keep the sleep wake cycle on time and what does it do when it becomes light?
- can tell when its light because Melatonin receptors in respond to the presence of light by transmitting that information
- when its light or becoming morning the SCN stops the pineal gland from producing melatonin
- it keeps the sleep wake cycle on time by exposure to light
what’s the evolutionary, inactivity and sleep conservation theory?
evolutionary theory - that the core function of sleep is to adopt animals to there specific scientific niche
inactivity theory - not effective and safe to hunt during the night so evolution has caused us to sleep during the day
sleep conservation - when your sleeping you conserve energy so its inefficient to look for food
What is the repair theory and how do sleep and chromosomes link?
repair theory - Muscle growth, tissue repair, protein synthesis and growth hormones occur well sleeping. When sleeping chromosomes dynamics in an individual neurons and at night chromosomes move around which corresponds with repairing double stranded breaks
How do sleep deprivation link to health?
can increase risk of cancer, diabetes, digestive and mood disorders
what occurs from stage 1 to four of sleep?
egg becomes more synchronised
- is it true or false that external stimuli can be incorporated into dreams?
- Is it true or false that dreams only last an instant?
- is it true or false that some people don’t dream?
- Is it true that being aroused when you wake up is due to a sexual dream?
- Is it true or false you only dream in black and white?
- true - test by pouring water on their hand and then asking what they dreamed about.
- false - measure how long they have been in rem sleep then wake them up ask how long they have been dreaming
- false
- false - its a illogical process
- false
what is rem sleep and what does the egg suggest during this time?
low voltage, high frequency waves and during this time there rapid eye movement and loss of muscles tone
egg suggests That neutrons are doing multiple things and that electoral potentials aren’t being synchronised causing the amplitude to drop away
how to test if sleep helps memory
paired associated test an mirror drawing. comparing performance without sleep, after only having SWS and after having LWS
—– memory is increased in early sleep
late sleep increases…….
that early sleep is used for explicit memory and late sleep helps consolidation for skill task
what was the experiment design testing insight and creativity well asleep and what were the results? WHO
participants are presented with a sequence before training and after sleep or controlled condition. found that people who sleep in between tests gained more insight
what is brain plasticity?
refers to a brains ability to change and adapt as a result of experience
what is hypnagogic?
Involuntary sponstanueos dream like experiences that incorporate recent wake experiences
does door increase memory ins sleep?
was found that is enhances decorative memory in SWS and enhances procedural memory in REM sleep
What are sleep spindles and what do they reflect?
eeg spindle density in neocortex during sleep predicts subsequent memory performance and they reflect engagement of replayed experiences with info in the neocortex
What is the hippocampus, what does it do during slow wave sleep and what is encoded in there?
it is the region where memories and experiences are encoded in the firing of neutrons. During slow wave sleep it replays events as a sequence of cell firing. experiences and memories are encoded into the hippocampus
what happens to memories of experiences during Sleep?
experiences are replayed at high speed during SWS
placebo
an inactive treatment, sometimes called a ‘sugar pill - sometimes make you perceive you think you know something
placebo
an inactive treatment, sometimes called a ‘sugar pill - sometimes make you perceive you think you know something
what’s an agonist?
- drug that mimics the action of a normal neurotransmitters by binding to the receptor which produces a response similar to intended chemical. e.g vending machine - put in a metal disk which mimics the action of a coin producing an intended reaction
what’s an antagonist?
drug that binds to the receptor site stopping the receptor from producing a response. egg vending machine - jamming slot so your unable to get a drink
what’s the process of motor alpha neurons?
- sensory inout travels doen the SNS via sensory neuron
- synapses is the spinal cord release NT which sends Ap to the brain
- exhibitory input activate motor neurons causing the muscle to contract
what do alpha motor neurons do?
-helps body generate movement. when alpha motor neurons are activated it causes muscle fibres to contract and generate force
what is inhibitory input?
rather then depolarising the glee it hyper polarises it pushing gp away from the threshold. works to stop muscles tensing
what’s a post synaptic neuron?
at an axon terminal. when neurotransmitters are released across the synaptic cleft the receptors at the post synaptic neuron respond to the neurotransmitter and generate an GP
what’s on the outside of a cell?
both positive and negative charge but there more positive on the outside
there’s also positive sodium ions
what’s on the inside of a cell?
more negative charge
-chlorine ‘and anions
what are the three types of reflexes
steorytypes
subconscious
unlearned
what’s the order of the motor neurons making muscles move?
- sensory inout - travels to CNS via sensory neuron
- synapses in spinal cord release NT which sends AP to the brain causing a sensation
- expiatory NT activate motor neurons sending an AP to muscle which causes the muscle to contract
what did Miller 1956 investigate?
the magic number 7+2 which is capacity of STM
what did stein and brandofrd find?
that elaborative endcoding enhances encoding in LTM
Bransford and Johnson experiment and results
-two paragraphs one with context one without
informed - 32% remembered
Uninformed- 13% remember
concluded that encoding improves comprehension and memory
what happened to formula one driver?
had retrograde amnesia which suggested that memory is consolidated over time
what in consolidation?
that is occurs over peiords and memeories are made damage resistant
what did they do in the Wagner sleep insight study
had to figure out task
what’s hypotonia?
involuntary dream like experiences where recent dream wake experiences are incorporated into stage one of sleep
