ion channels to behaviour Flashcards
What are the degrees of reductionism?
- Macro anatomical
- Micro anatomical
- Macro molecule level
What is macro anatomical?
- interaction of different brain areas
What is micro anatomical?
- interaction of different brain cells
What is macro molecule?
- interaction of individual protein molecules
How do neurons connect?
- connect at the synapse, joining a terminal button of one neuron to the dendrite of another.
Structure of a neuron.
what does the soma do?
What do the dendrites do?
- soma = integrates information
dendrites = receives information from other neurons, through branches.
What does the axon do in the structure of a neuron?
- gets information away from the cell body to another neuron.
What is an action potential?
an all or nothing response, that occurs when there is a change in charge from the resting membrane in a positive direction.
When is depolarisation triggered?
- at 50mv
What is 50mv?
- the threshold of excitation, meaning an action potential is triggered.
what is the resting membrane potential (RMP)?
- the difference in the + charge outside the cell and the - charge inside the cell. called 70mv
Explain an ion transporter.
- it moves sodium ions outside of neurons and exchange for potassium ions inside cell, creating a shift, causing more moves of sodium ions than potassium.
What is depolarisation?
- membrane becomes less negative
what is the role of the post synaptic neuron?
- output, receives info at the synapse, then takes info out.
what is polarisation?
- membrane becomes more negative?
what does it mean to have something very localised?
- movement of ions is small - more significant near membrane.
What two things change during action potentials?
- permeability of membrane (channels open or not)
- electrostatic pressure (membrane voltage changes)
What is the role of the pre-synaptic neuron?
- the input, bring info into the synapse
what causes depolarisation?
- info transfer between neurons, causes depolarisation.
What is hyperpolarisation?
- chloride channels open - chloride ions go in and make membrane more negative, causing it to be inhibitory (less likely for APs to fire).
What is hyporpolarization?
- Sodium channels opened, sodium flows in, causing it to be excitatory (more likely to cause AP) - the more action potentials the more likely to reach the threshold.
What are ligands?
- a chemical that interacts with a receptor.
Where does the ligand interact?
- at the binding site
Explain selectivity of binding.
only specific ligands will fit into specific receptor types.
What is Affinity?
- how well a ligand binds to a receptor.
(therefor high affinity means that receptors are saturated).
What are the two types of receptors?
- Ionotropic receptor
- Metabotropic receptor
What is ionotropic receptor?
- receptor is “directly coupled” to an ion channel.
(faster process than metabotropic).
What is metabotropic receptors?
- it is where the ligand binds to the post synaptic neuron on the outside, changing it’s 3D shape of the receptor, activating G-protiens, that are connected to the receptor inside the neuron. Activating intracellular signalling cascade.
what are some reasons for why receptors can also be found on the presynaptic neuron?
- due to retrograde signalling
or - negative feedback.
what is retrograde signialling?
- where the signal travels backwards from post to pre.
- can cause an effect on synaptic plasticity.
What are the two types of neurotransmitters?
- amino acids
- monanimies
Describe Glutamate.
- the most abundant NT
- an excitatory NT
- binds to at least 8 different receptors both ion and metabo
Describe GABA.
- most abundant inhibitory NT
- binds to both ion and metabo
Describe Glyicine.
- most unusual
- an amionacid (simplest one chemically).
- binds to inhibitory receptors in the spinal cord.
co-agonist with glutamate at NMDA receptors in the brain
Who said “Neurons that wire together, fire together”?
- Donald Hebb
what does Long-term potentiation do?
- strengthens synaptic connections
- helps encode memories
What is adaptive behaviour?
- experiences can be learnt
- may allow a person to rely on other senses hearing or smell.
(e.g., someone may rely on crossing the road by what they hear rather than actually looking left and right). - more dangerous now that most cars are becoming electric, meaning they are silient.
What is the prediction error?
Lambda - V
What does Lambda mean?
- the maximum amount that could be learnt.
What does v mean?
- what has already been learnt.
What is the learning curve?
- the difference between what could be learnt take away, what we already know.
What does blocking do in terms of learning?
- if something is predicted through an already existing stimulus, than that prediction will be blocked by any type of learning, as it isn’t necessary.
Where are action potentials recorded in?
- the ventral tegmental area (VTA).
What would happen if a prediction error was made during the blocking phase?
- it results in learning as this would not usually happen.
What is memory consolidation?
- the process of making memories stronger by transferring them from the LTM into the STM.
What are NMDA receptors needed for in memory consolidation?
- for memory acquisition, which is also a key part in LTP.
What are the different types of administration of drugs getting in the body?
- oral
rectal
buccal
inhalation
injection
muscle intramuscular
transdermal
What does “dose response curve” mean?
- depending on the drugs half-life it may result in how frequently a person takes drugs in order to feel the effects.
What does Potency mean?
- the amount of drug required to produce a specific effect.
(how strong something is).
What does efficacy mean in terms of drug use?
- the ability of the drug producing an effect.
What are the advantages and disadvantages of route administration of oral and inhaliation?
Oral
+ fast, easy to take
- stomach is acidic drugs are broken down
Inhalation
+ fast, gases leave + enter lungs quickly
- can damage lungs
What are the advantages and disadvantages of transdermal patches and injection?
Transdermal patches
+ long duration of action
- potential for allergic reaction
Injection
+ very fast, allows accurate dosage
- can cause clots and infection
What is a direct agonist?
- binds to and blocks NT receptors, preventing the NT from attaching to receptors.
What is an indirect antagonist?
- dampens NT activity by inhibiting the release/ production of NT.
What is Allosteric modulation?
- chemical modulator which binds to a different part of receptor than receptor, altering the receptor response to the NT.
What is an inverse agonist drug?
- produces the opposite physiological changes to an agonist.
What are some factors that may contribute to different drug effects?
- Individual differences
- experience
- context
How can age affect drug use?
- a person’s metabolism slows down giving less chance of their body breaking down the drugs. e.g., liver is weaker.
How does sex affect drug use?
- women have lower plasma volume, higher proportion of body fat and different response due to menstrual cycle.
How much alcohol can be metabolism per hour?
- 10ml of 100% ethanol can be metabolised per hour.
How does tolerance affect a person’s drug use?
- over time a person becomes use to a drug and feels affects less, meaning they have to up their dosage.
What does Sensitisation mean in terms of drug use?
- means a person is sensitive to the drug and may have to lower or keep their dosage the same.
What is the placebo affect?
- if a person is told a drug will work even tho its a sugar pill, can make a person feel better as they are expecting the drug to have an effect on them.
What factors affect alcohol?
- food in stomach
- sex
- heritage ( a build of acid acetaldehyde causes a person to have a hangover).
What is cellular tolerance?
- neurons adjust their function to compensate for the drug on the cell, this may consist of things such as changing the number of recpetors.
What is the limbic system?
- a group of brain structures that help regulate emotions and behaviour.
What is the amygdala?
- a almond-shape part of the brain that is responsible for emotional control, specifically for fear.
What can damage to the amygdala cause?
- can disrupt the ability to feel fear and learn from it.
Why is fear valuable?
- can help spot danger and protect yourself.
What is memory extinction?
- a conditioned response weakens overtime as it is learnt to separate a response from a stimulus.
What is the James-Lange theory?
- emotions are a result of how the brain may interpret the body’s reaction to an event.
What are emotional responses characterised by?
- subjective feeling
- behavioural
- physiological
- changes in cognition
Give some examples of fear responses?
- changes in
heart rate, blood pressure, pupil size, EEG pattern, respiratory rate and hormone secretion.
What are some changes in behaviour that may occur due to fear?
- avoidance behaviour
- enhanced attention + memory
- adaptive benefits (use of different senses).
Explain what maladaptive means?
- actions that prevent people from adapting or participating in different aspects of life.
What are some maladaptive effects from fear?
- phobias, PTSD and drug addiction.
What is emotion a product of in the brain?
- the brain Kluver.
What is Bucy syndrome?
- a rare brain disorder that can cause memory loss and behavioural problems.
What does PAG stand for and what does it do?
- periaqueductal grey, and it is involved in the selection of defensive emotional responses.
What are 4 diagnostic clusters for PTSD?
- flashbacks
- avoidance
- negative cognitions
- arousal (more reactive)
What is a difference between PTSD and non- PTSD patients in terms of activation levels?
- lower activation of VMPFC in PTSD patients.
What is the difference between PTSD vs(non) patients in their Pre-frontal cortex?
- Non-PTSD patients still have a working PFC meaning they can rain in excessive emotion, whereas PTSD patients have no control over their PFC.
If PTSD patients have no activity in the PFC where do they have activity?
- they have higher activity in the amygdala.
What is Noradrenaline?
- a chemical created in your nerve endings to help a person stay focused and alert.
What can reducing NA do to a person?
- reducing NA can cure PTSD.
How can Beta blockers help with trauma?
- they can prevent memories from strengthening.
What is the role of the amygdala and PFC.
- amygdala is responsible for expressing emotion.
- PFC is responsible for controlling expressive emotion.
If a brain scan highlights the colours red or range of high colours what does this mean?
- it highlights activation in the amygdala.
- excessive emotion caused by the amygdala also highlights damage to the PFC as it is unable to control the excessive emotion.
What does drive theory mean?
- the ability to detect what the ideal body state would be.
What does motivational drive theory mean?
- intentionally moving/changing location or clothing to warm or cool down, in order to get back to set tempreture.
What is anticipatory motivational drive?
- experiences can allow you to anticipate or predict for the future. e.g., get yourself a drink before eating something salty as you are aware the foods will make you thirsty.
What are some rewards from drive theory?
- eating = reward
- avoiding hunger = reward.
What is Hedonic reward?
- unrelated to motivational drive , rewards engage emotions.
e.g., sweetener rather than sugar - still being satisfied.
What is incentive motivation?
- learning
(most behaviour is motivated by learned stimuli) - money is the main motivator.
What is the difference between liking and wanting?
- liking = sensory pleasure
- wanting = motivational incentive value.
