Biological Approach “Additional Terms”
IB Psych Paper 1 Review

Travis Dixon Biological Psychology 6 Comments

Struggling with agonists, antagonists, neural pruning, etc. etc.? This post will help.
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In the new IB Psychology guide they “clarified” their expectations by adding a number of new terms to the syllabus. For the biological approach, this has added significant content and quite a bit of confusion. This post aims to simplify the requirements and help you find the right studies for the right examples.

The full “Additional Terms Review Guide” is available as a PDF for ThemEd Customers. All you need to do for your copy is simply visit our online store and write a review for one of our products.

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Biological Approach

Term

Definition

Example

Study & Relevance

Neural network

A neural network is a series of connected neurons that allows the processing and transmitting of information. Specific networks are responsible for specific tasks. Neural networks associated with learning and memory develop through adolescence. Squelia et al. (2013) (link) shows how neural pruning strengthens the neural networks associated with cognitive tasks.
The PFC and amygdala connectivity are connected through neural networks, which helps to process emotion. Passamonti et al. (2012) (link) shows how low serotonin might disrupt the neural networks connecting the PFC and amygdala.

Neural pruning

Neural pruning (aka Synaptic pruning) happens when we lose these synaptic connections in a neural network because we do not use them. Neural pruning during adolescence. Squelia et al. (2013) (link) shows how neural pruning can help improve cognitive tasks because kids with thinner cortices scored better on cognitive tests.
Stress may accelerate neural pruning during adolescents. Luby et al. (2013) (link) shows a correlation between stressful life events and hippocampal development in children.

Neuron*

A neuron is a type of cell that receives, processes, and transmits information through electrical and chemical signals.

*It is unclear how this will be phrased in an exam question.

 

This image shows two neurons connected in a neural network. Information is communicated through chemical and electrical signals facilitated by the transmission of neurotransmitters at the synapse. Neural pruning is when these synaptic connections are lost.

Term

Definition

Example

Study & Relevance

Agonist

A chemical that amplifies the effect of a neurotransmitter by binding to the receptor sites of that neurotransmitter and activating them.

Neurotransmitters themselves can be endogenous agonists.

Serotonin can be considered an endogenous (naturally occurring) agonist of 5HT (serotonin) receptor sites. Passamonti et al. (2012) (link) shows how reduced serotonin reduces activity in the PFC.
Pramipexole & Depression: Pramipexole binds to dopamine receptors and can reduce depression. Cusin et al. (2013) (link) found that taking pramipexole reduced symptoms of depression.
Ecstacy (MDMA) & PTSD: MDMA binds to serotonin receptors and may reduce symptoms of PTSD. Mithoefer et al. (2019) (link) found participants taking MDMA had reduced PTSD symptoms.

Antagonist

A chemical that reduces the effect of a neurotransmitter by binding to and blocking the receptor sites of that neurotransmitter. Ketamine, Glutamate & Depression: Ketamine binds to glutamate receptors and can reduce symptoms of depression. Lapidus et al.( 2014) (link) found that taking ketamine had reduced symptoms of depression.
Ketamine & PTSD: Ketamine binds to glutamate receptor sites and could reduce symptoms of PTSD. Feder et al. (2014) (link) found participants taking ketamine had reduced PTSD symptoms.

*Tip: the antagonist in a story stops the hero from achieving his goal, just like in this case the antagonist stops the neurotransmitter (our hero) from achieving its goal of binding to the receptor.

Antagonist

An antagonist binds to the receptor sites of a specific neurotransmitter. An antagonist binds to the receptor sites of a specific neurotransmitter. It can block a neurotransmitter from binding to that receptor site, thus reducing the effect of that neurotransmitter.

Agonist

An agonist binds to the receptor sites of a specific neurotransmitter. It can mimic the action of a neurotransmitter, thus amplifying their effect. Ketamine binds to the glutamate receptor sites and blocks the glutamate from binding. This could help reduce symptoms of depression and PTSD.

Term

Definition

Example

Study & Relevance

Excitatory neuro-transmitters

An excitatory neurotransmitter binds to receptor sites and increases the chances of the post-synaptic neuron firing (sending a signal). Glutamate is an excitatory neurotransmitter. Ketamine blocks the signal of glutamate, which could help PTSD symptoms by reducing hyper-activity in areas of the brain like the amygdala and PFC.

 

Feder et al. (2014) (link) found participants taking ketamine had reduced PTSD symptoms.
Dopamine (is excitatory or inhibitory): pramipexole binds to dopamine receptors, which might stimulate hypo-responsive areas of the brain and reduce depression. Cusin et al. (2013) (link) found that taking pramipexole reduced symptoms of depression.

Inhibitory neuro-transmitters

An inhibitory neurotransmitter binds to receptor sites and reduces the chances of the post-synaptic neuron firing (sending a signal). Serotonin is an inhibitory neurotransmitter. Low levels of serotonin might lead to increases in activity in parts of the brain like the amygdala. Passamonti et al. (2012) (link) concluded that the reduced serotonin might have affected activity in inhibitory neurons in the amygdala, which caused a disruption to the PFC-amygdala connection.
SSRIs increase the availability of serotonin. This might help inhibit activity in hyper-responsive areas of the brain in people with PTSD, like the amygdala. MacNamara et al. showed that taking SSRIs helped reduce symptoms of PTSD and improved function in the PFC during cognitive reappraisal (possibly due to reductions in amygdala activity)
Dopamine (is excitatory or inhibitory): pramipexole binds to dopamine receptors, which might stimulate hyper-responsive areas of the brain and reduce depression. Cusin et al. (2013) (link) found that taking pramipexole reduced symptoms of depression.

 

Term

Definition

Example

Study & Relevance

Twin & kinship studies

A type of correlational study that uses twins and family members to measure the heritability* of behaviour. Twin studies used in the study of antisocial behaviour and aggression. Baker et al. (2007) (link) found the heritability for antisocial behaviour (a risk factor for aggression) was about 50%. More studies (link).
The Minnesota Twin study is a longitudinal twin study that investigates a range of behaviours, including IQ. Bouchard et al. (1990) (link) found that genetics influences intelligence (but so does environment).

*Heritability is the extent to which a behaviour is affected by genetics (technically speaking, it is the extent to which the variation in phenotypes can be attributed to genetic factors.)

 

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Comments 6

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      Author
  1. Looks awesome Travis! I also love your tip on how to remember that the antagonist is one that blocks transmission. I will definitely be coming up with a ridiculous story about neurotransmitter who goes on a grand adventure and encounters an antagonist along the way. And maybe he’ll have a helpful sidekick named Agony? Still working on that one . . .

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      Author
  2. Travis Dixon….You are a ROCKSTAR!
    If given the opportunity….attend one of his workshops…mine experience was “career altering!”

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