Neurotransmitters & Their Effect on Behaviour (DP IB Psychology)

False.

Anxiety and depression are two examples of mental health problems associated with low levels of serotonin.

Two examples of studies that explore the link between neurotransmitters and behaviour:

• Fisher et al. (2005) studied the link between romantic love and dopaminergic activity in the brain

• Brunner et al. (1993) in his case study of abnormal, anti-social behaviour in one family explained by a dysfunctional MAOA gene (linked to the 5-HT) gene

The aim of Fisher et al.'s (2005) study is to investigate a possible link between dopaminergic brain regions and the early stages of romantic love.

Fisher et al. (2005) uses a self-selected sample of:

• 10 female and 7 male students from New York State University

• aged 18-26 years old

• all reporting being 'in love'

According to Fisher et al. (2005), dopamine is associated with romantic love.

In the Fisher et al. (2005) study, the areas of the brain most active when the photograph of the romantic partner is viewed are the right ventral tegmental areas and the right caudate nucleus.

False.

Fisher et al. (2005) finds that romantic love activates the ventral tegmental area and the caudate nucleus, dopamine-rich brain regions.

True.

The findings of the Fisher et al. (2005) suggest that romantic love may fall under the same brain framework of craving and withdrawal. This is because the study supports previous research into the role of dopamine in substance addiction.

The aim of Brunner et al.'s (1993) study is to investigate the violent, anti-social behaviour of specific male members of a large family in the Netherlands.

The participants in Brunner et al.'s (1993) study are:

• 5 males from a family in the Netherlands

• all with the same genetic condition transmitted via the X chromosome on the MAOA gene

• all of the affected males acted aggressively when angry, fearful, or frustrated

The Brunner et al. (1993) study is a quasi experiment because the IV is naturally occurring i.e. it can’t be manipulated by the researcher – in this study, the individuals involved either had the faulty gene or they didn’t have the faulty gene.

False.

Brunner et al. (1993) identifies a deficiency in the neurotransmitter serotonin among the affected males, linked to the MAOA gene.

The findings of the Brunner et al. (1993) study suggests that irregular serotonin metabolism could be responsible for low IQ and aggressive, anti-social behaviour.

Brunner et al.'s (1993) research cannot conclusively support the idea that the affected males’ anti-social behaviour was as a result of serotonin deficiency. This is because their anti-social tendencies may have been influenced by nurture e.g. aggression from others.

Agonist neurotransmitters are molecules that bind to synaptic receptors and activate them to promote a reaction, such as neurotransmission within the synapse.

Antagonist neurotransmitters are molecules that bind to synaptic receptors and decrease the effect of the neurotransmitter, unlike agonists.

False.

An example of an agonist neurotransmitter is an antidepressant that increases the effect of a neurotransmitter like serotonin, such as SSRIs.

Antidepressant drugs like selective serotonin reuptake inhibitors (SSRIs) prevent the reabsorption of serotonin back into the presynaptic neuron, increasing the amount of serotonin available to travel around the brain.

True.

An example of an antagonist is a drug that decreases the effect of dopamine, such as ecicopam.

Dopamine antagonists stop dopamine from binding with receptors in the post-synaptic neuron, preventing feelings of reward, pleasure, and motivation.

Crockett et al. (2010) used a lab experiment to investigate the role of SSRIs (antidepressant drugs) in prosocial behaviour.

Romach et al. (1999) used a natural experiment to investigate the effectiveness of a dopamine antagonist on participants with cocaine addiction.

False.

The aim of the Crockett et al. (2010) is to investigate the role of a serotonin agonist (specifically SSRIs) in prosocial behaviour.

The participants of the Crockett et al. (2010) study are:

• 24 males from Cambridge (UK) with a mean age of 25.6 years

• screened for psychiatric and neurological disorders

A double-blind design is an experiment in which neither the experimenter nor the participants know the aim of the study.

A double-blind design is used in the Crockett et al. (2010) study as neither the participants nor the researcher know whether each participant is given:

1) an SSRI drug (Citalopram)

2) a drug for ADHD

3) a placebo

They are then asked to make moral judgments on hypothetical scenarios.

a.

In the Crockett et al. (2010) study, participants the SSRI condition made more prosocial responses e.g. by condemning harmful actions.

True.

The conclusion of the Crockett et al. (2010) study is that some SSRIs may function as serotonin agonists, enhancing the effect of the serotonin in the brain which in turn may promote prosocial behaviour.

The use of a double-blind procedure increase the internal validity of the Crockett et al. (2010) findings.

It is a limitation of the Crockett et al. (2010) study that is uses an independent measures design as the differences in prosocial behaviour could be due to participant variables. E.g. participants in the SSRI group may simply all have been naturally more prosocial than those in the other two groups.

The aim of the Romach et al. (1999) study is to investigate the role of a dopamine antagonist (ecopipam), in the treatment of cocaine addiction, using cocaine addicts as the participants.

True.

The procedure of the Romach et al. (1999) study involves participants being given different dosages of ecopipam (dopamine antagonist) and injected with cocaine, assessing the effects on measures like euphoria and desire to use cocaine.

The conclusion of the Romach et al. (1999) study is that ecopipam, acting as a dopamine antagonist, may effectively reduce cocaine craving and its effects.

The use of self-reported data is limitation of the Romach et al. (1999) study as it is prone to social desirability bias e.g. the participants may have reported reduced feelings of craving to please the researchers or to project a more positive image of themselves and their recovery from drug addiction.

True.

The Romach et al. (1999) study has useful application as the findings could be used to inform further treatment of cocaine addicts, and possibly those addicted to other substances such as alcohol

During the process of neurotransmission, small sacs (vesicles ) containing the neurotransmitter are released into the synapse to the post-synaptic neurone where cells containing receptors may trigger a change in the cells.

True.

Excitatory synapses release neurotransmitters that trigger an electrical signal in the post-synaptic neurone, increasing the likelihood of firing an action potential.

True.

Glutamate is an excitatory neurotransmitter which has functions including digestive health, memory, learning and strengthening the immune system. Too much glutamate can lead to some neurodegenerative diseases e.g. Alzheimer's disease.

Inhibitory synapses release neurotransmitters that block electrical signals in the post-synaptic neurone, decreasing the likelihood of firing an action potential.

The inhibitory neurotransmitter gamma-aminobutyric acid (GABA), plays a role in relieving anxiety, aiding concentration, and improving sleep.

True.

An example of an artificial food additive that may contribute to psychiatric illnesses is monosodium glutamate (MSG).

An increase in gamma-aminobutyric acid (GABA) has been linked to improved mood, anxiety, through yoga practice (Streeter et al., 2010)?

Kraal et al. (2020) explored research into the link between a low-MSG diet and improved pain symptoms and better mental health.

If a neurotransmitter blocks an electrical signal, preventing it from being transmitted down the cell, is it known as an inhibitory neurotransmitter.

False.

The aim of the Streeter et al. (2010) study is to investigate whether yoga is linked to improved mood, decreased anxiety, and GABA levels.

The procedure of the Streeter et al. (2010) study is:

• Participants are instructed to practice yoga or a walking exercise for 60 minutes, three times a week, for 12 weeks

• Mood, anxiety, and GABA levels are measured at intervals

False.

Streeter et al. (2010) used magnetic resonance spectroscopy (MRS), which measures metabolic changes, not structural changes like MRI.

In the Streeter et al. (2010) study, a positive correlation is found between mood and GABA levels. This means that practicing yoga increased mood and GABA levels in the thalamus.

It is a limitation that the Streeter et al. (2010) study does not conduct a follow-up study with participants as this means it is unclear if the benefits of the yoga were short-term or long-term, limiting the understanding of the intervention's lasting effects.

It is a strength of the Streeter et al. (2010) study that it has a duration of 12 weeks, as this allows for measurement and comparison of changes in mood and GABA levels over time.

The aim of the Kraal et al. (2020) study is to investigate the role of dietary glutamate (MSG) in chronic pain and psychiatric disorders.

Glutamate is an excitatory neurotransmitter.

True.

Glutamate as a dietary source can be found in the food flavouring additive MSG e.g. in soy sauce, parmesan cheese, meat, and many processed foods such as canned soup.

False.

Kraal et al. (2020) conducted a review article, not an experimental study. They reviewed previously published research on dietary glutamate (MSG) and its effects on chronic pain and psychiatric disorders.

In the Kraal et al. (2020) study, an excess in dietary glutamate is found to link to chronic pain and psychiatric disorders such as anxiety, PTSD, OCD, schizophrenia, and depression.

False.

A strength of the Kraal et al. (2020) study is the comprehensive review of existing research (secondary data), allowing for a broad analysis of the topic.

The use of secondary data can be considered a limitation of the Kraal et al. (2020) as it means that the researcher has not had any control over the conditions in which it was obtained, reducing the reliability of the findings.