Techniques used to study the brain and behaviour - fMRI

fMRI (Passamonti et al & Radke et al) AND for MRI being Grafman et al

Studies for fMRI (as a technique used to study the brain and behaviour)

Passamonti et al & Radke et al.

Passamonti et al (AIMS)

To investigate the effects of serotonin levels on the activation of the PFC and the amygdala (during social threat)

Passamonti et al (PROCEDURE)

A true experiment where they used healthy participants and manipulated serotonin levels in the participants. One group had a drink containing tryptophan and the other group a placebo, to help observe brain activity using an fmri. Participants were put into fMRI machines and shown sad, angry and neutral faces to access brain activiation in response to the social cues shown.

Passamonti et al (RESULTS)

The fMRI results showed that participants with lower serotonin levels had decreased PFC activation when shown angry faces and disrupted/weaker communication between the amygdala and the PFC. (Indicating a disruption in that could influence an individuals ability to regulate emotion in response to ‘threat’).

Passamonti et al (CONCLUSION)

This study demonstrates how fMRI can be used to explore the relationship between brain function and behaviour, highlighting the role that serotonin plays in emotion regulation and social threat response.

Passamonti et al (STRENGTHS)

• Double blind procedure (Both the researchers and the participants don’t know who got the altered drink or the placebo) —> reducing the possibility of researcher bias increasing the study’s internal validity

• The use of fMRI as it allowed the researchers to localise activity specific to the PFC and amygdala (supporting claims of the role of serotonin in regulating aggression and emotion)

• Repeated measures design (all participants were exposed to all conditions, reducing participant related variability and increasing the reliability of the findings)

Passamonti et al (LIMITATIONS)

• Low ecological validity (when using fMRI, the study is often conducted in a highly controlled lab environment often lacking real-world context) —> thus the emotional reactions, might not reflect the complex/natural emotional reactions from day to day in more complex scenarios too)

• Small sample size (only 22 participants) may limit generalizability and reliability of results as it is more likely that there the results are impacted by individual differences in serotonin levels and brain activity

Radke et al (AIMS)

To investigate the effect of testosterone on social threat perception and amygdala activation

Radke et al (PROCEDURE)

54 female participants, half were given a small dose of testosterone while the others were given a placebo, before viewing angry or happy faces while undergoing fmri scanning. They were then instructed to either “approach or avoid” these faces using a joystick (where the joystick would either make the faces bigger or smaller depending on their choice). Meant to replicate a real-life scenario when we approach or avoid a social scenario.

Radke et al (RESULTS)

Participants who received testosterone showed increased amygdala activation when approaching angry faces compared to those that received a placebo and were more likely to avoid these ‘scary/threatening’ faces.

Radke et al (CONCLUSION)

That testosterone levels play a role in amygdala activation which may result in a more emotional and aggressive response to perceived social threats.

• Thus highlighting how using fmri is important as it can provide us with insights into the relationship between brain activity and behaviour (e.g. responses to a perceived social threat)

Radke et al (STRENGTHS)

• Double-blind procedure (both the researchers and participants do not know what condition the participants are in)

• Relatively large sample size of 54 women

• Use of fmri allows for direct observation of brain activity during emotional processing.

Radke et al (LIMITATIONS)

• Same as passamonti the research method (laboratory experiment)

• All women (same gender) findings less generalisable and limited = cannot generalise to men (e.g. men have naturally higher levels of testosterone)

• Artificial stimuli (showing images of angry faces cannot replicate complexity of real-life situations and emotions)

Ethical considerations for both

Informed consent = is an important consideration because researchers must carefully consider how much information to reveal to participants and when.

• In studies where levels of e.g. testosterone or serotonin are manipulated and their effects on the brain are measured, informed consent is an important consideration because researchers often use a blind design and placebos for control conditions.

Additional ethical considerations (to consider) being the right to withdraw, confidentiality and even protection from harm.