Biological - Neurotransmitters (Experiments)

Question 1

Crockett et al (2010) aim

Answer 1

○ The effect of serotonin on prosocial behavior.

Question 2

Crockett et al (2010) design

Answer 2

§ Repeated measures design.
			§ Counterbalanced
			§ Double blind study
		○ Sample
			§ 30 healthy subjects.
			§ Mean age 26

Question 3

Crockett et al (2010) method

Answer 3

§ In condition 1 participants were given citalopram.
□ A highly selective SSRI.
§ In condition 2 (control) participants were given a placebo.
§ Participants were given moral dilemmas
□ Utilitarian outcome
□ Aversive harmful actions
® Personal (pushing a man off a bridge)
® Impersonal (using a lever to divert the train)

Question 4

Crockett et al (2010) results

Answer 4

○ Responses in impersonal were not influenced by citalopram.

○ Participants less likely to push man in personal condition when exposed to citalopram.

Question 5

Crockett et al (2010) conclusion

Answer 5

○ Serotonin reduces acceptability of personal harm and promotes pro-social behavior.

Question 6

Crockett et al (2010) evaluation

Answer 6

○ Citalopram induces slight nausea.
§ Participants might have worked out which condition they were in.
§ Not possible to establish the extent to how this influenced the results.

Question 7

Fisher et al (2010) aim

Answer 7

○ Investigate the neural mechanisms of romantic love.

Question 8

Fisher et al (2010) design

Answer 8

§ 10 men and 7 women intensely in love with non-participants.
§ Mean age 21
§ Mean duration of love 7 months

Question 9

Fisher et al (2010) method

Answer 9

§ All participants were placed in Functional Magnetic Resonance Imaging scan.
§ Four stages were shown
□ For 30 seconds each participant viewed a photograph of his or her beloved person.
□ Participants were given a 40 second filler activity which was to count back from a given number.
□ For 30 seconds participants viewed a photograph of an emotionally neutral acquaintance.
□ The final stage was another 20 seconds of counting back from a number.
§ These 4 steps were repeated 6 times.

Question 10

FIsher et al (2010) results

Answer 10

○ Specific pattern of activation in the brains of participants.
○ Activation was observed in dopamine rich neural systems.
○ Discovery of the dopaminergic pathway

Question 11

FIsher et al (2010) conclusion

Answer 11

Dopamine activity plays a role in romantic love

Question 12

Freed et al (2001) aim

Answer 12

○ Investigate the role of dopamine in Parkinson’s disease.

Question 13

Freed et al (2001) sample

Answer 13

§ 40 patients
§ 34-75 years old
§ Severe Parkinson’s Disease
§ Mean duration of 14 years.

Question 14

Freed et al (2001) method

Answer 14

§ The sample was randomly divided in two groups.
□ Experimental group received a transplant of nerve cells.
□ Control group underwent sham surgery.
§ Transplant group received nerve tissue with dopamine producing neurons taken from aborted embryos.
§ The transplant was placed in the patient’s Putamen.
□ A structure of the limbic system associated with movement.
§ All surgeries were performed with the patient awake.
§ A number of measures were taken before and after the surgery.
□ Clinical observations
□ Interviews
□ Brain scans (PET)
§ Patients were then followed up longitudinally for one year.

Question 15

Freed et al (2001) results

Answer 15

○ Irrespective of the age group PET scans showed increased growth of dopamine producing cells in the putamen.
○ A reduction of symptoms by 28% I patients of the transplant group but only in patients below the age of 60.
§ None for older.

Question 16

Freed et al (2001) evaluation

Answer 16

• Consent and protocol approved by ethics community.

* Separate forms for women donating fetal tissue from abortions.

Question 17

Serotonin depression aims

Answer 17

• Serotonin has been showed to be involved in symptoms of major depressive disorder.
The hypothesis states that low levels of serotonin in the brain play a causal role in developing depression.

Question 18

Serotonin depression method

Answer 18

○ Mainly involved clinical trials
§ One group is given serotonin
§ Control group is given placebo
○ The symptoms of depression will be compared across the two groups.
○ If a drug like SSRI leads to a reduction in serotonin in the experimental group is concluded that the level of serotonin is the cause of depression.

Question 19

Serotonin depression evaluation

Answer 19

○ Drugs affect neurotransmitters in minutes
§ Symptoms may take weeks to form.
○ Speculation that influence is indirect.
○ Taupin (2006)
§ Increased stress can damage neurons in the hippocampus and lead to depression.
§ SSRI’s restore the damaged neurons gradually alleviating the symptoms.
• Presence of a link between serotonin and depression is not questioned.
• Recently depression was linked to a particular gene
○ 5-HTT and this gene was shown to influence one’s vulnerability to depression through stressful events. Caspi et al (2003)