1. Explain Effects of Neurotransmission on Human Behavior
Explain – Give a detailed account including reasons or causes

2. Explain Effects of Neurotransmission on Human Behavior
Neurotransmitters affect everything you do and everything you do affects neurotransmitters.
Genes and hormones affect neurotransmitters, which then affect behavior
Learning, psychotherapy, stress and food affect neurotransmitters

3. Explain Effects of Neurotransmission on Human Behavior
Serotonin on Prosocial Behavior:
Crockett et al (2010)
Aim: to investigate the effect of serotonin on prosocial behavior
Methods:
A sample of volunteers was recruited for the study, which included 30 healthy subjects (average age of 26)
The experiment followed a repeated measures design with two conditions.
In condition 1, participants were given a dose of citalopram (a highly selective serotonin reuptake inhibitor, SSRI)
In condition 2, participants were given a placebo.
The design was counter-balanced, and this was a double-blind study.
After taking the drugs, participants were given a series of moral dilemmas that involved choosing between utilitarian outcome (saving five lives) and aversive harmful actions (killing an innocent person)
Aversive harmful actions in the scenarios were of two types: personal (for example, pushing a man off a bridge to stop a train and prevent it from hitting five people) and impersonal (for example, pressing a lever to divert a train off a track where it will hit five people to a track where it will hit one).

4. Explain Effects of Neurotransmission on Human Behavior
Results of Crockett et al (2010):
Responses in the impersonal version were unaffected by citalopram
However, after receiving a dose of citalopram, participants were less likely to push the man off the bridge in the personal scenario than participants in the placebo condition.
After receiving doses of citalopram, participants opposed the idea of pushing a man off the bridge even more
Researchers concluded that serotonin reduces acceptability of personal harm and in this way promotes prosocial behavior.
It controls reactions of the brain to emotionally striking situations so that inflicting harm on other people is judged as less acceptable
A limitation to this study is that citalopram intake induced slight nausea so it is not possible to estimate the extent to which this might have influenced the results.

5. Explain Effects of Neurotransmission on Human Behavior
The effect of Dopamine on romantic love:
Fisher, Aron and Brown (2005):
Aim: to investigate the neural mechanisms of romantic love.
Methods:
ten men and seven women who were currently “intensely in love” (but not with each other) were recruited for the study by word of mouth as well as through flyers.
The mean age was 21 and the mean reported duration of being in love was seven months.
All participants were placed in a fMRI scanner and engaged in a standardized procedure involving looking at photographs while their brains were being scanned.
There were four stages:
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 more seconds, participants viewed a photograph of an emotionally neutral acquaintance.
The final stage was another 20 seconds of counting back from a number
These four steps were repeated six times, so the total procedure lasted for 12 minutes

6. Explain Effects of Neurotransmission on Human Behavior
Results of Fisher, Aron and Brown (2005)
Results showed a specific pattern of activation in the brains of participants in response to the photographs of their loved ones:
activation was observed in dopamine-rich neural systems, primarily the ventral tegmental area (VTA) and caudate nucleus.
Both these regions are rich in dopamine and form the key part of the so-called dopaminergic pathway – a system that generates and transmits dopamine and increases dopamine-related activity in the brain
It is a reward system because dopaminergic activity is associated with motivation and feelings of pleasure.
In this way, dopamine activity in the brain plays a role in romantic love.

7. Explain Effects of Neurotransmission on Human Behavior
The role of dopamine in Parkinson’s disease:
Freed et al (2001):
Aim: to study the role of dopamine in Parkinson’s disease
Parkinson’s disease: degenerative disorder that mainly affects the motor functions of the nervous system.
Methods:
The sample consisted of 40 patients who were years old and had severe Parkinson’s disease, with the mean duration of 14 years
The sample was randomly divided into two groups:
Experimental group received a transplant of nerve cells
Control group underwent sham surgery
In the experimental group, nerve tissue containing dopamine-producing neurons was taken from embryos aborted 7-8 weeks after conception and transplanted into the patients’ putamen – a structure of the limbic system involved in movement regulation.
Local anesthesia was administered to the skin of the forehead and four holes were drilled through the frontal bone, after which the tissue was transplanted through long needles.
In the sham surgery group, holes were drilled in the skull but the dura (a thick membrane that surrounds the brain) was not penetrated, otherwise the procedure was identical
The protocol of the study and the consent form describing the risks and potential benefits were approved by the ethics committee. A separate written informed consent form was used for the women who donated fetal tissue from abortions.
A number of measures were taken before and after the surgery. They included clinical observations and interviews, and brain scans (PET). All patients were followed up longitudinally for one year.

8. Explain Effects of Neurotransmission on Human Behavior
Results of Freed et al (2001)
Irrespective of the age group, PET scans revealed increased growth of dopamine-producing cells in the putamen
A reduction of symptoms by 28% was found in the patients in the transplant group, but only the younger ones (aged 60 or younger). No improvement was registered in the older sub-group of patients (aged over 60).
Overall conclusion was that transplantation of dopamine-producing neurons in the putamen of patients with severe Parkinson’s disease results in some clinical benefit in younger but not older patients. Less response to treatment in the older patients despite successful growth of dopamine neurons may be attributed to lower neuroplasticity of the brain.