Neurotransmitters and behaviour

Question 1

what are neurotransmitters ?

Answer 1

Neurons, nerve cells, are responsible for behaviour by sending electrochemical
messages to each other.

● When a nerve impulse reaches the end of a neuron, the neuron releases
neurotransmitters into the synaptic gap where they travel to the neuron on the
other side of the synaptic gap.

● If the neurotransmitter isn’t absorbed, it’s re-uptaken, diffused or destroyed.

● The neurotransmitter binds to specific receptors on the other neuron.

● If neurotransmitters are blocked or replaced, this affects the message sent to
the neuron which, then, affects mood, cognition or behaviour.

Question 2

effects of dopamine

Answer 2

Dopamine plays an important role in facilitating movement and speech

When people expect or receive a reward - whether it is a cheeseburger, sex, or scoring the winning touchdown in a football game - levels of dopamine increase in the brain. This results in feelings of pleasure and reward, prompting us to alterour behavior to get more of that reward in the future

Addictive drugs (such as cocaine, heroin, and nicotine) cause huge increases in dopamine levels, leading to the “high” that people feel.

Question 3

study 1

Answer 3

Aron, Fisher and Brown

Question 4

aim

Answer 4

aimed to test the hypothesis that dopamine-rich areas in the brain are linked with being in love

Question 5

method

Answer 5

gathered a sample of 17 participants (10 females and 7 males )

average age of 21

collected sample through word of mouth and flyers

all of them claimed to be in love

average age of courtship was 7 months

they interviewed participants using a semi-structured format and the completed a passionate love scale (PLS) to determine the duration, intensity, and nature of their romantic love

4 steps:
1) while in a functional MRI they were shown a picture of their loved for 30 seconds
2) followed by a 40 second distraction task which was counting backwards from a given number
3) a picture of a neutral acquaintance was shown for another 30 seconds
4) and then a 20 second counting-back task

duration was 12 mins per participant

Question 6

results

Answer 6

distinctly different parts of the brain were activated when they viewed a picture of their loved one versus a neutral acquaintance.
when view pics of their beloved the right ventral tegmental (VTA) and the right caudate nucleus were activated

Question 7

the right ventral tegmantal area

Answer 7

a dopamine rich area of the brain and part of the brain’s reward system

it is associated with pleasure, general arousal, focused attention and motivation to pursue and acquire rewards.

Question 8

the right caudate nucleus

Answer 8

linked with expecting and detecting rewards

Question 9

conclusion

Answer 9

romantic love is associated with dopamine-rich areas of the brain which are linked with motivation and reward sensing which triggers a drive to be in love with the person.

Question 10

STUDY 2

Answer 10

Freed et al

Question 11

information

Answer 11

parkinson’s disease is a degenerative disorder that mainly affects the motor functions of the nervous system.

early symptoms include–> shaking, rigidity, and difficulty with movements and walking.

thinking and behavioural issues may occur with time

Question 12

Aim

Answer 12

to study the role of dopamine in parkinson’s disease

Question 13

Procedure

Answer 13

+ 40 patients
+ 34-75 years old
+ all had severe parkinson’s disease
+ mean duration was 14 years
+ sample was randomly divided into 2 groups
+ experimental group received a transplant of dopamine-neurons
+ control group underwent a sham surgery
+ in the experimental group–> nerve tissue containing dopamine-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)
+ all surgeries were performed with the patients awake
+ local anesthesia was administered to the skin of the forehead and 4 oles were drilled through the frontal bone after which the tissue was transplanted through long needles.
+in the shame 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.

Question 14

Results

Answer 14

-irrespective of the age group, PET scans revealed increased growth of dopamine-producing cells in the putamen
- a reduction of symptoms by 28% was seen in the patients of the experimental group but only the younger sub-group (60 and younger)
-no improvements was seen in the older sub-group

Question 15

Conclusion

Answer 15

+ transplantation of dopamine producing neurons in the putamen of patients with parkinson’s disease results in some clinical benefit in younger patients due to higher neuroplasticity

Question 16

Evaluation

Answer 16

+ the protocol of the study and consent form describing the risks and potential benefits was approved by the ethics community

+ a separate written informed consent form was used for women who donated fetal tissue from abortions

+clinical observations and interviews and brain scans were done

+ all patients were followed up with longitudinally for 1 year.