3 replies to this topic

[Hinuku]

I have these 3 questions to answer, I'd appreciate some help


1. Describe one brain imaging technique. /8 marks/
2. Outline one theory of sleep function. /8 marks/
3. Explain function of two hormones in human behaviour. /8 marks/


Thanks!

[blindpet]

Describe one brain imaging technique. /8 marks/

fMRI stands for functional magnetic resonance imaging. It uses a large magnet to detect blood flow chances in the brain using the BOLD signal. It can record ongoing activity and has greater spatial resolution than PET meaning it can see more detail than PET. Various tasks can be given to participants while they are in an fMRI which can be used to see which brain areas are activated under different tasks.

Outline one theory of sleep function. /8 marks/

Not in the syllabus, so you'll have to look at your notes. I know one has to do with consolidation of memory.

Explain function of two hormones in human behaviour. /8 marks/

This question should be one function of a hormone on behavior, not two.

Vasopressin is a hormone that has been linked to fidelity. One study on prairie and meadow voles revealed that having a different vasopressin gene was associated with pair-bonding style (Winslow et al., 1993) . Male praire voles were monogamous and paired with females for long periods whereas meadow voles tended to be polygamous having many different female partners. Another study found that vasopressin was also linked to pair bonding in humans (Walum et al., 2008). They found that men carrying a specific form of a vasopressin gene were considered 'commitophones' according to a questionnaire (fear of commitment etc). Men with another form of the vasopressin gene were more likely to be in committed long lasting relationships.

[sarahlouise]

Heh, we've just covered these very recently in class. (except for number 2 sorry).

1) fMRI is a functional Magnetic Resonance Imaging. It provides 3-D pictures of the brain structures using magnetic fields and radio waves, shows actual brain activity, and indicates which areas of the bran are active when engaged in behaviour. (Taken from Psychology IB Course Companion)
The advantages of the fMRI are that it's practical, as most hostpitals already had MRI scanners and they were easily converted into fMRI scanners. Also, it has high spatial resolutions of 2-3 cubic millimetres. It doesn't require the use of radioactive injections like the PET scan, so the individual can be repeatedly tested. Also, localising brain activity during a task is easier, so the data can be collected all in one session. (All this according to Brooks Jamison, 2010)
The disadvantates are that there is concern about accuracy - it gives correlation between cognitive tasks and brain activity, not statements about causation. Blood flow to the brain is fairly slow, so the image is recorded more slowly than actual neural activity. There's also concern that it's not as legitimate as we like to think. Because it uses univariate (one variable) algorithms to process data, this may make it seem that the brain activity is more localised than it is in reality (Dobbs 2005). In addition, there's a lot of room for error because images can be overinterpreted. (This is also all according to Brooks Jamison, 2010)

3) Testosterone and aggression:
Mehta + Beer (2010) - testosterone increases the propensity toward aggression because of reduced activity in the medial orbitofrontal cortex. Testosterone isn't related to all forms of aggression, but may specifically control impulsive aggression in response to a social threat (real or perceived).
Dabbs et al - criminal violence and aggressive dominance among women in prison is linked to higher testosterone levels.
Rasanan et al (1999) - psychiatric disorders that include symptoms of impulsive aggression are associated with high levels of testosterone.
According to Natasha Mitchel (abc.net, a reliable Australian network), testosterone levels are highest among inmates convicted of violent crimes like murder, assault and rape.
Oxytocin:
Oxytocin is the 'love' or 'trust' hormone, and might have a role in human social bonding, as well as having a function in stress reduction. It's involved in several forms of social attachment in mammal mothers.
Hold-Lunstad et al (2008) - oxytocin levels rose after an increase in positive physical contact between husband and wife, and the husband's blood pressure decreased.
Morhenn et al (2008) - oxytocin levels helped people display trust towards strangers, which suggests that oxytocin's effect on behavour is to increase generosity and cooperation among adults.

@blindpet, it's two hormones. The syllabus has probably changed since you completed IB.

Sorry if this was too much information...I got excited because I knew the answers

Edited by sarahlouise, May 31, 2011 - 22:42.

[blindpet]

@blindpet, it's two hormones. The syllabus has probably changed since you completed IB.

The syllabus has certainly been revamped completely . I know you need to know two, but on the May 2011 paper the 8 mark question was 'Explain one function of a hormone on behavior' (if I remember correctly)


I should've made myself clearer by saying that although you do need to know 2 functions of hormones on behavior you will not get that question as an 8 marker cause you simply can't write the answer for two hormones in the amount of time allocated without omitting necessary info (is what I think they're thinking).

I should also note that the examiner I'm in contact with said if you use a neurotransmitter instead of a hormone for this specific question you will gain 0 marks for your answer, the opposite is also true (using a hormone if you asked about a neurotransmitter's effect on behavior).