Brain Structures And How They Relate To Aggression

Question 1

What are the four lobes of the brain?
What are their functions?

Answer 1

-frontal lobe: problems solving, decision making. If this is nt working you choose wrong decisions.

-pariental lobe: controls your senses

-temporal lobe: used for emotions (overactive-aggressive)

-occipital lobe: sight.

Question 2

What is the cerebellum for?

Answer 2

Movement.

Question 3

How is the brain split?

Answer 3

In half- 2 of everything.
Connected via corpus callosum.

Question 4

What is trepanning?

Answer 4

Surgical invention in which a hole is drilled into the skull to treat problems related to the surface of the brain.

Question 5

Describe the case of phineas gage.

Answer 5

-He was a railway worker in the mid west USA.
-1848:he suffered an accident when tamping iron. He set off the explosive under a rock and blew the iron rod up through gages face sad out the top of his head.
-for the 11 years rest of his life his personality had a fundamental change, he used to be a reliable religious respectful man but turned irresponsible and aggressive.

Question 6

What did the doctors conclude about phineas gages case?

Answer 6

That’s tge damage done to his brain, severing the prefrontal cortex and partially the temporal lobe, lead to a change in character.

This shows how the prefrontal cortex has an impact on behaviour and aggression.

Question 7

What did phineas gages study show?

Answer 7

That damage to frontal lobes seem to cause an increased in aggression.

Question 8

What are typical studies into the biological structures that underl;one aggression tested with?
What three different types of behaviour do they show?

Answer 8

Rodents and cats.
-offensive behaviour, where they physically attack another animal.
-defensive behaviour, shown in response to threat of attack.
-predatory aggression, which involved attacking another species to gain food.

Question 9

What does the midbrain contain and what is its role?

Answer 9

It contains an area called PAG which links the amygdala and hyptohalamus with eh prefrontal cortex.
It has a role in coordinating and integrating behavioural responses to internal and external stressors such as pain and threat.

Question 10

What do lesions in PAG (the midbrain) show?

Answer 10

activated behaviour associated specifically with one type of aggression stimulation of
-medial hypothalamus in a cats brain to produce offensive behaviour.
-the dorsal hypothalamus producing defensive behaviour.
-the lateral hypothalamus resulting in predatory behaviour.

Question 11

What are the 3 main brain parts for aggression?

Answer 11

Amygdala
Hypothalamus
Prefrontal cortex

Question 12

What is the role of the amygdala?

Answer 12

Responsible for emotions, emotional behaviour and motivation.

Question 13

What’s was Raines (1997) amygdala human research?
What did he compare? What did he find?

Answer 13

He compared murderers and non muderers.
Found that there was a significant brain difference between them both.
Murderers had lower glucose metabolism in the left amygdala and greater right amygdala activity.

Question 14

What may abnormalities in their functioning and amygdala relate to? (Raine 1997)

Answer 14

Abnormalities in their functioning may relate to failure to learn from experience displayed by criminal violent offenders.
Abnormalities in amygdala could be relevant as it may lead to fearlessness, so may reduce emotional responses.

Question 15

Amygdala animal research (downer 1961)
What did he do? What was the results? What did it provide evidence for?

Answer 15

He removed part of the amygdala in monkeys and optic nerve got cut.
Monkeys received visual signals that either went to the intact amygdala or removed amygdala.

If monkeys had visual input that connected to the intact amygdala, they reacted in their normal way to humans (aggressive)
If their visual input had no amygdala to reach, the monkeys were much calmer and placid.

This provides evidence for the amygdala being involved in aggressive response to perceived threat.

Question 16

What is the role of the hypothalamus?

Answer 16

Controls homeostasis, regulation of hormones.

Question 17

Hypothalamus aggression human research (Alpers 1937)
What did he study? What was the outcome? What was the conclusion?

Answer 17

He studied a well-liked, mild-mannered, middle aged lawyer who wad later shown to ave a tumour in the medial hypothalamus.
He began to display uncharacteristic outbursts of aggressive behaviour that were shocking to all the knew him.

The localised tumour in the medial hypothalamus was said to be the cause of his uncharacteristic violence.

Question 18

Hypothalamus aggression animal research (Hess 1928)
What did he do? What was the results?

Answer 18

He demonstrated the ability to induce aggressive behaviour in cats by electrical stimulation of the hypothalamus.
The electrical stimulation of the hypothalamic attack area in the medio-basal hypothalamus in rats and cats alicited in biting attacks.

The densest projection (area in the brain that sends the most nerve fibres/connections to a specific brain region) of the HAA originated in the pre-frontal cortex; damage to this area implicated in human aggression.

It was also found that brain stem simulation in the central grey area produces hitting and characteristic vocalisations.

Question 19

Wheat is the role of the prefrontal cortex?

Answer 19

Planning and decision making.

Question 20

Prefrontal cortex aggression human research (raine 1997)
What did he find? What did researchers conclude?

Answer 20

Found that murderers had lower levels of glucose metabolism in left and rigbt prefrontal cortex relative to controls.
-damage in this area of the brain can result in impulsivity, loss of control, immaturity and inability to modify behaviour, these Turin into aggressive acts.

Researchers concluded that offenders who had shown emotional impulse aggression had not been able to regulate their behaviour due to this low level of functioning.

Question 21

Prefrontal cortex aggression human research (phineas gage)

Answer 21

Iron rod was driven through his head, damaged pre frontal and medial lobes of the brain.
After incident his personality changed from respectful and religious to irredentist and impulsive.
Caused him to lose his job.
This gave insight intimately particular regions of the brain as controlling aspects of our personality.

Gages behaviour problems following the accident concurs with several other individuals with damage to the same brain region. (Demaiso 1994)

Question 22

Positive evaluation of brain structure relating to aggression.

Answer 22

-animal experimentation greatly improved our knowledge of aggression and the underlying neurobiology
-similarities between animals and humans in terms of brain structure making generalisation possible.
-measurements are reliable and scientifically credible as PET and FMRI scans have ore precison. Brain structures can be isolated and measured in a variety of ways.

Question 23

Negative evaluation of brain structures relating to aggression.

Answer 23

-scanning may be highly reliable but there may be issues of validity because the scan has to take place in artificial settings whilst attached to scanning device. Doesn’t reflect everyday life.

-generalisation from animals are problematic for many reasons, although some animals have the same brain structures, they have a smaller prefrontal cortex.