15.1.1

Neural Mechanisms

Test yourself

The Limbic System

Human aggression can be explained in terms of biological structures, for example, the role of brain mechanisms and hormones. The limbic system and neurochemicals, such as testosterone and serotonin, are also thought to be important.

Illustrative background for The limbic systemIllustrative background for The limbic system ?? "content

The limbic system

  • The limbic system is the network of subcortical structures in the brain (including the hypothalamus and the amygdala) thought to be closely involved in regulating emotional behaviours such as aggression.
  • Papez (1937) made the first attempt to link the limbic system to emotional behaviours such as aggression.
  • This was later revised by Maclean (1952).
Illustrative background for Limic system partsIllustrative background for Limic system parts ?? "content

Limic system parts

The limbic system is comprised of:

  • The cingulate gyrus.
  • Septal area.
  • Hypothalamus.
  • Fornix.
  • Amygdala.
  • And parts of the hippocampus and thalamus.

Amygdala

Human aggression can be explained in terms of biological structures, for example, the role of brain mechanisms and hormones. The limbic system and neurochemicals such as testosterone and serotonin are also thought to be important.

Illustrative background for AmygdalaIllustrative background for Amygdala ?? "content

Amygdala

  • The most important of these structures (in the limbic system) is the amygdala.
  • This determines how both humans and non-human animals behave in response to environmental threats and challenges.
  • The reactivity of the amygdala is proven to be an important predictor of aggressive behaviour.
Illustrative background for The Ultimatum GameIllustrative background for The Ultimatum Game ?? "content

The Ultimatum Game

  • Gospic et al. (2011) used a well-established laboratory method of assessing aggressive behaviour called the Ultimatum Game that featured two players.
  • In the Ultimatum Game, the proposer offers to split money in a certain way with the responder. If the responder accepts, the money is split as proposed. But if the responder rejects the offer, both receive nothing.
Illustrative background for __Gospic et al. (2011)__Illustrative background for __Gospic et al. (2011)__ ?? "content

Gospic et al. (2011)

  • Participants in this study played as responders while having their brain scanned by fMRI, which highlights activity in different areas of the brain.
  • The researchers reported that when responders rejected unfair offers the scans revealed a fast and heightened response by the amygdala.
Illustrative background for __Gospic et al. (2011)__ resultsIllustrative background for __Gospic et al. (2011)__ results ?? "content

Gospic et al. (2011) results

  • Gospic et al. also found that if a benzodiazepine drug (which reduces arousal of the autonomic nervous system) was taken before the game it had two effects on responses to unfair offers:
    • It halved the number of rejections, that is, it reduced aggression.
    • It decreased the activity of the amygdala.
  • This suggests an association between reactive (impulsive) aggression and amygdala activity.

Amygdala and the Orbitofrontal Cortex

The most important of the limbic system is the amygdala. The amygdala has a key role in humans and non-human animals in terms of how an organism behaves in response to environmental threats and challenges.

Illustrative background for Orbitofrontal cortexIllustrative background for Orbitofrontal cortex ?? "content

Orbitofrontal cortex

  • Recent studies indicate that the amygdala does not operate in isolation in determining aggression but appears to function in tandem with the orbitofrontal cortex (OFC), which is not part of the limbic system.
  • The OFC is thought to be involved in self-control, impulse regulation and inhibition of aggressive behaviour.
Illustrative background for __Coccaro et al. (2007)__ Illustrative background for __Coccaro et al. (2007)__  ?? "content

Coccaro et al. (2007)

  • Coccaro et al. (2007) found that patients with psychiatric disorders that feature aggression had reduced activity in the OFC.
  • This has been found to disrupt impulse control function and consequentially lead to increased aggression.
Illustrative background for Amygdala and OFCIllustrative background for Amygdala and OFC ?? "content

Amygdala and OFC

  • Combined with findings from Gospic et al. (2011), this indicates that the regulation of aggression is highly complex and involves at least three structures in the brain:
    • The amygdala.
    • The OFC.
    • The connection between the two.

Jump to other topics

1Social Influence

2Memory

3Attachment

4Psychopathology

5Approaches in Psychology

6Biopsychology

7Research Methods

8Issues & Debates in Psychology (A2 only)

9Option 1: Relationships (A2 only)

10Option 1: Gender (A2 only)

11Option 1: Cognition & Development (A2 only)

12Option 2: Schizophrenia (A2 only)

13Option 2: Eating Behaviour (A2 only)

14Option 2: Stress (A2 only)

15Option 3: Aggression (A2 only)

16Option 3: Forensic Psychology (A2 only)

17Option 3: Addiction (A2 only)

Go student ad image

Unlock your full potential with GoStudent tutoring

  • Affordable 1:1 tutoring from the comfort of your home

  • Tutors are matched to your specific learning needs

  • 30+ school subjects covered

Book a free trial lesson