Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Limbic System

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now
Limbic System

Papez suggested in 1937 that the connecting circuit of the hippocampus and the limbic lobe were responsible for emotion (named the Papez Circuit).

MacLean later expanded this idea and redefined it as the limbic system. It was assumed that the processing of information is a hierarchical system: Information is received and processed first by the lower elements of the limbic system (the lower parts of the limbic system). Then the higher cognitive elements of the limbic system process the information to enable a sufficient response.

Below, we can see the limbic system diagram outlining the limbic system structures and how it has developed:

Limbic System Diagram StudySmarter Neural systems proposed to process emotion, Barger et al., Evidence for evolutionary specialisation in human limbic structures, 2014

Overall, the limbic system functions can be seen as the reactionary system to a perceived threat within the environment. Initially, it was associated with smell, but it has been highly linked with the autonomic nervous system (ANS) and the endocrine system after much research.

Limbic system structures

The limbic system structures comprise of the following subcortical areas of the brain, amongst others:

  • The hypothalamus is important in regulating the autonomic nervous system (ANS), regulating emotional responses. It is integral to maintaining homeostasis in the body and regulates hormones such as testosterone. It is the overseer of other brain regions, such as the pituitary gland. Damage here can cause inappropriate responses to perceived threats.

  • The hippocampus is involved in forming long-term memories and learning and spatial awareness and navigation. Neurogenesis (turning stem cells into nerve cells) occurs here. Damage here can severely impair your memory.

  • Amygdala is the emotional centre of the brain that processes fear-inducing and threatening stimuli and how they are linked/associated with forming new memories. It integrates emotions with motivational behaviours. Damage here can lead to more aggressive behaviours, as there’s a loss of control over your emotions (the brain’s emotional centre is important in emotions, it seems!)

  • Cingulate Gyrus: Although not wholly part of the limbic system (part of the cingulate cortex), it is closely linked and integrated and is vital in regulating aggression, emotional responses to pain, communication and maternal bonding, amongst other functions. The anterior cingulate gyrus is linked to Broca’s and Wernicke’s areas (involved in language comprehension and production). It is thought to aid the vocalisation of emotional responses.

Limbic System Location StudySmarterLimbic system location, Wikimedia Commons

The amygdala

The amygdala is essential when it comes to aggression, as it plays a vital role in how humans respond to the environment (as well as non-humans), including potential threats and hazards. It is also involved with how we process events linked to fear.

As a result, when the amygdala reacts or activates in response to a stimulus, it is usually a good predictor of any following aggressive behaviour that may occur afterwards.

Amygdala attaches significance to sensory information.

For example:

The fight or flight response: This response starts in the amygdala and is the first point of action in response to a potential threat. It sends a signal to the ANS so the body can react appropriately (through releasing adrenaline and noradrenaline).

The emotional centre of the brain: The amygdala is the emotional centre of the brain. It stands to reason that, with its association with aggression, the amygdala plays a vital role in how aggression is mediated and curated in the individual.

The hippocampus

The hippocampus is involved in memory and spatial awareness. Boccardi et al. (2010) found that prisoners with a history of violent offences (aggressive behaviours) had abnormal hippocampal defects that affected autonomic modulation and abnormal fear-conditioning.

Damage and disorders

When damage to the limbic system structures occurs, several disorders can develop, depending on the specific areas of damage. Here is an overview of the potential disorders that can come about as a result of damage:

  • Depression.

  • Anxiety.

  • Schizophrenia.

  • Bipolar.

  • Anger management disorders.

  • Parkinson’s disease.

  • Post-traumatic stress disorder (PTSD).

  • Memory disorders (storage, forming new memories).

As we can see, a wide range of effects can occur when this integral system is damaged.

Evaluation of the role of the limbic system in aggression

The limbic system has been linked to aggression in the following ways:

  • Kluver and Bucy (1939) removed the core areas of the limbic system in rhesus monkeys. Monkeys then went on to have issues and complete absences of responses with their emotions and motor functions when researchers showed them certain stimuli (specifically, stimuli meant to induce fear and anger), and their vocal functions.

    They also lost an understanding of their places in social hierarchies and were more aggressive to try and gain dominance even when it was inappropriate/ill-advised. However, one thing to remember is that although this study shows the importance of the limbic system in affecting emotions, particularly aggression, we can not conclusively say this is comparable or applicable to humans. We deal with aggression differently (socially and culturally, as well as mediation tactics) to rhesus monkeys.

  • Groves and Schelsinger (1982) surgically removed the amygdala to reduce aggression in violent individuals. However, upon removal, individuals were reported to have lost their sense of emotion altogether. This finding suggests that the amygdala is involved with aggression and the emotion regulation is not a direct cause.

  • Gospic et al. (2011): In this study, two participants, the proposer (P) and the responder (R), played the Ultimatum Game. In this game, the proposer offers to split money either fairly or unfairly to the responder. If accepted, the money is divided as suggested. If rejected, both parties receive nothing.

    • They had their brains scanned by an MRI during the game, which found a heightened amygdala response to rejected, unfair offers, more noticeably in males than females.

    • If the participants were given anti-anxiety drugs beforehand, the amygdala had a decreased response, and unfair offers were less rejected. Overall, this suggests the amygdala plays an important role in processing and mediating emotional behaviour, particularly aggression.

  • Phineas Gage: In the case of Phineas Gage, he suffered extreme frontal lobe damage after an accident occurred whilst he was working. A metal rod went through his skull and damaged most of his frontal lobe, affecting his prefrontal cortex. The prefrontal cortex is linked to the regulation of behaviours.Limbic System Phineas Gage StudySmarterMetal rod going through Phineas Gage’s skull, Wikimedia CommonsAfter the accident, despite surviving such an injury, Phineas lived for another 12 years. However, his friends noted he was more aggressive afterwards. With the damage, his prefrontal cortex could no longer regulate his behaviours and inhibit the amygdala, so he had an unjustified and unregulated response to what he perceived as threatening situations.

Limbic System Phineas Gage portrait StudySmarterPhineas Gage portrait after his brain injury, Wikimedia Commons

  • Chang and Gean (2019) found that stress in socially isolated mice activates the ventral hippocampus (vHip) neurones, which induces attack-like behaviour (aggression). These neurones, which project into the ventromedial hippocampus, induce aggressive behaviour and can be inhibited to reduce it. This finding suggests that the above systems are involved in aggression overall.

However, issues exist in that:

  • Links are only correlational: Research suggests there’s a link. However, both studies mentioned above only show a correlational link between aggression and the limbic system. It is not a direct cause, as seen in the case of Groves and Schlesinger. Similarly, in the UG study, the amygdala only showed a faster, increased activation. It does not mean that aggression is coming from the amygdala directly, only that it is linked.

  • Cause aggression or abnormalities?: The abnormalities in the limbic system may cause increased aggression. However, increased aggression may also cause abnormalities within the limbic system. There’s no significant evidence to suggest either interpretation is correct.

  • Beta bias: Multiple studies supporting the role of the limbic system, and in particular, the amygdala, have issues with beta bias (they generalise the study, which was performed on one sex, to apply to both sexes).

  • Wong et al. (1997): In this study, 20 repetitive violent offenders (RVOs) were compared to 19 non-repetitive violent offenders (NRVOs) from a maximum-security mental hospital. There were asymmetric gyral patterns at the temporoparietal region (essentially, different sized areas) that were particularly common in RVOs and absent in NRVOs. Yet, this study cannot be generalised to both males and females, as it’s a small sample size and was only conducted on men.


Limbic System - Key takeaways

  • The limbic system includes the amygdala, the hippocampus, the hypothalamus, and the cingulate gyrus.
  • The amygdala is the brain’s emotional centre and is responsible for the initial fight or flight response. It is involved in how humans process events linked to fear.
  • The amygdala is usually a good predictor of any following aggressive behaviour after a threatening stimulus is encountered.
  • The limbic system is linked to aggression, as multiple studies show if it is damaged or even removed, aggression usually increases. It also had an increased response to unfair situations. Removal of these systems can affect emotional responses, including motor and vocal functions/reactions.
  • However, studies have issues with beta bias, and the link is only correlational. We do not know if abnormalities in the limbic system are the result of increased aggression or if increased aggression is the result of abnormalities. If they are conducted on animals, they are not always applicable to humans.

Frequently Asked Questions about Limbic System

Papez suggested in 1937 that the connecting circuit of the hippocampus and the limbic lobe were responsible for emotion (named the Papez Circuit). MacLean later expanded this idea and redefined it as the limbic system.

Overall, the limbic system functions can be seen as the reactionary system to a perceived threat within the environment. Initially, it was associated with smell, but it has been highly linked with the autonomic nervous system (ANS) and the endocrine system after much research.

The limbic system is located below the cerebral cortex and above the brainstem in the brain.

There are many different causes for aggression and violence, and it is subjective (dependent on the person). However, the reasons behind an aggressive response can be linked to the neural mechanisms and the hormonal mechanisms in the brain.

The limbic system is involved in our behavioural and emotional responses, such as fight or flight responses.

The limbic system is located in the brain, and 

its structures comprise of the following subcortical areas of the brain, amongst others:

hypothalamus, hippocampus, amygdala, and cingulate gyrus.

Final Limbic System Quiz

Question

Who first proposed the limbic circuit?

Show answer

Answer

Papez, in 1937.

Show question

Question

How does the limbic system process information?

Show answer

Answer

It processes it hierarchically.

Show question

Question

What are the main components of the limbic system?

Show answer

Answer

The amygdala, the hippocampus, the hypothalamus, and the cingulate gyrus. (There are more components, but these are important for the exam!)

Show question

Question

What are the functions of the hippocampus?

Show answer

Answer

It is involved in the formation of long-term memories and learning. It is also involved in spatial awareness and navigation.

Show question

Question

What are the functions of the hypothalamus?

Show answer

Answer

It is crucial in regulating the autonomic nervous system (ANS), which regulates emotional responses. Damage here can cause inappropriate responses to perceived threats.

Show question

Question

What are the functions of the amygdala?

Show answer

Answer

It is the emotional centre of the brain, processing fear-inducing and threatening stimuli and how they are linked/associated with memory. It integrates emotions with motivational behaviours.

Show question

Question

What are the functions of the cingulate gyrus?

Show answer

Answer

Regulating aggression, emotional responses to pain, communication and maternal bonding, amongst other functions.

Show question

Question

What response starts in the amygdala?

Show answer

Answer

The fight or flight response.

Show question

Question

What is the amygdala, if stimulated, a good predictor of?

Show answer

Answer

Aggressive behaviours.

Show question

Question

What did Groves and Schlesinger find in their study?

Show answer

Answer

In this study, the amygdala was surgically removed to reduce aggression in violent individuals. However, it affects emotion overall and suggests the amygdala is linked to aggression but is not the cause.

Show question

Question

What did Gospic et al. find in their study?

Show answer

Answer

In the ultimatum game, there was a heightened response by the amygdala in response to rejected, unfair offers, more noticeably in males than females.

Show question

Question

How is the link between the limbic system and aggression only correlational?

Show answer

Answer

The research suggests there’s an association between the two. However, the studies only show a correlational link between aggression and the limbic system. It is not a direct cause.

Show question

Question

Abnormalities in the limbic system are caused by aggression, true or false?

Show answer

Answer

False. It cannot be proven that the abnormalities cause or result from aggression.

Show question

Question

What problems did Wong et al. have in their study?

Show answer

Answer

Issues with beta bias. Although there were structural differences in the aggressive, reoffending inmates, they could not apply it to females, as the study was a small sample size of males.

Show question

Question

How does the prefrontal cortex affect the amygdala?

Show answer

Answer

It inhibits it to help regulate aggression.

Show question

60%

of the users don't pass the Limbic System quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Just Signed up?

Yes
No, I'll do it now

Sign up to highlight and take notes. It’s 100% free.