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History

  • Darwin 1872
    • Book: expression of emotions in man and animals
    • Had pictures following emotions and expressions across different animal species and humans
    • Very similar continuity of emotions that you see in other animals - emotions seem to arise from a very basic part of the human brain (can detect similar emotions in other animals)
  • Papez circuit
    • Emotional stimulus --> thinking pathway (processed by sensory cortex etc for conscious control) AND ALSO to hypothalamus; combines information from the cingulate cortex and passes through the hippocampus, back to the hypothalamus that controls the bodily stress response
  • MacLean's limbic system (hippocampus)
    • Inputs from the auditory and visual cortex; and this information is combined in the cingulate cortex; this part of the brain also is involved in creating emotions
  • In addition to these ancient parts of the brain, there are important control mechanisms from the dorsomedial and orbital ventromedial and prefrontal cortexes
    • In man we see the development of the prefrontal cortex with rich connections back to ancient structures, making us able to control emotions.
      • E.g. the toddler tantrum is replaced with the capacity to reason with the child (you have CONTROL over your emotions)

Anger

  • A strong feeling that makes you want to hurt someone or be unpleasant because something unfair or hurtful has happened
  • Some people find it very hard to control their anger
  • Neurobiology - serotonin
    • Disruption of the serotonin system linked to aggression and violence. CSF levels of 5-HIAA reflects presynaptic levels of serotonin. Reduced in aggressive psychiatric patients, violent men, and victims of suicide by violent means, impulsive firesetters and impulsive violent offenders.
    • CSF5 - IAA reflects presynaptic serotonin
      • Shown to be low in violent men, prisoners, violent suicide cases, impulsive firestarters, violent offenders, aggressive psychiatric patients
      • Ie: aggressive people who can’t control emotions or regulate anger
        • Case: Bella, affective instability
          • ADHD
          • Anger, tantrums; particularly in the late afternoon. Remembers the episodes later but feels no remorse.
          • Impulsivity, destructive
          • Episodic aggressive behaviour – suggestive of bipolar spectrum disorder
          • Bipolar is hard to diagnose in children because cognitive control mechanisms are still developing
            • Poor social skills, but charismatic following
            • Current: Treatment with Ritalin (focuses attention and helps concentration). Indication: Also mood stabilisers (sodium valproate; also used for epilepsy. Help control the disruption of the serotonergic system that are causing these rage cases occurring)
              • Further treatment: CBT to control aggression + alternative outlet for anger (martial arts?)
                • CBT - teaching the patient how to control their own feelings, by teaching them some strategies. Also need to recognise the early warning signs (e.g. increased heart rate, and a sense of tension) - need to get prefrontal cortex working to help her modulate physiological changes that are happening that are assisting the uncontrollable rage
          • Some of these fluctuations in mood are normal for children, as part of development. We need to be careful diagnosing bipolar disorder in children.
  • Genetics:
    • Anger scores have been linked to:
      • DARPP32 genotypes
        • Phosphoprotein related to dopaminergic systems (another one of the monoamines)
      • Left amygdala volume (grey matter)

Impulsivity

  • Failure to resist impulse/drive/temptation
    • Result: rapid, unplanned reactions to internal and external stimuli
    • Inability to delay reward, think before acting; drive or temptation, resulting in rapid, unplanned reactions to internal or external stimuli
      • Impulsive people choose small immediate rewards instead of larger delayed rewards
    • Impaired executive function
  • Linked with novelty/sensation seeking behaviour
    • A personality style, linked with MAO (monoamine oxidase) that breaks down catecholamine NTs
  • Case: Alex, impulsive, ADHD history
    • Family history of alcohol abuse
    • Does things without thinking (e.g. jumping into water while intoxicated, breaking legs)
      • Responds to challenges and doesn’t think about consequences
    • Treatment:
      • SSRI – serotonin is implicated in impulsive tendencies (but the issue here is one of maturity, and trying to develop prefrontal cortex connections to reduce sensation-seeking behaviour, and education about controlling moods; also maturity needs to be developed in terms of not putting himself in situations that he is at risk e.g. not drinking on a bridge at night)
      • CBT:
        • Strategies to stop and think about the consequences of actions
        • Alcohol – disinhibitor, impairs judgement
          • Motivational interviewing to make aware of alcohol effects + family hx



Regions of the brain

  • fMRI (look at bloodflow in the brain according to tasks) with monetary incentive task
    • if performance (speed/accuracy) is better than previously, earn money
    • people who do better are those with impulsive reaction styles
      • correlation with ventral striatum and orbital frontal cortex – impulsivity
  • Areas correspond to different emotions/actions:
    • Orbital frontal cortex, ventromedial prefrontal cortex–impulsivity
    • Dorsolateral prefrontal cortex – executive function, goal setting, ordering of actions
    • Amygdala–facialemotionrecognition,anger management
    • Anterior cingulate cortex–control of attention and inhibiting behaviours
  • A = ventromedial cortex; ventrolateral cortex
  • B =
  • C = amygdala (coronal view)
  • D = cingulate cortex (?)

(listen to mp3)

Social exclusion experiment

  • Cyber ball - Kip Williams
  • Dorsal anterior cingulate cortex activity, in a fMRI
  • Participant plays a computer game while in a scanner (told that they're playing with other characters, but the other characters are computer people). They throw a ball to each other. Computer program after a while starts to exclude the participant (it's an experimental way of testing social exclusion). Activation in dorsal part of anterior cingulate cortex is associated with MAO alleles.
    • With increased trait aggression, greater degree of activation

Sensation seeking

  • Choose whether you like impulsive or conservative behaviours
  • Decreased platelet MAO related to sensation seeking; particularly in males (higher levels of sensation seeking are seen in males)

Phineas Gage

  • Model citizen, good worker, family with children
  • Working with tamping rod, uncontrolled explosion forced it through his head
  • Recovered and didn't die. After it there were no obvious neurologica or physical conditions, but his personality changed
    • Destroyed some of the orbitofrontal cortex
      • personality changed. Fitful, irreverent, indulging at times in the grossest profanity which was not previously his custom, manifesting but little deference for his fellows. Went from being sober, sensible, hard-worker to being impulsive, out of control and has reverted to a childhood pattern of doing everything thinking about it.
      • Impulsive, aggressive
      • Forgot about work, family fell apart, turned to alcohol
  • Ie. prefrontal brain (orbitofrontal cortex) systems are important in the regulating of impulsivity/aggression
  • But later on he did regain some of his sober personality
    • I.e. there is some plasticity in the brain. The orbitofrontal cortex was removed from controlling the amygdala etc, but new pathways were developed over time that enabled to restoration of that function. It is possible for other parts of the brain to take up those functions (also it was important that it was a unilateral injury - damage to only one hemisphere - some restoration of prefrontal control mechanisms).
    • Whilst it is important to recognise there are circuits we can identify that regulate impulsivity, there are many ways the brain can rewire itself to control these emotions. Therefore we have a neurobiological background for CBT.
    • Anterior cingulate gets larger during CBT to help people learn to cope with chronic fatigue syndrome.
  • The brain is not a fixed hard-wired structure that shows only degeneration: neurogenesis continues to take place throughout life and there is plasticity of the brain and this opinion provides a background for CBT etc
    • In addition, note there is a range of medications that have a role to play, but in all these medications you have to think about risk-benefit
      • Note the negative effects of weight gain (affects social stigma and CVD)
  • You need careful judgement to know what to do in these circumstances

Important factors

  • Genotype leading to multifactorial brain elements, and chemical elements
    • Thus individual variation