Limbic system

• What does the limbic system control?

  Feeding

  Forgetting (memory)

  Fighting (emotional response)

  Family (sexual reproduction and maternal instincts)

  Fornicating (sexual behaviour)
• Thalamus:

  • receives sensory and motor "signals" and delivers them to the cerebral cortex
  • damage to the thalamus (stroke) can cause hyperalgesia and allodynia
• Hypothalamus: homeostasis, hunger/satiety
• Ghrelin: produced by cells in the gastrointestinal tract --> causes hunger when increased

  Leptin: produced by adipose tissue cells --> induces satiety when increased

  G for gaining weight

  L for loosing weight
• Amygdala: processes emotions --> proper emotional response.

  • fear
  • memory consolidation and use of implicit memory
• AMYGDALA HIJACK:

  • life or death situation/ high emotion
  • no processing by the higher cortex whatsoever
• Alzheimer's causes bilateral lesions of the amygdala, which results in:

  • amnesia, visual agnosia (difficulty recognising objects)
  • lack of control over one's behaviour
• Alzheimer's also causes damages to HIPPOCAMPUS, which causes:

  • anterograde amnesia (inability to make new long-term memories) as hippocampus is responsible for memory consolidation from short-term one to long-term one
  • lack of spatial orientation
  • ! hippocampus is a site of neurogenesis
• Mammillary bodies:

  • recollective memory --> helps to create appropriate behavioural reactions
  • DAMAGE causes both retrograde and anterograde amnesia
• Korsakoff syndrome -- degeneration of mammillary bodies caused by VITAMIN B12 deficiency

  • blinking rapidly
  • loss of coordination
  • no memories
• Language - temporal lobe

  Two areas: Broca's and Wernicke's

  Broca's aphasia --> inability to form coherent sentences --> gibberish

  Wernicke's aphasia --> impaired speech --> difficulty to form words