Week 9 (Kluver-Bucy, Alzheimer's, Korsakoff's)

Kluver-Bucy Syndrome

Damage to the medial temporal lobe or Amygdala can lead to Kluver-Bucy syndrome.

  • Patients with this syndrome show signs of

    • Hyperphagia (overeating)

    • Hypersexuality

    • Visual agnosia

    • Fearlessness

    • Trouble recognizing objects or faces

    • Cannot tell or learn if something should be feared or not

    • Can be fatal

Alzheimer’s Disease

Onset is usually in older age

  • affects 5% of those aged 65-74

Patients often have better procedural memory than declarative memory

  • major impairment of episodic memory

Memory deficits likely result from malfunctioning neurons as well as loss of neurons

Disease is likely linked to genes on chromosome 21

  • People with down syndrome have 3 copies of this chromosome

  • They often get Alzheimer’s if they survive into middle age

Associated with early-onset Alzheimer’s disease and amyloid plaques

People often show larger ventricles due to shrunken cortex

Neurodegenerative 

  • severity progresses with time

  • Memory loss

  • Confusion

  • Depression

  • Restlessness

  • Hallucinations

  • Delusions

  • Sleepiness

  • Loss of appetite

There are two hallmarks of Alzheimer’s disease

Amyloid Plaques

  • Scar tissue from degenerating neurons

  • It accumulated inside and outside the neurons'

  • Damaged axons and dendrites decrease synaptic input and plasticity

Neurofibrillary Tangles

  • Tangles of tau proteins in the cytoplasm

  • Caused by phosphate groups that attach to tau proteins

  • Cannot bind to usual targets with axons

Treatment

There is no cure for Alzheimer’s yet

Most common treatment is to give drugs that target acetylcholine

  • stimulate receptors or prolong acetylcholine

  • Increases mental arousal since alertness usually decreases with severity

Treatment is often ineffective

  • Possibly because timing is usually recognized too late

Korsakoff’s Syndrome'

Associated with thiamine (vitamin B1) deficiency

Common in people with severe alcohol use

  • Prolonged thiamine deficiency can lead to loss or shrinkage of neurons in the brain

  • Particularly the dorsomedial thalamus

  • The mammillary bodies are also often damaged

    • part of the limbic system

  • Ventricles are enlarged

  • Symptoms

    • Can mirror cortex damage

      • Sensory/motor issues

      • Confusion

      • Personality changes

    • Can also overlap with hippocampal damage

      • Major impairment of episodic memory

    • Distinct symptom

      • Confabulation

      • Fill in memory gaps with guesses