Module 10: Brain-Based Amnesia and Alzheimer's Disease

Amnesia

• Describes any memory impairment that extends beyond your typical forgetting

• Also refers to deficits caused by damage

Hallmark of many amnesiac disroders

Inability to form episodic memory

Amnesia can be mimicked by

Benzodiazepines

Amnesia can be induced by

Electroconvulsive Shock Therapy (ECT), which is sometimes used to treat patients with severe clinical depression

Anterograde amnesia

Inability to form new memories after brain damage

Associated brain regions for anterograde amnesia

• Hippocampus (learning, memory)

• Mammillary bodies (consolidation)

• Fornix (information pathway from hippocampus)

Amnesic syndrome

Common set of deficits coinciding with anterograde amnesia

Associated brain regions for anterograde amnesia damage leads to

Amnesic syndrome

Can those with anterograde amnesia form new memory implicitly?

Yes

How is anterograde amnesiac’s implicit memory tested?

Repetition priming

3 “coping” strategies used in memory conversations

• Memory importation

• Memory appropriation

• Memory compensation

Memory importation

An event that occured prior to the brain damage is being describes as a new memory, transplanting the memory into a different part of one’s memory timline

Memory appropriation

Describing someone else’s recollection as a personal memory

Memory compensation

When asked about a past memory, they discuss the struggles or memory related issues rather than answering the question

Retrograde amnesia

Inability to retrieve old memories after brain damage; usually does not mean all memory is gone

Ribot’s law

New memories are more like to be impacted (gone) than older memories; leads some people to believe that retrograde amnesia occurs because the damaging incident interrupts memory consolidation

Associated brain regions for retrograde amnesia

• Hippocampus (memory retrieval)

• Temporal lobe (retrieval network)

• Pre-frontal cortex (directed memory search)

Korsakoff’s disease usually occurs with

Older adults with history of persistent alcohol abuse ; deficiency with B1 or thiamine due to brain damage over time

Korsakoff’s Disease

• Retrograde and anterograde amnesia

• They are unaware of their deficits

  • Makes treatment difficult

• Confabulation (“honest lying”)

  • Generating false memories while believing them to be true

• Poor metamemory

Korsakoff’s disease brain region

Diencephalon (information routing)

Frontal syndrome

• Caused by damage to the brain’s frontal lobes

• Associated symptoms

  • Retrograde amnesia

  • Confabulation

  • Agnosia

• Other impacts

  • Source monitoring

  • Temporal order of past events

  • Planning, problem solving, language, emotion, personality

Agnosia

Difficult recognizing objects, people, smells, etc.

Transient global amnesia

• Sudden onset of amnesia

  • Anterograde → severe

  • Retrograde → moderate

• Very short lived, only temporary

• Can be brought on by rigorous exercise or physical stress (elevated heart rate); history of migraines

  • Exact causes not clear

• May ask repeated questions because they can’t encode

• Other aspects of memory stay intact

Short-term (working) memory amnesia

• Deficits in working memory

• Important role of frontal and parietal lobes

Capgras Syndrome

• Patient believes that close friends/family members have been “duplicated” ; they are imposters or robots

• Results from breakdown or damage to connections between areas of temporal lobe and limbic system

  • Can result from psychiatric conditions or from physical trauma

  • Lack of emotional response to face = assumed duplicate

Reduplicative Paramnesia

• Patient believes that locations have been duplicated

• Breakdown or damage to areas in the parietal lobe and prefrontal cortex

6th leading cause of death

Alzheimer’s

Alzeheimer’s presentations

• Early: memory deficits (“my memory isn’t what it used to be)

• Middle: Amnesia and reduced language ability

• Late: Difficulties with motor movement and basic functioning

Brain-related contributors for alzheimers

• Amyloid plaques: gooey protein-based substance that mess with functioning →

• Neurofibrillary tangles: reduce functioning of axon in neurons and inhibit neuron communication, causing synaptic connections to deteriorate and die off

• Acetocholine production decreases

What can we do about alzheimers?

• No cure or preventative measures against it

• Treatments attempt to reduce likelihood of development and/or delay onset of symptoms

  • Lifelong engagement in challenging activities

  • Active social life

  • Healthy, low-cholesterol diet

  • Medication or magnetic stimulation once its been diagnosed

Memory intervention

• Focus on compensation

  • Alarm clocks

  • Notebooks

  • Smart phones

• Learning through implicit memory

  • Errorless learning

Errorless learning

• Person is guided through various repetitions of a procedural exercise

• For any errors made, they’re given immediate corrective feedback and they begin exercise again

• As they progress, memory cues are gradually removed until they no longer need the cue to complete the exercise correctly