Schzophrenia and Alzheimer's

Question 1

Define schizophrenia

Answer 1

A psychological disorder characterized by the presence of symptoms that includes delusions, hallucinations, disorganized speech, disorganized behavior, diminished emotional expression, and cognitive impairments.

Question 2

Name the positive symptoms of schz

Answer 2

Delusions and hallucinations (AKA pscyhotic symptoms)

Question 3

Define delusions

Answer 3

misrepresentations of reality

Question 4

Name and define the 3 types of delusions

Answer 4

• Of grandeur: believing we are someone we are not
  * Of persecution: believing that someone is out to hurt us
  * Paranoid delusions: over suspicious of others in the most non realistic ways (ex: aliens are watching)

Question 5

Define hallucinations; which type is most common in schz patients?

Answer 5

perceptions of sensory events that are not occurring in reality, can involve any of the senses
• Most common in schizophrenia are auditory

Question 6

Name positive symptoms of schz that are not considered psychotic

Answer 6

Disordered speech and behaviours

Question 7

Define the negative symptoms of schz and their 3 main categories

Answer 7

Diminished emotional expressions (AKA flat affect)
• Avolition (reduction in motivations to engage in activities)
• Anhedonia (inability to feel pleasure)
• Alogia (poverty of speech)

Question 8

Name the 3 main brain abnormalities associated with schz

Answer 8

• Enlargement of brain ventricles (not in all cases, not the cause of the disease)
  * Compresses the close brain regions, which impair their development and leads to symptoms
  
  • Gray matter loss
    
    • Temporal, parietal and some part of PFC mostly
  • Lower than normal functioning of prefrontal cortex (Wisconsin Card Sorting Test)

Question 9

Define the Wisconsin Card Sorting test; how do people with PFC damage do in this task?

Answer 9

Asked to sort a deck of cards by shape, color or symbols
• Then the rule changes
• PFC damage: difficulty to switch to a new pattern of sorting

Question 10

Define the hypofrontality theory of schz

Answer 10

idea that activity in the PFC is reduced in people with schizophrenia

Question 11

Define the dopamine hypothesis of schz

Answer 11

idea that a dysfunctional dopaminergic system is at the core of schizophrenia

Question 12

Define the 1st version of the dopamine hypothesis; what are the problems with this version?

Answer 12

1. Drugs that are effective against schizophrenia block dopamine receptors in the brain
   a. Also, drugs that increase dopamine levels can induce schizophrenic-like symptoms
   b. Problems: does not mention which brain areas affected, does not mention which symptoms affected

Question 13

Define the 2nd version of the dopamine hypothesis

Answer 13

2. Positive symptoms are due to excessive dopamine neurotransmission in the striatum, and negative due to lack of dopamine neurotransmission in the frontal lobes

Question 14

Define the 3rd version of the dopamine hypothesis

Answer 14

3. Many factors account for the dysfunction of dopaminergic neurotransmission in schizophrenic patients (therefore to hallucinations)
   a. Those dysfunctions happen in presynaptic neurons and not in D2 receptors
   b. Dopamine dysregulation is linked only to the psychotic symptoms
   c. Excessive dopamine release increases the salience of stimuli to the point where it becomes exaggerated, giving rise to hallucinations

Question 15

Define the aberrant salience hypothesis

Answer 15

c. Excessive dopamine release increases the salience of stimuli to the point where it becomes exaggerated, giving rise to hallucinations

Question 16

Define the NMDA-receptor-hypofunction hypothesis of schz, name 2 reasons why it might be valid

Answer 16

suggests that NMDA receptors are dysfunctional in people w schizophrenia
WHY? ->
• Drugs blocking NMDA receptors induce symptoms similar to schz
• Drugs that increase glutaminergic neurotransmission alleviate these symptoms

Question 17

Name the 4 theories that could explain auditory/verbal hallucinations in schz patients

Answer 17

1- Auditory and verbal hallucinations may be due to memories unrelated to present context appearing into consciousness without intention (memories fail to be suppressed by memory system)
• Due to altered connectivity between hippocampus, superior temporal gyrus (auditory cortex), Wernicke’s area, Broca’s area through the striatum - brain areas responsible for language memory and auditory processing
2- Hallucinations may be due to dysfunctioning in self-monitoring
• Perceiving internal speech as externally generated
Due to altered connectivity in frontal areas, anterior cingulate cortex, Broca’s area, and temporal areas (Wernicke’s)
3- Hallucinations due to hyperconnectivity between auditory areas of both hemispheres through corpus callosum
• Source: tinnitus (condition in which sound is perceived with no external stimulation) is due to this
4- Hallucinations may be cause by an alteration in the balance between bottom up sensory processing (perception are influenced by sensory perception) and top down mechanisms (when your perceptions are influenced by your own thoughts)

Question 18

Name the 2 phenomena affected by normal aging in the brain

Answer 18

1- Fluid intelligence: ability to think quickly and abstractly. It includes the capacity of working memory and processing speed.
○ Involves processing speed: speed at which info can be analyzed and at which mental tasks are performed
2- Crystallized intelligence: cognitive skills that depend on accumulated wisdom, knowledge, expertise and vocabulary

Question 19

Define Alzheimer’s disease

Answer 19

Degenerative brain disease characterized by the severe and progressive loss of memory and other thinking skills to the point where self-care is no longer possible

Question 20

Define the concept of the amyloid-hypothesis of AD

In which parts of the brain does it mainly occur?

Answer 20

the hypothesis that AD results from an accumulation of the peptide beta-amyloid, which forms plaques that cause synaptic dysfunction, inflammation, and neuronal death.
• This process is thought to occur mainly in parts of the brain related to memory (enthorinal cortex and hippocampus)

Question 21

Name 2 problems related with the amyloid hypothesis

Answer 21

• Medications developed to reduce amyloid in neurons have not been effective in treating AD
  
  • The progression of Alzheimer’s disease is more highly related to the effects of other changes than AB plaques formation (ex: inflammation)

Question 22

Explain the 1st step of AD

Answer 22

Step 1: mild cognitive impairment
• Short-term memory loss
• Medial Temporal lobe
• 7yrs

Question 23

Explain the 2nd step of AD

Answer 23

Step 2: Mild Alzheimer’s
• Reading problems, poor object recognition, poor direction sense
• Lateral/temporal/parietal lobes
2yrs

Question 24

Explain the 3rd step of AD

Answer 24

Step 3: Moderate Alzheimer’s
• Poor judgement, impulsivity, short attention
• Frontal lobe
2yrs

Question 25

Explain the 4th step of AD

Answer 25

Step 4: Severe Alzheimer’s
• Disease spreads to occipital lobe
• Visual problems
3yrs

Question 26

Define the tau hypothesis of AD

Answer 26

Tau Hypothesis of AD: A hypothesis based on the observation that the progression of Alzheimer’s disease is related more to the effects of changes in tau than to the formation of beta-amyloid plaques

Question 27

What is tau?

Answer 27

• Tau: microtubule protein

○ Makes the microtubules of the cells collapse and leads to communication problems between neurons

Question 28

Define the metabolism hypothesis of AD

Answer 28

hypothesis that AD and type-2 diabetes share common characteristics. People with type-2 diabetes have 1.5 times the risk of developing dementia compared to people without type-2 diabetes