Chapter 4 - Schizophrenia and Psychosis

Paralytic Dementia Behavioural & Neurological Symptoms

Delusions

Grandiosity

Euphoria

Poor Judgement

Argyll-Robertson pupil

Syndrome Definition

Clinically significant disturbance cognitively, emotionally or behaviourally.

Psychosis

Hallucinations or delusions and the person doesnt feel anything is wrong with them

Schizophrenia Positive Symptoms

Delusions

Hallucinations

Disorgonised Thinking

Schizophrenia Negative Symptoms

Alogia

Affective Blunting

Asociality

Anhodenia

Avolition

Negative versus Positive Symptoms

Negative symptoms are a deficit and take away from an experience; positive symptoms add to an experience. 

Explain the process of dopamine production

A reuptake pump transports tyrosine into the cell, and a two-step enzymatic process occurs to make dopamine. VMAT then moves dopamine into vesicles for dopamine to fuse and move into the synaptic cleft. 

Explain dopamine termination

MOA A or B re-packages dopamine into vesicles, and COMT is an enzyme that can inactivate dopamine. 

What does the D2 receptor do?

This autoreceptor will tell the presynaptic neuron to stop sending dopamine into the synaptic cleft. 

What are the four dopamine pathways?

Mesolimbic

Mesocortical

Nigrostriatal

Tuberoinfundibular

What is pathway b? 

Mesolimbic pathways from the VTA → nucleus accumbeans

What is pathway c?

Mesocortial pathway from VTA → frontal cortex (DLPFC and VMPFC)

What is pathway a?

Nigrostriatal pathway

What is pathway d?

Tuberoinfundibular pathway

Explain the Mesolimbic Dopamine Hypothesis of Positive Symptoms of Schizophrenia

Too much activation of dopamine on this pathway is lead to show increased posiitve symptoms of schizophrenia

Explain the Mesocortical pathway projections for dopamine and schizophrenia. 

This is from the VTA → frontal cortex, if there are difficulties in projections along this pathway, we can see negative symptoms of schizophrenia 

What do low levels in the Nigrostriatal pathway and Tuberoinfundibular pathway cause?

Galactorea and Parkinsons 

What is the main excitatory neurotransmitter in the brain?

Glutamate

What are the main receptors for glutamate in schizophrenia?

NMDA

AMPA

Kainate

Explain the NMDA recpetor.

Glutamate and an co-neurotransimtter are needed, but this isnt enough to open channel. Magneium (M++) is blocking and needs to be removed.

What causes the removal of M++ in the NMDA channel?

AMPA and Kainate receptors are activated, which depolarizes membranes and sends Na+ out, which removes Mg++

What does long term NMDA activation lead to?

Long term memeory processing and synaptogenisis

What can be a cause of NMDA hyperactivation?

This is what we believe causes the overactivation of dopamine and, therefore, positive symptoms. 

Explain this diagram

Pyramidal neurons communicate through GABAergic intermediate neurons. If the NMDA tone is altered, then the intermediate neuron can die, and this causes hyperactivation. This causes a hyperactive glutamate neuron, which leads to overstimulation of the dopamine pathway and, therefore, positive symptoms.