neurological disorders 2

What is Parkinson's disease?

A progressive neurodegenerative disorder primarily affecting movement.

What are the four cardinal motor symptoms of Parkinson's disease?

Bradykinesia, resting tremor, rigidity, and postural instability.

What is bradykinesia?

Slowness of movement.

What is rigidity?

Increased muscle stiffness and resistance to passive movement.

What is postural instability?

Impaired balance and postural control.

What type of tremor is characteristic of Parkinson's disease?

A resting tremor.

Which neurotransmitter is most affected in Parkinson's disease?

Dopamine.

Which brain region undergoes degeneration in Parkinson's disease?

The substantia nigra pars compacta.

What is the substantia nigra?

A midbrain structure containing dopamine-producing neurons.

What happens to dopamine neurons in Parkinson's disease?

They progressively degenerate.

What is the primary consequence of dopamine neuron degeneration?

Reduced dopamine transmission in the basal ganglia.

Which structure receives dopamine projections from the substantia nigra?

The striatum.

What is the striatum?

A major input structure of the basal ganglia.

What is the role of the basal ganglia in movement?

Selection and initiation of appropriate movements.

Why does dopamine loss impair movement?

It disrupts normal basal ganglia function.

What are common non-motor symptoms of Parkinson's disease?

Depression, sleep disturbances, cognitive impairment, and autonomic dysfunction.

What pathological protein accumulates in Parkinson's disease?

Alpha-synuclein.

What are Lewy bodies?

Intracellular protein aggregates containing alpha-synuclein.

Where are Lewy bodies found?

Within neurons.

What is alpha-synuclein?

A neuronal protein associated with synaptic function.

What happens to alpha-synuclein in Parkinson's disease?

It aggregates and forms Lewy bodies.

What is the most effective symptomatic treatment for Parkinson's disease?

Levodopa (L-DOPA).

What is levodopa?

A precursor molecule that is converted into dopamine in the brain.

Why is dopamine itself not given as treatment?

It does not effectively cross the blood-brain barrier.

Why can levodopa cross the blood-brain barrier?

It uses amino acid transport systems.

What enzyme converts levodopa into dopamine?

DOPA decarboxylase.

What is often administered alongside levodopa?

A peripheral DOPA decarboxylase inhibitor.

Why are peripheral DOPA decarboxylase inhibitors given with levodopa?

To increase the amount reaching the brain and reduce side effects.

What is deep brain stimulation (DBS)?

A neurosurgical treatment involving electrical stimulation of specific brain regions.

Which disorder is commonly treated using DBS?

Parkinson's disease.

What is schizophrenia?

A severe psychiatric disorder involving disturbances in thought, perception, and behaviour.

What are positive symptoms of schizophrenia?

Symptoms that reflect an excess or distortion of normal function.

Give examples of positive symptoms of schizophrenia.

Hallucinations, delusions, and disorganised speech.

What are hallucinations?

Sensory perceptions occurring without external stimuli.

What are delusions?

Fixed false beliefs resistant to contrary evidence.

What are negative symptoms of schizophrenia?

Loss or reduction of normal functions.

Give examples of negative symptoms of schizophrenia.

Avolition, flattened affect, and social withdrawal.

What is avolition?

A reduction in motivation and goal-directed behaviour.

What is flattened affect?

A reduction in emotional expression.

What are cognitive symptoms of schizophrenia?

Impairments in attention, memory, and executive function.

What neurotransmitter hypothesis is most strongly associated with schizophrenia?

The dopamine hypothesis.

What does the dopamine hypothesis propose?

That excessive dopamine signalling contributes to schizophrenia symptoms.

Which dopamine pathway is most strongly linked to positive symptoms?

The mesolimbic pathway.

What is the mesolimbic dopamine pathway associated with?

Reward and motivation.

How is dopamine activity altered in the mesolimbic pathway in schizophrenia?

It is increased.

Which dopamine pathway is associated with cognitive and negative symptoms?

The mesocortical pathway.

How is dopamine activity altered in the mesocortical pathway in schizophrenia?

It is reduced.

What is the mesocortical pathway associated with?

Cognition and executive function.

What class of drugs is primarily used to treat schizophrenia?

Antipsychotic drugs.

What is the primary mechanism of most antipsychotic drugs?

Dopamine D2 receptor antagonism.

What is a D2 receptor?

A subtype of dopamine receptor.

How do antipsychotic drugs reduce positive symptoms?

By reducing dopamine signalling.

Give an example of a typical antipsychotic.

Haloperidol.

What is a major limitation of typical antipsychotics?

They can cause movement-related side effects.

Why can antipsychotics produce movement side effects?

They block dopamine signalling in motor pathways.

What are atypical antipsychotics?

Newer antipsychotic drugs with broader receptor actions.

Give an example of an atypical antipsychotic.

Clozapine.

How do atypical antipsychotics differ from typical antipsychotics?

They affect dopamine and serotonin systems.

Which neurotransmitter besides dopamine is implicated in schizophrenia?

Glutamate.

Which receptor has been implicated in schizophrenia through ketamine and PCP research?

The NMDA receptor.

Why are ketamine and PCP relevant to schizophrenia research?

They can induce schizophrenia-like symptoms.

What neurotransmitter receptor is blocked by ketamine?

The NMDA receptor.

What neurotransmitter receptor is blocked by PCP?

The NMDA receptor.

What is the glutamate hypothesis of schizophrenia?

The theory that reduced NMDA receptor function contributes to symptoms.

Which disorder is associated with dopamine neuron degeneration?

Parkinson's disease.

Which disorder is associated with excessive mesolimbic dopamine activity?

Schizophrenia.

Which disorder is associated with alpha-synuclein accumulation?

Parkinson's disease.

Which disorder is associated with hallucinations and delusions?

Schizophrenia.

Which disorder is treated with levodopa?

Parkinson's disease.

Which disorder is treated with antipsychotic drugs?

Schizophrenia.

Which neurotransmitter is deficient in Parkinson's disease?

Dopamine.

Which neurotransmitter pathway is hyperactive in schizophrenia according to the dopamine hypothesis?

The mesolimbic dopamine pathway.

What pathological structure is characteristic of Parkinson's disease?

Lewy bodies.

What pathological protein forms Lewy bodies?

Alpha-synuclein.

Which receptor is the main target of most antipsychotic drugs?

The dopamine D2 receptor.