Conditions

Question 1

Schizophrenia

Answer 1

A neuropsychiatric condition that can be separated into type I and type II symptoms, which are not mutually exclusive

Question 2

Epilepsy

Answer 2

A disease that is characterised by a) two unprovoked seizures occurring over 24 hours apart or b) one unprovoked seizure with a high probability of recurrent seizures.

Question 3

Tonic-clonic seizures

Answer 3

A type of generalised seizure characterised by
- abrupt increase in muscle tone following by regular jerking movements of trunk and limbs
- impaired awareness during seizure
- post-ictal confusion

Question 4

Absence seizures

Answer 4

A type of generalised seizure characterised by
- abrupt onset and offset
- short duration (~10s)
- impaired awareness during seizure
- no post-ictal confusion

Question 5

Generalised seizures

Answer 5

• Originate at some point within and rapidly engage bilaterally distributed networks
• Can include cortical and subcortical structures but not necessarily the entire cortex

Question 6

Focal seizures

Answer 6

Originate within networks limited to one hemisphere
- May be discretely localised or more widely distributed
- Can have impaired awareness or full awareness

Question 7

Status epilepticus

Answer 7

Status epilepticus describes prolonged seizures that occur in tonic-clonic seizure and focal to bilateral tonic-clonic seizures
- T1: 5 minutes of continuous seizure activity
- T2: 30 minutes of seizure activity which can cause long term damage through glutaminergic excitotoxicity

Question 8

Proposed mechanism of epilepsy

Answer 8

Seizure activity is most commonly explained by excessive neuronal hyperexcitability which could arise from
- Increased synaptic excitation
- Reduced synaptic inhibition
- Increased intrinsic excitability

Question 9

Type I schizophrenia

Answer 9

Associated with acute schizophrenia

• delusions
• auditory hallucinations
• disorders of thought
• inappropriate behaviours (eg: stereotypy)

tends to relapse and remit

Question 10

Type II schizophrenia

Answer 10

Associated with chronic schizophrenia - individuals generally progress from type I to type II
- Social withdrawal
- apathy
- cognitive impairment
- poverty of mood and speech

Question 11

Dopamine hypothesis of schizophrenia (For, Against)

Answer 11

The dopamine hypothesis posits that psychosis is a result of excess dopamine
+ drugs that increase dopamine can induce psychosis (meth)
+ drugs that block dopamine receptors can treat psychosis
- some anti-psychotic drugs do not block DA receptors
- other neurochemical changes occur such as NMDA
- many patients refractory

Question 12

tardive dyskinesia

Answer 12

involuntary movements that arise from long term treatment with D2 antagonists
- likely resulting from a compensatory mechanism whereby dopamine receptors are upregulated

Question 13

Alzheimers Disease

Answer 13

A debilitating neurodegenerative disease characterised by
1. Neuronal degeneration
2. Amyloid plaque formation
3. Neurofibrillary tangles
+ death of cholinergic neurons in the nucleus basalis

Question 14

Parkinson’s disease

Answer 14

A disorder of the basal ganglia characterised by progressive death of dopaminergic neurons in the SNpc and the formation of lewy bodies, which are aggregates of a-synuclein in the cytoplasm of dopaminergic cells

Question 15

Symptoms of Parkinson’s disease

Answer 15

Bradykinesia, akinesia, postural instability, rigidity, resting tremor

Question 16

Effect of parkinson’s disease on the striatum

Answer 16

Normally in the dorsal striatum dopamine acts to modulate the response of GABAergic medium spiny neurons to glutaminergic input from the cortex.

The loss of dopamine in the basal ganglia input nuclei results in an imbalance between the inhibitory functions of dopamine and excitatory effects of acetylcholine on mAChRs of medium spiny neurons.

Question 17

What is MPTP?

Answer 17

MPTP is a biproduct of ‘synthetic heroin’ synthesised in the USA in the 1980s. It is selectively up taken by dopaminergic cells of the SNpc, where it undergoes metabolism via MAO b into MPP+. MPP+ interferes with mitochondrial metabolism, resulting in cell death and marked parkinsonian symptoms.

Question 18

Monoamine hypothesis of uni-polar depression

Answer 18

The monoamine hypothesis of unipolar depression states that depression is due to a deficiency of monoamine neurotransmitters (NA, DA, 5HT)
- Some psychiatrists believe different deficiencies lead to different forms of depression
- Most anti-depressants act on NA or 5HT neurotransmission, however most of these develop clinical effects slowly, despite fairly rapid neuropharmacological action
+ Serotonin response is repressed in depressed patients
+ PET scans show decreased serotonin levels