Principles of Neuroscience Lecture 28 Disorders of the Nervous System I Flashcards
What are the categories of neurally related disease?
Mental disorder
Neurological disorder
Learning or developmental disorder
Drug addiction
How many people worldwide suffer from neurological disease?
450 million
Describe the difference between mental disorders and neurological disorders.
It is an old fashioned view that mental disorders have no organic basis, and are merely functional problems of the brain
Neurological disorders, however, have an organic basis that you can point to
What is the difference between psychiatry and neurology?
Neurology: looking at organic causes of disease
Psychiatry: diseases that are thought to be merely functional, no problem with the machinery
What are learning and developmental disorders?
These are due to injury to the developing nervous system in childhood
What are some examples of learning and developmental diseases?
Trisomy 21
Fragile X
Tay sachs
Neurotropic infections
What do mental disorders affect?
Cognition, emotion, behavioural control
Describe the characteristic onset of mental disorders
Usually early onset, with chronic recurrence throughout life
What is the aetiology of mental disorders?
Complex, however gender does play a role.
Genetics and environment plays a role
What are some significant examples of mental disorders?
Schizophrenia
Bipolar affective disorder
Major depressive disorder
Panic disorders
Describe the evolution of pharmacological treatment for mental disorders
In the 50’s they found that some drugs could affect mental disorders
Thus, there must be some organic basis to these mental disorders
Which drugs are effective against mental disorders? How do these work?
Benzodiazepines were especially effective, for example Valium (diazepam)
Describe what is significant about the treatment with drugs of schizophrenia
There are many different types of drugs
They lower the affinity the drug with D2, the higher the dose required for effective control. This is striking, because it says that there is a direct connection between binding of the drug and relief from the disorder
What are the major neurological diseases?
Epilepsy
Alzheimer’s
Multiple sclerosis
What is the aetiology of multiple sclerosis?
Unclear, however there is a profile for people who get this disease
Young, female, middle class, temperate climate
Eg. Jacqueline du pré
What is the pathophysiology of multiple sclerosis?
Myelin on the neurons is destroyed by an auto immune response
These neurons may be motor or sensory etc.
What are the clinical manifestations of multiple sclerosis?
Vision, sensation, movement, speech, cognition, balance are all affected
Depression
Muscle weakness
What is the pathophysiology of Alzheimer’s disease?
Extracellular deposits of amyloid protein plaques in the brain
Intracellular tangles of tau protein
Disruption of the neuronal cytoskeleton
- Deposition begins in the hippocampus, over many years, the hippocampus is destroyed.
- Inability to store new memories in the neocortex
- Spreads to the rest of the brain, distinctive pattern: median temporal lobe
What are the clinical manifestations of Alzheimer’s ?
Memory loss
Cognition and intellectual function are affected
What are the types of cytoskeleton?
Microtubule
Actin
Neurofilament
Differentiate between amyloid plaques and tau tangles
Amyloid plaque form outside the neurons
Tau tangles form inside cells when there has been amyloid plaque formation
What is the definition of epilepsy?
Two or more seizures
Ie. the seizures must be recurrent
How can epilepsy be detected?
EEG shows massive synchronous waves of brain activity
What is going on during a seizure?
Transient, hyper-synchronous, abnormal neuronal activity
What are the types of epilepsy?
- Idiopathic: genetic basis, childhood onset
- Secondary or symptomatic epilepsy: CNS injury or disorder
- Cryptogenic: no idea what causes it
What is the genetic basis for epilepsy?
There is a link between epilepsy and mutations in proteins that are related to neural excitability
Such as ion channels or neurotransmitter receptors
How could one ion channel affect neuronal firing?
This could cause an imbalance in the excitation of inhibition of a neurons, leading to hyper synchronous firing and convulsions
What treatments do we have for epilepsy?
Dilantin, Zonisamide, Epilim
We have drugs, but we don’t really know how they work
Most likely, they work to:
- enhance GABA
- block Na or Ca channels
What is the normal function of tau?
It is involved in the stability of the neuronal cytoskeleton
