NEURO Epilepsy and Neuroplasticity Flashcards
(11 cards)
What is epilepsy?
Chronic medical condition, temporary changes in electrical changes in function of brain, causing seizures, affecting awareness, movement and sensation.
Effects 0.5%- 1% population, mainly children and elderly.
Idiopathic disease (no one cause, e.g. brain injury, swelling of brain).
What are epilepsy symptoms dependant on?
Epilepsy type, areas of brain affected.
What are the different types of epilepsy?
Partial epilepsy, complex, partial seizures, generalized epilepsy.
What is partial epilepsy?
Experience simple partial seizures.
Localised to specific areas of brain (‘partial’). Effects= localised. Usually sensory and/or motor. E.g. localised jerking in right hand. Can progress to colonic movements i.e. jerks of entire right arm. Progression (Jacksonian March) up arm produced by epileptiform activity in motor cortex that controls the arm.
What are complex partial seizures?
In specific parts of the brain (‘partial’). Effects= complex + diverse. Called focal onset impaired awareness seizures. Associated with apparently ordered/ coordinated but inappropriate motor behaviour.
-e.g. running, chewing, buttoning.
-may be ‘absent’ (impaired consciousness).
-last just a few minutes.
-often no memory of episode.
-> often called ‘temporal lobe epilepsy’ cause localised in temporal lobe.
What is generalized epilepsy?
Can have two types.
->Petit Mal Seizures: can be involve entire brain (generalised). Person is briefly ‘absent, disrupted consciousness’. May not know they were absent. Common in children often disappear with age. Widely undiagnosed.
-> Grand Mal seizures: involve entire brain (generalised). Lose consciousness, fall to ground, rigid extend all limbs (tonic phase) then have jerks in all extremities ( colonic phase).
What is an aura?
Abnormal sensation e.g. sense of fear, taste of metal. Occasional symptoms preceding partial seizures. Auras due to abnormal electrical activity originating from seizure focus- earliest manifestation of partial seizure.
How can petit seizures generalise?
Some cases, quite specific + small parts of brain be source of seizure activity. Be in case in cases of localised brain damage (stroke, head injury) or following an infection, or presence of a tumour. Surgery to remove the problematic tissue could be option in such cases. Partial seizures can spread.
What happens in the brain during a seizure?
EEG detects synchronised activity of many neurons- ‘field potentials’. Diagnosis based on EEG measures, plus neuropsychological symptoms. Extensive synchronisation of firing across many neurons. Seen by EEG measures and other invasive measures, including cell-specific recording.
‘Spike and wave’ (at 3Hz) associated with petit mal generalised seizures.
How can we induce seizures in animal models?
Inject excitatory agents into cortex of anaesthetised rat. Recreate epileptic activity, a seizure that spreads. Investigating treatment possibilities including using focal cooling of the seizures focus.
What are the treatments for epilepsy?
-pharmacological: carbamazepine, phenobarbital, phenytoin (dilantin), valproic acid. = drugs targeting GABA (inhibitory actions on neurons) of NA+ channels (inhibit brain activity- cause have all these big waves and want to calm them down).
-these strategies aim to dampen down excessive neural firing, e.g. increasing release of inhibitory neurotransmitter GABA.
-surgery.
