synaptic excitation and inhibition: epilepsy Flashcards
what is the major excitatory NT in the brain?
-glutamate
what is the major inhibitory NT in the brain?
GABA
what antagonists trigger seizures?
GABA antagonists
what antagonists stop seizures?
glutamate antagonists
what channel mutation can cause brain hyperexcitability?
mutation of genes encoding voltage / ligand gated ion channels
to which part of the brain does damage result in hyper excitable networks
the hippocampus
what is a seizure?
transient occurrence of signs and symptoms due to abnormal excessive or hyper synchronous neuronal activity in the brain
how are seizures classified?
-into focal and generalised onset
what is focal onset seizures?
-these seizures originate in 1 area of the brain
- 2 types - social aware and focal impaired awareness seizures
what is a focal aware seizure?
person is conscious during seizure and can recall the event afterwards
what is a focal impaired aware seizure?
the person looses consciousness or awareness during the seizure & may have unusual behaviours
what are generalised onset seizures?
seizures that involve both hemispheres of the brain
what are the different types of generalised onset seizures?
-non motor (absence)
-motor - tonic, clonic, atonic etc
what is a motor generalised onset seizure?
a seizure involving changes in muscle activity such as loss of postural tone eg muscle stiffening, jerking etc
what is the difference between tonic vs clonic Motor generalised onset seizures?
-tonic - sustained contraction - arching back
-clonic / clonus - rhythmic contraction
what are examples of clinical features of a seizure?
NB can vary a lot depending on location and extent of neurons
-disordered thought
-temporary confusion
-loss of consciousness
-urinary incontinence
-eyes rolling etc
what is status epilepticus?
-A seizure that lasts longer than 5 minutes, or having more than 1 seizure within a 5 minutes period, without returning to a normal level of consciousness between episodes
what effect do epileptic seizures have ion the brain?
-can injure the brain
-altered gene expression
-inflammation
-cell death and gloss
what is an EEG?
an electroencephalogram
-records activity generated by the brain
what can brain imaging eg MRI help to diagnose?
-structural abnormalities
-functional abnormalities
what is epilepsy?
a brain disorder in which a person has recurring seizures
- at least 2 unprovoked seizures occurring more than 24 hrs apart
what is epilepsy syndrome?
An epilepsy syndrome is a type of epilepsy that is identified by a specific seizure type or types and by the findings on an EEG
what are unknown onset seizures?
-seizures where the precise origin or onset within the brain cannot be determined with certainty.
- In these cases, there may not be enough clinical information, EEG data, or imaging studies to confidently classify the seizure as focal or generalized.
