Temporal Lobe Flashcards
What is required to store memories?
Synaptic plasticity
Define long term potentiation?
Increase in the efficiency of a specific synapse which results from activity at the specific synapse
State the exact synaptic location memory occurs, and describe the impulse route?
Input from the entorinhal cortex goes to the hippocampus (dentate gyrus) and from here mossey fibres carry impulses to CA3 cells and from here to CA1 cells.
The synapse between CA3 and CA1 is where memory occurs
Name the three things required for long term potentiation to occur?
Glutamate (neurotransmitter)
Ca 2+
NMDA receptors (has Mg 2+ in channel pore)
How are NMDA receptors unblocked?
Glutamate neurotransmitter enters the cell via metabotrophic AMPA receptors and depolarises the cell. This depolarisation leads to the Mg2+ ion ‘popping out’ of the NMDA pore and allowing Ca 2+ to influx
What occurs immediately after co-incidence activation of NMDA receptors?
Ca 2+ causes a chain reaction leading to more AMPA receptors being placed on the synaptic membrane and therefore depolarisation next time will occur more easily
What can inhibit memory formation and LTP?
Blocking protein synthesis
In terms of neurotransmitters describe the affect of Alzheimer’s disease?
Over-activation of glutamate
Under-activation of Ach
Describe temporal love epilepsy?
Some temporal lobe neurones have a low threshold for ‘deranged synchronisation’ this can lead to seizures
In the limbic system where does ‘emotional colouring’ occur?
Neocortex
In the limbic system where is ‘emotional experience’ located?
Cingulate cortex
Describe primary progressive aphasia?
Fronto-temporal atrophy, with speech as a-grammatical and non-fluent
Describe expressive/Broca’s aphasia and where do lesions occur?
Typically caused by stroke (MCA) characterised by non-fluent and a-grammatical speech
Left frontal lobe
Describe Wernicke’s/receptive aphasia and where do lesions occur?
Can speak the language but can’t understand
Posterior temporal lobe damage
Describe conductive aphasia and where does damage occur?
Damage to the superior longitudinal fasiculas (arcuate fasiculus) that connects Broca’s and Wernicke’s areas. Fluent speech with lots of filler words but can’t repeat words on command
Where is word visualisation comprehended?
Angular gyrus
