Structure and Function of the Hippocampus Flashcards
What structure is adjacent to the hippocampus?
Entorhinal Cortex
What parts of the hippocampus receives many of the inputs from the neocortex?
Dentate Gyrus
Which one is a glutame receptor?
NMDA
Which cortical region strongly connected to the hippocampal is associated with spatial processing?
Parahippocampal Cortex
An influx of which positively-charged ion gives rise to LTP?
Calcium
Which positively-charged ion must be moved out of membrane pores for LTP to occur?
Magnesium
Where does most LTP take place in the hippocampus?
Between CA3 and CA1 cells
What do NMDA knock-out mice do in the water maze?
Find the platform by trial and error each time
What task was used to investigate relational memory in rats?
Transitive Inference Task (Beakers)
What is the difference between recollection and familiarity?
Only recollection involves mental time travel
how did the hippocampus get its name?
hippocampus means seahorse of the similar structure / shape -> structure is very important for the functions (as functions change along the hippocampus
what does long-term memory at the level of individuals neurones reflect?
structural changes at the synapse
- when we learn something we aren’t just changing the chemical makeup of the brain but we are physically changing the synapse itself allowing us to learn new long-term memories
Which anaesthetic used as a recreation drug disrupts the ability to form memories?
Ketamine is an NMDA receptor (type of glutamate receptor) supporting memory function
- Ketamine causes memory disruption
Where is the hippocampus?
medial temporal lobes / cortex (buried deep inside)
what is the hippocampus structure?
- along its lengths, the hippocampus shows distinct cell fields that are tightly folded
- the connections between these cell types are relatively well-understood
what is structure like within the hippocampus?
- Inputs via dentate gyrus
- Associations between CA1 and CA3 fields
- Outputs via subiculum
describe the layering of the hippocampus
layers are wrapped around each other and usually connected up -> helping us understand how long-term memories are supported by the hippocampus
There are four main types of cell fields within the hippocampus, what are they?
- CA3 and CA1 Neurones
- Subiculum
- Dentate Gyrus
How is information received and outputted in the hippocampus?
- Hippocampus receives input primarily via the dentate gyrus
- Dentate gyrus projects to CA3 and CA1 subfields of the hippocampus
- They send their outputs to the subiculum (output via subiculum) (major output system of the hippocampus)
What components sit next to the hippocampus? [need to find out how the hippocampus is connected to the adjacent cerebral cortex]
In order of closest to furthest:
* Entorhinal Cortex
* Perirhinal Cortex
* Parahippocampal Cortex
what is the hippocampus structured from and how is this different from the entorhinal cortex?
hippocampus has an unusual structure and is allocortex (different micro-structure from the cerebral cortex)
While Entorhinal cortex is a neocortex
what is the role of the Entorhinal cortex?
acts as a gateway between information in the rest of the cerebral cortex and hippocampus
what is the Perirhinal cortex important for?
localised site important for object recognition (/representation)
* stronger response in this cortex when using object recognition
what is the parahippocampal cortex important for?
spatial layout coding
- more activation when representing location (location representation)