DP1 Role of Hippocampus and Amygdala
Terms in this set (9)
Role of the Hippocampus
-The hippocampus is crucial for long-term memory formation (not all types), specifically:
- forming or encoding new declarative explicit memories (semantic and episodic)
-not directly involved in forming or retrieving implicit procedural memories
-This role is called consolidation, where newly forming memories are strengthened to enable permanent storage
Damage of the Hippocampus in Memory:
-Does not seriously affect storage or retrieval of procedural memories
-Does not affect short-term storage or working memory in any way
-Does affect remembering the location of objects
-Does seriously affect formation and retrieval of declarative memory → difficulties forming new explicit declarative memories
After Removal of Temporal Medial Lobe:
Experienced Anterograde amnesia:
memory loss for experiences after trauma or surgery
Role of medial temporal lobe in formation of new LTM (especially declarative memory) -->responsible for encoding STM to LTM
Could hold normal conversation, complete puzzle, rehearse numbers as long as he was not distracted. However, could not form LTM such as his doctor's names and needed to be reintroduced every time.
Damage did not affect STM but LTM- therefore they must be different systems. Hippocampus is not involved in STM storage.
Interestingly, able to learn new motor skills (eg. 'mirror drawing')
Hippocampal area of temporal lobe has an important role in forming new declarative memories but not implicit ones.
Although he could not form new memories, he did not lose access to any memories that had been stored before his surgery
Once formed in the hippocampal area the memory is then sent to the cortical areas of the brain specialised for storage of memory. LTM has independent storage and retrieval processes.
Conclusions for H.M Case Study:
-The STM (or working memory) and LTM are different systems
-The hippocampus does not affect STM storage
-The hippocampus is not a vital structure in forming or storing procedural memories
-The hippocampus does not store declarative LTMS, but is vital in forming them and transferring them to other cortical areas for storage.
Role of Amygdala: processing and regulating emotional reactions
-It is involved in the encoding and storage of memories that have a significant emotional component
→ People who damage their amygdala have difficulty learning emotional responses and interpreting expressed emotions.
We tend to be more likely to remember events that produce strong emotional reactions, than events that do not.
→ One reason: amygdala attaches emotional significance to information and stimulates the hippocampus to encode the explicit info regarding the event
→ Another reason: Norepinephrine 'tags memory of an event with important emotional details and strengthens its long term storage
(Increased levels of norepinephrine at amygdala during arousal communicates to hippocampus that details of the exxperience are significant- strengthen stroge by hippocampus)
Fear Response (Role of Amygdala and Hippocampus)
Encodes Unconscious, non-verbal, emotional procedural information (implicit info)|
-> Can also contribute to explicit memory storage by influencing activity of the hippocampus
-Interacts with Cortical Areas and stores/encodes Conscious, Verbal, Cognitive and declarative information (explicit information)