Lecture 15, 16: Memory Flashcards
Review: Name the parts pointed in the image below.
- A: Pyriform cortex
- B: Rhinal Sulcus
- C: Entorhinal Cortex
- D: Parahippocampal cortex
- E: Hippocampal sulcus
- F: Collateral sulcus
- G: Occipito-temporal sulcus
- H: Fusiform gyrus
- A, B, C together: Parahippocampal gyrus
Before the 1950’s how was the limbic medial temporal lobe called?
Rhinencephalon
(nose brain)
Where is the perihinal cortex?
Within the lateral bank of the rhinal sulcus.
In yellow in the image below.
How can you know where the entorhinal cortex ends and where the parahippocampal cortex begins?
The Perirhinal cortex ends at the same point where the retorhinal cortex ends.
Here is an image of the MTL in a Monkey.
What is the red line highlighting? And the blue?
Red: Amygdala
Blue: Hippocampus
What does MTL stand for?
Medial Temporal Lobes
What is the area of the brain which is most commonly found to be the focus/source for epileptic patients?
MTL
What is an alternative solution for epileptic patients whose medication is not enough?
Surgically remove the focus from where the epilepsy originates
The procedure which involves removing the focus from where epilepsy originates in patients was known as?
The Montreal procedure (thanks to Dr. Penfield at the MNI)
True or False
Since most epileptic patients had as source the MTL, it was common to do a bilateral anterior temporal lobe removal. Most patients would then recover and the seizures could be controlled with medication.
False.
Most procedures were unilateral removal of the anterior temporal lobe. H.M. had a bilateral removal which caused him to be unable to recover correctly.
True or False
Before H.M. no one had performed bilateral anterior temporal surgeries.
False, Sr. Scoville had performed the surgery although rarely.
Who was the doctor who operated on H.M.?
Dr. Scoville
What was the salient symptom of H.M.’s unsuccessful recovery?
He was unable to consolidate new memories
What was H.M.’s diagnosis?
Anterograde amnesia
True or False
Limbic MTLs are important for consolidation to long term memory but NOT for storage.
True
How did H.M.’s IQ was affected by the procedure?
H.M.’s IQ increased after the procedure. It is thought that since the seizures diminished to the point of them being able to be medically controlled, now the brain had enough resources to use its full potential.
Did H.M. lose all of his memories?
No, he could remember everything pre-operation although up to 1 or 2 years before the operation is more blurred.
Which parts of H.M.’s cognition were intact after the surgery?
Language, perception, motor control, attention
Who was Brenda Milner?
- PhD student of Hebb
- Tested Penfield’s patients at the MNI
- Worked with H.M. for 50 years (until his death)
What test with Milner made H.M. do which allowed her to test his motor learning abilities? What were the results and Milner’s conclusion?
- Mirror-drawing task
- Results:
- H.M. couldn’t recall having done the task previously but was improving every day
- Conclusion:
- Memory comes in different forms
What is the Mirror-drawing task?
- Consists of using the reflection of a mirror to draw within the lines of a star
- healthy people get better each day
What is declarative memory?
Declarative memory is episodic. It has to do with events, semantics, facts and knowledge.
Relies on the Limbic MTLs for consolidation
What is procedural memory?
- Procedural memory is a more general circuit that doesn’t only involve motor memory but also habits formation.
- It has to do with the behavioural response to a stimulus
- Depends on simple stimulus-response reward feedback.
- Relies on the Basal ganglia structures (reward)
- DOES NOT rely on the limbic MTLs for consolidation
What structures are involved in procedural memory?
-
Striatum
- Putamen
- Caudate Nucleus
- Globus Pallidus
-
Basal ganglia
- Striatum
- Amygdala
- other structures important for motor learning and procedural memory
What type of connections were identified to support procedural memory?
- Cortico-striatal pathway
- Unidirectional connections from cortex to all over the caudate nucleus
During the summer, your friend invited you to go on a bicycle ride. At this, you remember that your sister taught you on an old red bicycle your grandpa owned. To your surprise, after years of learning and not being on a bicycle, you still remember how to ride it.
Which aspects of your memory are procedural and which ones are declarative?
- Declarative:
- bicycle and bicycle ride (what it is/semantic)
- red, old bicycle
- sister taught you
- Procedural:
- know how to ride the bicycle