Higher Cortical Function: Memory Flashcards
Define learning.
Define memory.
- Learning is the acquisition of knowledge.
- Memory is the retention of knowledge.
What is declarative memory?
Give an example of a characteristic of declarative memory.
List and describe the types of declarative memory.
- Declarative memory is memory of factual information - the ‘what’.
- Declarative memory fades with time.
Types of declarative memory include:
1 - Semantic memory: memory of facts.
2 - Episodic memory: memory of events.
What is non-declarative memory?
Give an example of a characteristic of non-declarative memory.
List and describe the types of non-declarative memory.
- Non-declarative memory is memory of skills, habits and behaviours - the ‘how’.
- Non-declarative memory is less likely fade with time.
1 - Procedural memory: memory of skills and habits.
2 - Conditioned responses, e.g. associative reflexes (such as Pavlov’s dogs).
3 - Emotional responses.
What is the average capacity for short-term memory?
7 items is the average capacity for short-term memory.
Define consolidation.
The process of converting short-term memory into long-term memory.
What is working memory?
Working memory is the process where information is taken in and processed or factored in with other existing memory.
What changes occur in the brain to cause memory loss?
Loss of synapses (not neurones).
Define amnesia.
List 5 causes of amnesia.
Amnesia is memory loss secondary to other pathologies:
1 - Traumatic brain injury.
2 - Infection.
3 - Neurodegeneration, such as Alzheimer’s.
4 - Resection.
5 - Stroke.
List and describe the types of amnesia.
1 - Retrograde amnesia: partial loss of (particularly declarative) memories that were established before the onset of amnesia.
2 - Anterograde amnesia: inability to form new memories following the onset of amnesia.
What is Ribot’s law?
The idea that recent memories are more likely to be lost than older memories.
Which area of the brain is responsible for declarative memory?
Where is this information held in the short-term and long-term?
- The hippocampuses of the medial temporal lobes are responsible for declarative memory.
- The temporal lobes are particularly important in the formation of new memories rather than retention of old memories. Other cortical areas are important for long-term memory.
What changes occur in the brain during consolidation of memory?
- Memory moves from the hippocampuses of the medial temporal lobes to the neocortex.
- It travels through the hypothalamus, and then the thalamus before reaching the neocortex.
Which structures of the thalamus are responsible for the conveying of memories from the hippocampuses of the medial temporal lobes to the neocortex?
Mammillary bodies.
What is Korsakoff’s syndrome?
Give an example of a symptom of Korsakoff’s syndrome.
- Korsakoff’s syndrome is a syndrome characterised by episodic memory loss, most usually associated with alcohol abuse.
- It is caused by degeneration of mammillary bodies in the thalamus, meaning information can’t reach the neocortex for long-term memory formation.
List the areas of the brain that are responsible for non-declarative memory.
Procedural:
1 - Cerebellum.
2 - Supplementary motor area.
3 - Basal ganglia.
Emotional:
4 - Amygdala.
Why does Parkinson’s disease cause memory loss?
How is memory affected in Parkinson’s disease?
- Parkinson’s disease causes memory loss because it is caused by degeneration of the substantia nigra (one of the basal ganglia).
- In particular, patients suffering from Parkinson’s disease have a reduced ability to form new memories.
Which area of the brain is responsible for working memory?
The prefrontal cortex is responsible for working memory.
Why might patients suffering from ADHD and schizophrenia have a poor working memory?
Patients with ADHD and schizophrenia might have a poor working memory because they have damage to the frontal lobe, which is responsible for working memory.
Define neuroplasticity.
Neuroplasticity includes changes in:
1 - Neurotransmission (long term potentiation).
2 - Synaptic structure.
What is long-term potentiation?
- Long-term potentiation is a mechanism for change in neurotransmission that contributes to neuroplasticity:
- Repeated interactions between a presynaptic and postsynaptic neurone increases the sensitivity of the postsynaptic neurone to the activity of the presynaptic neurone.
Describe the mechanism for long-term potentiation.
- In a synapse using glutamate at AMPA and NMDA receptors, glutamate binds to both AMPA and NMDA receptors to cause an excitatory postsynaptic potential.
- Activation of NMDA also causes Ca2+ influx, which enhances the activity of a kinase known as CAMKII.
- In the short term, enhanced CAMKII activity enhances AMPA activity.
- In the long term, CAMKII increases gene expression of AMPA receptors. This results in more AMPA activity, and therefore a greater excitatory postsynaptic potential.
How does synaptic structure change contribute to neuroplasticity?
- Repeated interactions between a presynaptic and postsynaptic neurone causes the presynaptic neurone to form axon sprouts.
- Growth cones at the tips of the axon sprouts guide the axon sprouts to the postsynaptic neurone.
- The axon sprouts then form more synapses at the postsynaptic neurone.
- This increases the sensitivity of the postsynaptic neurone to the activity of the presynaptic neurone.
How does age affect memory?
- Age results in a decrease in neuroplasticity.
- However, age does not result in the loss of synaptic connections that are responsible for memories that are already established.
- This means that age decreases a person’s ability to form new memories, but doesn’t necessary result in the loss of memories that are already established.
What are nootropics?
Nootropics are drugs that improve cognitive function, including memory.
Give an example of a pharmacological suppressor of memory.
Why might this be useful?
- NMDA antagonists such as ketamine are used as suppressors of memory.
- It can be used clinically for patients with post-traumatic stress disorder, where memories of traumatic events are enhanced.
What is sensory memory?
Describe the flow of information in the brain starting from sensory memory.
- Sensory memory is the temporary storage of information in the brain in the few fractions of a second after a stimulus is perceived.
- Information in the sensory memory is held in the brain whilst it is being moved to the short-term memory.
- With consolidation, this information can become long-term memory.
