Podcast
Questions and Answers
What occurs during memory reconsolidation?
What occurs during memory reconsolidation?
What does cue-dependent amnesia suggest about memory?
What does cue-dependent amnesia suggest about memory?
What is an effect of injecting protein synthesis inhibitors into the hippocampus?
What is an effect of injecting protein synthesis inhibitors into the hippocampus?
What happens to a memory while it is in the 'active' state, according to active trace theory?
What happens to a memory while it is in the 'active' state, according to active trace theory?
Signup and view all the answers
Where does memory recall transition from during the consolidation process?
Where does memory recall transition from during the consolidation process?
Signup and view all the answers
What characterizes the response of the hippocampus during remote memory tests?
What characterizes the response of the hippocampus during remote memory tests?
Signup and view all the answers
Which type of CaMKII is crucial for synaptic consolidation in the cortex?
Which type of CaMKII is crucial for synaptic consolidation in the cortex?
Signup and view all the answers
What happens to learned memories in patients with medial temporal lobe damage according to Multiple Trace Theory?
What happens to learned memories in patients with medial temporal lobe damage according to Multiple Trace Theory?
Signup and view all the answers
What role does the prefrontal cortex (PFC) potentially play in the standard model of memory consolidation?
What role does the prefrontal cortex (PFC) potentially play in the standard model of memory consolidation?
Signup and view all the answers
What type of amnesia refers to the inability to form new memories following trauma?
What type of amnesia refers to the inability to form new memories following trauma?
Signup and view all the answers
What happens to AMPAR when glutamate activates it during long-term potentiation (LTP)?
What happens to AMPAR when glutamate activates it during long-term potentiation (LTP)?
Signup and view all the answers
How does protein synthesis affect memory consolidation according to the reviewed content?
How does protein synthesis affect memory consolidation according to the reviewed content?
Signup and view all the answers
What does retrograde amnesia typically result in?
What does retrograde amnesia typically result in?
Signup and view all the answers
What model suggests that the hippocampus initially stores memories and later transfers them to the cortex?
What model suggests that the hippocampus initially stores memories and later transfers them to the cortex?
Signup and view all the answers
In the context of memory research, what effect does lesioning the MTL have on memory retrieval over time?
In the context of memory research, what effect does lesioning the MTL have on memory retrieval over time?
Signup and view all the answers
What physiological change occurs when NMDA receptors lose their Mg2+ block during LTP?
What physiological change occurs when NMDA receptors lose their Mg2+ block during LTP?
Signup and view all the answers
What is a significant role of the hippocampus in memory processes?
What is a significant role of the hippocampus in memory processes?
Signup and view all the answers
Which type of memory is lost due to damage to the medial temporal lobe (MTL)?
Which type of memory is lost due to damage to the medial temporal lobe (MTL)?
Signup and view all the answers
The hippocampus is solely responsible for long-term memory storage.
The hippocampus is solely responsible for long-term memory storage.
Signup and view all the answers
What process is disrupted in patients who experience retrograde amnesia?
What process is disrupted in patients who experience retrograde amnesia?
Signup and view all the answers
The activation of NMDA receptors during long-term potentiation (LTP) allows for the influx of __________ ions.
The activation of NMDA receptors during long-term potentiation (LTP) allows for the influx of __________ ions.
Signup and view all the answers
Match the type of memory loss with its description:
Match the type of memory loss with its description:
Signup and view all the answers
What role does protein synthesis serve in memory consolidation?
What role does protein synthesis serve in memory consolidation?
Signup and view all the answers
Hippocampal activity becomes less important for memory retrieval as the memory ages.
Hippocampal activity becomes less important for memory retrieval as the memory ages.
Signup and view all the answers
Which model suggests that hippocampal activity is necessary for the initial phase of memory storage?
Which model suggests that hippocampal activity is necessary for the initial phase of memory storage?
Signup and view all the answers
What process strengthens synaptic connections between neurons during memory recall?
What process strengthens synaptic connections between neurons during memory recall?
Signup and view all the answers
Memory reconsolidation occurs only when a memory is recalled and is not affected by cued recall.
Memory reconsolidation occurs only when a memory is recalled and is not affected by cued recall.
Signup and view all the answers
What is the role of CaMKII in long-term potentiation (LTP)?
What is the role of CaMKII in long-term potentiation (LTP)?
Signup and view all the answers
Memory reconsolidation can be disrupted by __________ if it occurs during the active state of recall.
Memory reconsolidation can be disrupted by __________ if it occurs during the active state of recall.
Signup and view all the answers
Which statement about offline replay is true?
Which statement about offline replay is true?
Signup and view all the answers
Match the following terms with their descriptions:
Match the following terms with their descriptions:
Signup and view all the answers
According to Multiple Trace Theory, episodic memories can be fully recalled without the medial temporal lobe.
According to Multiple Trace Theory, episodic memories can be fully recalled without the medial temporal lobe.
Signup and view all the answers
What is indicated by the results of protein synthesis inhibitors injected before and after training?
What is indicated by the results of protein synthesis inhibitors injected before and after training?
Signup and view all the answers
The hippocampus is one of the few brain areas where __________ occurs.
The hippocampus is one of the few brain areas where __________ occurs.
Signup and view all the answers
What phenomenon occurs during memory retrieval that enhances later memory consolidation?
What phenomenon occurs during memory retrieval that enhances later memory consolidation?
Signup and view all the answers
What is the first step in the process of long-term potentiation (LTP) following glutamate activation?
What is the first step in the process of long-term potentiation (LTP) following glutamate activation?
Signup and view all the answers
Injecting protein synthesis inhibitors 1 hour after training does not disrupt long-term memory until day 7.
Injecting protein synthesis inhibitors 1 hour after training does not disrupt long-term memory until day 7.
Signup and view all the answers
What role does alpha-CaMKII play in synaptic consolidation in the cortex?
What role does alpha-CaMKII play in synaptic consolidation in the cortex?
Signup and view all the answers
Memory recall transitions from the __________ to the cortex during the consolidation process.
Memory recall transitions from the __________ to the cortex during the consolidation process.
Signup and view all the answers
Match the types of memory tests with their involved brain regions:
Match the types of memory tests with their involved brain regions:
Signup and view all the answers
Study Notes
Human Memory (H.M.)
- Perceptual and motor skills remain intact
- Ability to form new memories is disrupted
- Loss of declarative memory (episodic and semantic)
- Memory intact for up to 11 years before the accident
- Then, memory gradually fades back to the accident, demonstrating temporally graded retrograde amnesia
Long-Term Potentiation (LTP)
- Glutamate activates AMPA receptors, allowing sodium influx and depolarization
- Depolarization removes magnesium block from NMDA receptors, allowing calcium influx
- Calcium activates calmodulin, leading to CaMKII activation
- CaMKII triggers actin breakdown and spine enlargement, promoting AMPA receptor recruitment
- PKA and CREB are activated, leading to mRNA production and protein synthesis, essential for synaptic plasticity
- Protein synthesis inhibitors block memory consolidation in the hippocampus
- These inhibitors prevent long-term LTP.
- Glutamate activation of AMPA receptors leads to sodium inflow, cell depolarization, and NMDA receptor unblocking, allowing calcium inflow, and activating calmodulin. This leads to CaMKII activation, actin breakdown, spine enlargement, AMPA recruitment, PKA, CREB, and finally mRNA production for protein synthesis, fostering synaptic plasticity.
Amnesia Due to Medial Temporal Lobe (MTL) Damage
- Amnesia encompasses impaired memory and learning
- Retrograde amnesia involves loss of memories before the trauma but preserved long-term memories
- Storage failure: Permanent loss of memories due to disruption
- Retrieval failure: Temporary difficulty in recalling memories, potentially due to damage in pathways
- Anterograde amnesia denotes the inability to create new memories
- Retrograde amnesia can range from recent to distant memories, depending on the time since the brain injury.
- Anterograde amnesia specifically involves an inability to store new declarative memories.
- Older memories may be stored elsewhere if not in the MTL.
- Storage/retrieval failures in the MTL can affect the ability to retain or recall memories from different periods.
Where are Older Memories Stored?
- Hippocampal involvement is crucial for retrieving memories
- Contextual fear conditioning studies in animals help to infer the memory retrieval mechanisms
- Hippocampal lesions can impair the retrieval of contextual memories.
- Damage to the hippocampus can affect memory retrieval, even for memories acquired long before the injury, depending on the timing of the lesion.
- Retrograde amnesia can be fully intact depending on the timing of the lesion (e.g., Kim & Fanselow for 28 days, Maren for 100 days, Anagnostaras for 50 days).
- Different studies have shown varying results regarding the extent of retrograde amnesia depending on the time elapsed between the injury and memory testing.
Standard Consolidation Model
- David Marr proposed that the hippocampus rapidly acquires memories and subsequently transfers them to the cortex
- Forward replay: Neurons activate in the same sequence as the original experience
- Reverse replay: Neurons activate in the reverse order of the original experience
- Hippocampal activity is initially vital, with strong connections, subsequently becoming weaker, as memories transition to the cortex (where stronger connections ultimately form).
Memory Reconsolidation
- Memory reactivation during consolidation strengthens synaptic connections
- This process is crucial for the maintenance, strengthening, and updating of long-term memories
- Cue-dependent amnesia shows the vulnerability of reactivated memories to disruption through either external electrical stimulation (ECS) or other conditioning procedures.
- Memory reactivation makes memories accessible and sensitive to disruption and alteration. Memory reconsolidation encompasses processes where a long-term memory (LTM) is recalled and re-consolidated, affecting its persistence. Memories can be reactivated due to replay or cued recall.
Active Trace Theory
- An active memory is susceptible to disruption but also allows for stronger consolidation
- Recall of a memory strengthens the memory trace and transitions from hippocampus to cortex
- Consolidation transfers it to the cortex, making it less vulnerable
- The memory is most vulnerable during transfer to the cortex.
Protein Synthesis Inhibitors in Hippocampus
- Protein synthesis inhibitors in the hippocampus impair stable long-term memories.
- Disruptions are observed hours later and are long-lasting, suggesting a crucial role of protein synthesis in memory consolidation. Protein synthesis inhibitors can disrupt long-term memories by affecting consolidation, potentially early or short term.
Multiple Trace Theory
- Suggests that episodic memories are initially stored, and subsequently transferred to the cortex. However, unlike the standard consolidation model, this theory emphasizes that not all memories are entirely moved from the hippocampus. All memories, including their original traces, are retained.
Prefrontal Cortex Involvement
- Prefrontal cortex may exert inhibitory control over the hippocampus, impacting memory consolidation.
- Prefrontal cortex may play a role in modulating hippocampal activity during memory consolidation, influencing memory traces.
Neurogenesis
- Hippocampal neurogenesis (new neuron creation) plays a critical role in memory formation, potentially impacting both memory consolidation and retrieval.
- New neurons can be created in the hippocampus dentate gyrus. Old or unused neurons are shed.
- CaMKII has different effects in different brain regions (hippocampus vs. cortex), potentially impacting learning rates. Brain regions can be differentially affected depending on factors such as the types of experiences and their intensities.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on key concepts of human memory, including the role of long-term potentiation (LTP) and the impacts of medial temporal lobe damage on memory formation. Explore how mechanisms like AMPA and NMDA receptors relate to memory and synaptic plasticity. This quiz covers crucial aspects of memory function and impairment.