Memory Flashcards
What is memory?
- The capacity to encode, store and retrieve information
- A lasting trace of past experiences that influence current or future behaviours
What does it mean to say that the different forms of memory appear to be separable?
One can be damaged leaving another in tact
What are the two divisions of long term memory?
Explicit (Declarative)
Implicit (Non Declarative) aka procedural memory
What does “implicit” (non-declarative memory refer to?
The memory/performance of things that takes place without our awareness e.g. skills that were learned with awareness but are now performed without thinking (procedural)
What is the Serial Reaction Time Task (SRT task)?
A common way to test procedural memory
- A shape appears in one of 4 locations on a screen, Ps have to press corresponding button ASAP
- This repeats with the shape appearing in different positions in random order
- The first block of the task is in Pseudo-random order for 24 trials, AKA Baseline (B)
- The second block of the task is an Implicit Learning Block (IL), shape follows a sequence for 12 trials
- Baseline and Implicit Learning Blocks alternate
What happens to Reaction Times in the Serial Reaction Time (SRT) Task?
Implicit Learning block RTs decrease over time to a greater extent than for Baseline blocks
- because when the IL sequence appears again, Ps motor responses are faster than the first time they saw it because its familiar (even though they don’t know)
- RT for B is likely to decrease over time due to practice
- RT for IL will decrease significantly due to implicit sequence learning
What did Rauch et al., 1997 find in their fMRI study with the Serial Reaction (SRT) task?
Found increased activation in the right striatum during sequence learning compared with baseline blocks
Found that in Ps who showed greatest amount of implicit learning, the magnitude of activation in the right putamen was correlated with the decrease in RT
Which form of long term memory is the Medial Temporal Lobe (MTL) crucial for?
Declarative memory
- episodic
- autobiographical
- semantic
What happens to memories in the hippocampus?
Consolidation
they change from being short-term to long-term
What factors effect Consolidation?
- depth of stimulus processing
- distinctiveness
- relevance
- emotionality
How do stressful or emotionally exciting experiences effect memory consolidation & storage?
Adrenaline and cortisol secretion increase
- small to moderate amounts of cortisol activate the amygdala & hippocampus, which increases memory consolidation and storage
What is the benefit of greater processing of negative or threat related information?
Allows for better avoidance of dangerous situations
- clear evolutionary advantage
What is re-consolidation?
When a memory is reactivated (retrieved/remembered), it is brought into a labile state
- in this labile state it is fragile/malleable
- so the memory can be weakened or altered
- OR the memory can be strengthened
What brain mechanisms are used to consolidate a long-term memory?
- Specific axon repetitively stimulation another axon leads to growth/metabolic change that would connect them more strongly (Hebb)
- Changes happening at the synapse between neurons of the hippocampus cause memories to be created
What is Long Term Potentiation (LTP)?
- The way memories are consolidated
- Changes that happen at the synapse between neurons of the hippocampus, when one or more axons bombard a dendrite with stimulation
- Mainly depends on activity at Glutamate synapse
What is Long Term Potentiation called Long Term Potentiation?
Because the repeated stimulation leaves the synapse “potentiated” for a period of time, mean it is more responsive
What types of Glutamate receptor are important for Long Term Potentiation (LTP)?
AMPA
NMDA
Why are the AMPA and NMDA Glutamate receptors known as ‘inotropic receptors’?
Because when they are stimulated they open channels for ions to pass through
What is meant by ‘AMPA is a typical inotropic receptor’?
It opens sodium channels (Na+) when stimulated by Glutamate