Learning And Memory Flashcards
Define memory
Memory is the ability to store, retain and recall information we have gained through learning
What is learning?
Learning is the the process by which we acquire information from the world around us e.g. Acquisition of new skills
Broadly, what are the two types of memory?
Declarative (conscious) Non declarative (non conscious)
What are types of declarative memory?
Episodic
Semantic
What the are types of non declarative memory?
Priming
Procedural
Non associative
Associative
How do we form non associative memories?
Through habituation and sensitisation
How do we form associative memories?
Through associative conditioning (classical or operant)
In what animal model has habituation been studied in?
Aplysia by Eric Kendall
What is habituation?
The process by which a repeated stimuli will eventually become less noticeable. The response is dampened by repeated stimulation
Where does non associative memory occur?
Within the spinal cord (spinal reflex)
Why is habituation useful?
Allows for the differentiation between a harmful/ harmless stimuli
How do studies in aplysia show habituation?
They show a reduced gill withdrawal reflex secondary to repeated siphon skin stimulation. Due to reduced neurotransmitter from the sensory neuron to the motor neuron
What is sensitisation?
Where some sort of harsh stimulus actually an intensified responce. Form of learning to protect us from harm of danger. I.e. Repeated stimulus increases the response
Where does classical and operant conditioning occur?
Within the cerebellum
Describe classical conditioning
Normally and unconditioned stimulus (US) will elicit and unconditioned reaction (UR). This is physiological and unlearned. Upon pairing the US and conditioned stimulus (CS) you will still get the UR. However, if this is repeated and the US and CS are paired and the CS will be associated with the UR with each other in an optimal time frame, the CS alone will elicit an similar response. This will be know as the conditioned response .
What is the process by which the CR can be unlearned?
Extinction.
This may occur if the CS is no longer predicative of the US. I.e. The bell after a while is no longer paired with the food the CR will no longer be elicited by the CS
What is operant/instrumental conditioning?
where behaviours are learnt to be repeated or attenuated based on the consequence of the behaviour. Essentially a relationship between a behaviour and a consequence is learned.
How may a behaviour be reinforced to occur?
If the consequence of the behaviour is positive (positive reinforcement) or a noxious stimuli is removed following behaviour or behaviour avoids the noxious stimuli i.e. Escape (negative reinforcement)
How through operant condition and a behaviour be attenuated?
Through punishment
I.e. Behaviour = addition of noxious stimuli (positive punishment)
OR
Behaviour = removal of a positive of a positive stimulus e.g. Removing a child’s toy when the misbehave
What drives operant conidtioning?
Motivation i.e. Animal will not press the lever to recover food of it is not hungry.
How is classical and operant conditioning different?
May occur through similar neuronal pathways.However, classical conditioning occurs when a CS is predicative of a US. In operant a particular behaviour is associated with a particular consequence
Where does fear conditioning occur?
Within the amygdala
where is procedure memory learnt?
In the striatum and cerebellum
What is procedural memory?
Learning a habit or motor response/ sequence in reaction to sensory stimuli. I.e how to ride a bike
What do striatum lesions affect?
Non declarative memories
What experiment can be done to test declarative memory?
Lesion the hippocampus whilst doing the delay non-match to sample experiment in monkeys
What is the delayed non-match to sample experiment?
Monkey faces a table with several wells. Initially one object (wooden block) covers one of the wells and monkey is trained to lift a object to get to food in the well). A screen then prevents the monkey seeing the table for some period of time (delay interval). Table then reveal but now two objects cover two different wells, one is the same as before and the other is new). In a match to sample test the animal must delay the object it recognises to get the food. In a delayed non-match to sample the animal must displace the new object to get the food reward.
What does DNMS teach us about the hippocampus in memory?
Bilateral hippocampal lesions in monkeys
Performance was normal if delay period was a few seconds between the two experiments. (Indicates that the animals perception was still intact and the animal remembered the DNMS procedure). However, after a few minutes the animals would have more errors in choosing the non matching stimulus. I.e. Animal was no longer good at membering the object they were taught to recognise (sample stimulus) is delay was too long.
What structures are essential for declarative memory?
Hippocampus
The entorhinal cortex (peri rhinal especially)
How do animals with a striatal lesion perform in the DNSM task?
They perform fine means declarative memory is intact
What do animals with lesions of the striatum have impairments in?
Forming habits i.e. In the DNSM apparatus monkeys will be exposed to two to visual stimuli and have to lift one shape to receive the reward underneath. This form of instrumental conditioning is impaired. I.e. Animal shows impairment of retrieving the food associated with one visual stimulus rather than another. Therefore, learned habits use the striatum.
What do patients with huntingtons disease show?
Impairment of learning a task where a motor response is associated with a stimulus.
What is priming?
Unconscious enhanced recall of primed objects
What is declarative memory?
Conscious recall of information about people, places of things
What is needed for decorative memory?
Temporal lobe (possible site of consolidation/ storage of memory engrams) Diencephalic structures e.g. Hippocampus subiculum and entorhinal cortex. (Site of memory formation)
Where does priming occur?
The entire cortex
What is episodic memory?
Refers to memory of specific events in time. Unique event which only happened once so no chance for rehearsal (involves the cortex)
What is semantic memory?
Refers to knowledge of the external world e.g. What is the capital of France involves frontal and temporal lobe
What did patient H.M have removed?
Bilateral hippocampal removal
2/3 of hippocampus formation, parahippocampal gyrus (removal of all entorhinal cortex) and amygdala
What did patient HM show?
Severe anterograde amnesia (short term memory was intact but could not form new memories)
Moderate retrograde amnesia (perhaps showing these structures to be important in memory storage too i..e could not remember some events 11 years before surgery)
What was left intact for patient HM?
The ability to have procedural memories and motor skills. He was able to draw a figure looking at his reflection in the mirror
