Learning and memory Flashcards
Importance
- Sense of self
- Survival: detecting threats
- Learn predictive value of signals
- Understand when it goes wrong
- Understand how behaviour is shaped by experience
Learning and memory
-The acquisition and retention of change in behaviour
Behaviour
-Acquired and maintained by synaptic plasticity, conditioning, perceptual and relational learning.
Synaptic plasticity
- Ability to learn and regenerate lost skills
- Synapses strengthen or weaken over time due to increase or decrease in activity
Hebbs rule
-If a synapse is repeatedly activated the structure or chemistry will change and become strengthened
Hebb rule evidence
- Bursts of 100 electrical pulses were sent through a pathway to the hippocampus. then a single pulse was delivered later which showed an increased response in the structure at the end of the pathway
- Blink neuron was activated by a puff of air to the eye paired with a music note. This strengthened the connection between the neurons so the music note on its own would cause blinking
Location of plasticity
-Hippocampal formation is the major area for learning and memories
Long term potentiation
- Strong activity releases glutamate which activates NMDA receptors which release calcium which strengthens connections
- seizures, anorexia or hypoglycemia cause abnormally high levels of glutamate which causes an influx of calcium which can be toxic and destroy neurons
Long term depression
-AMPA receptors are removed which reduces the connections and efficiency of the synapse
Perceptual learning
-Subconscious ability to learn to recognize new stimuli or changes/variations of new stimuli
Learning to recognise stimuli
-Synaptic connections in the visual association cortex change to create new neural circuits for recognition e.g. when the visual association cortex was stimulated, memories/images were recalled
Learning to respond to stimuli after a short delay
-If you see someone walk into a room, and you look away you know they are still there due to continued activity in the neural circuits in the fusiform face area of the visual association cortex (perceptual short term memory)
Classical conditioning leads to learning
-Conditioning can create emotional responses e.g. little albert.
Neural processes of classical conditioning
- A loud noise activates synapses in the lateral nucleus, which activates the central nucleus creating a fear response
- If this is paired with an unconditioned stimulus the connection is strengthened causing the synapses to fire together as the AMPA receptors between the synapses in the lateral amygdala and the axons that cause the conditioned fear are strengthened which creates a conditioned response
Instrumental conditioning (operant conditioning)
- Allows us to profit from experience e.g. if we make a response that has a favorable outcome, then it is likely going to be repeated.
- The actions associated with instrumental conditioning begin in the sensory association cortex and end in the motor association cortex of the frontal lobe.
Transcortical pathways between sensory and motor association cortex
- Involved in the acquisition of complex behaviors relevant to deliberation and instruction (memorized set of rules/script) e.g. learning to drive
- All consuming process, requiring explicit concentration and effort
Basal ganglia and thalamic pathways
-Over time actions become rehearsed (habitual), at which time the basal ganglia and thalamus table over the process subconsciously allowing us to use the transcortical pathway to learn new things.
Action of reinforcement
- There are several reinforcement mechanisms in the brain including the dopamine system e.g. mesolimbic and mesocortical dopaminergic systems
- The medial forebrain bundle connects the ventral tegmental area if either is stimulated (by reward or drugs) dopamine is released from the nucleus accumbens
Factors that impact reinforcement
- Motivating operation: stimuli may work as a reinforcer on one occasion but not another (hungry bs sated).
- Unexpected vs expected: Berns et al (2001) found that an unexpected squirt of juice activated the nucleus accumbens, but that predictable delivery did not. VAT dopaminergic neurons signal to other areas of the brain that something must be learnt. If the reward was predicted nothing needed to be learnt.
Most memories are connected
- Most episodic memories of real objects and events are related to other memories
- When you see a friend, you remember how to say their name, and the memories shared with them which lead to the reactivation of a specific series of events
Relational learning
- The neural circuits in the visual association are connected to circuits in many other parts of the brain, and these are connected to many others.
- Includes the establishment and retrieval of memories of events, episodes and places
Anterograde amnesia
-In its simplest form is the inability to learn new information
Anterograde amnesia pure
-Able to remember past events from before the brain damage but cannot remember any information learnt after. Very rare, often occurs with retrograde amnesia.
Pure retrograde amnesia pure
-Inability to remember events that happened before the brain damage occurred
