Learning And Memory Flashcards
What is the definition of learning?
→ Acquisition of new information
What is the definition of memory?
→ Retention of learned information
What is declarative memory and what part of the brain is responsible for it?
→ Facts and events
→ Hippocampus
What is non declarative memory and what part of the brain is responsible for it?
→ Procedural memory (motor skills, habits)
→ Striatum
What 2 things come under classical conditioning?
→ Skeletal musculature (cerebellum)
→ Emotional responses (amygdala)
What is working memory?
→ Temporary storage that lasts seconds
What is short-term memory?
→ Facts and events are stored in short-term memory
→ Subset are converted to long-term memories
What is long-term memory?
→ Recalled months or years later
Where can sensory information go?
→ Long or short-term memory
What are the functions of the pre frontal cortex?
→ Self awareness
→ Capacity for planning and problem solving
Describe the delayed response task
→ place food in one of two wells
→ put a screen between the monkey and the wells
→ after a delay the screen is lifted
→ the monkey has to remember where the food is
What is associated with the visual cortex?
→ Lateral intraparietal cortex
What is an engram?
→ a collection of neurons that are responsible for the storage of a memory
What is the substrate where a memory is going to be stored?
→ A group of neurons that have reciprocal connections
Describe how an engram is formed
→ An external stimulus is presented
→ Activation of the cell assembly occurs
→ The combined activity creates a network that continues activation even after the stimulus has been removed
→This results in strengthening of certain connections between certain neurons
→ The strengthened connections of cell assembly contain the engram for the stimulus
→ even after learning partial stimuli lead to a whole representation of the stimulus
What is a Hebbian modification?
→ Strengthens the reciprocal connections between neurons that are activate at the same time
Where is the hippocampus located?
→ In the medial lobes
What kind of information comes to the hippocampus?
→ Sensory information
What does the hippocampus do with the information it receives?
→ Sensory information comes in
→ It is sent to the cortical association areas
What kind of tissues are capable of forming engrams?
→ Any neuronal tissue
What is the output pathway of the hippocampus?
→ the fornix
Where does the fornix output to?
→ The thalamus and the hypothalamus
What does the thalamus act as?
→ The post office sorting room for the brain
What does the hippocampus feed back to and why is this important?
→ Feeds back to the cortical areas
→ Important for consolidation
Describe the pathway that sensory information takes
→ Sensory information goes to the cortical association areas
→ Parahippocampal and rhinal cortical areas
→ Hippocampus
→ Fornix
→ Hypothalamus and thalamus
What is amnesia?
→ Serious loss of memory and/or ability to learn
What are the 5 causes of amnesia?
→ Concussion
→ Chronic alcoholism
→ Encephalitis
→ Brain tumour
→ Stroke
What is retrograde amnesia?
→ Severe decrement in memories that they have before the trauma
What is anterograde amnesia?
→ Inability to form memories after the trauma
What happened to Henry Molaison?
→ The surgeon removed his medial temporal lobes
→ lost the ability to make new long term memories
Why was Henry Molaison able to learn new motor skills?
→ Hippocampus was removed - declarative memory
→ his non declarative memory - striatum - was still intact
How does a Morris water maze work?
→ Submerged platform in a wading pool
→ let mouse find the platform
→ make the water cloudy
→ let mouse find the platform again
When do place cells fire?
→ When animals are in certain areas after habituation
What are the 2 models of memory consolidation?
→ Standard model
→ multiple trace model
What is the standard model of memory consolidation?
→ Information from neocortex areas associated with sensory systems are sent to the medial temporal lobe for processing
→ synaptic consolidation - within the hippocampus
→ post consolidation - the hippocampus is not necessary
What is the multiple trace model?
→ Hippocampal involvement is continued
→ multiple memory traces
→ Pathways can be continually modulated by continued experience
What is synaptic plasticity?
→ Biological process by which specific patterns of synaptic activity results in changes in synaptic strength
What does the model of distributed memory show?
→ Instead of three individual responses by three different neurons when you see 3 faces
→ there are changes in all 3 neurons when you see 1 face
Describe the trisynaptic circuit
Information flows from entorhinal cortex, via performant path to the dentate gyrus
Mossy fibres originate from dentate gyrus and synapse upon pyramidal neurons in CA3 hippocampal region
Axons from CA3 (Schaffer collaterals) synapse upon pyramidal neurons in CA1 hippocampal region
What kind of stimulation is needed for long term potentiation?
→ High frequency rapid stimulation
What receptors are located on the CA1 neurons?
→ Glutamate
→ NMDA and AMPA
Describe how long term potentiation works in CA1 neurons
→ AMPA receptors get stimulated
→ CA1 neurons gets depolarised
→ NMDA receptors open → Ca2+ floods in → Calmodulin kinases are activated → AMPA responsivity is increased → more AMPA receptors added onto the post - synaptic membrane (CA1). → more responsive CA1
What are the physiological changes in the dendritic spines after long term potentiation?
→ They swell because there are more receptors
What is the role of lateral intraparietal cortex?
response in delayed-saccade task
When is the greatest firing in the delayed-saccade task?
delay period
