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
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?
→ Input from the entorhinal cortex next to the hippocampus
→ this comes into the perforant pathway
→ synapse onto granule cells
→ Granule cells synapse further onto Schaffer collaterals
→ they synapse onto CA1 pyramidal neurons
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 dendrites after long term potentiation?
→ They swell because there are more receptors
