Learning and memory Flashcards
What are the 4 types of memory?
Learning: acquisition of new information
Memory: retention of learned information
Declarative memory (explicit)
- Facts and events – hippocampus, medial temporal lobe, diencephalon
Nondeclarative memory (implicit)
- Procedural memory—motor skills, habits - striatum
What are the Types of Declarative and Nondeclarative Memory?
On image
What are the types of Declarative Memory
Working memory
Temporary storage, lasting seconds
Short-term memories—vulnerable to disruption
Facts and events stored in short-term memory
Subset are converted to long-term memories.
Long-term memories
Recalled months or years later
How do we convert short term memory into long term memory?
Sensory information goes into working memory and short term memory –> consolidation goes into long term memory as time progresses
Find the prefrontal cortex
What is its function?
- Primates have a large frontal lobe.
* Functions of prefrontal cortex: self-awareness, capacity for planning and problem solving
Describe the delayed response task
- Monkey is sat down at a table where there are 2 wells.
- The monkey can see the wells and a food reward is placed in 1 of the wells.
- A screen then comes down between the monkey and the reward for a finite period of time (delayed time).
- The wells are then covered over and the screen is removed (choice period). The monkey can then choose the wells and get the food.
- The monkey needs to retain memory in order to the get the reward.
In prefrontal cortex, neuronal activity spikes during delayed period when it is retaining which well the food reward is in.
Describe the premise of example lateral intraparietal cortex neuron response in delayed-saccade task
Intrapartiel area is located in the back of the brain
Delayed sound task:
1. The monkey is trained to keep eyes fixated on a point on a screen
2. A brief target is then flashed on the screen and a delay in where the target disappears and the fixation remains.
3. The animal is trained to remain fixated on the original point until it disappears.
4. The monkey then looks at the target point
Neuronal activity in intrapartiel region is at its greatest frequency in delayed period
Where are memories stored though?
- External stimulus leads to activation of a neuronal cell assembly
- Reverberating activity continues activation after stimulus is removed
- Hebbain modification strengthens the reciprocal connections between neurones that are active at the same time.
- The strengthened connections of the cell assembly contain the engram for the stimulus
- After learning, partial activation of the assembly leads to activation of the enture representation of the stimulus
Describe the feeds into the hippocampus
Next to the hippocampus:
• Para hippocampal cortex feeds into:
- Perirhinal cortex that’s feeds into:
- Rhinal sulcus that feeds into:
- Entorhinal cortex that feeds into the hippocampus
What is the flow of information through the medial temporal lobe?
Sensory info -> corticol association areas -> parahippocampul and rhinal cortical areas -> hippocampus - > fornix -> thalamus and hypothalamus. Hippocampus feeds back on cortical association areas
What is Amnesia and what causes it?
Amnesia: serious loss of memory and/or ability to learn
Causes: concussion, chronic alcoholism, encephalitis, brain tumor, stroke
What are the 2 types of Amnesia?
Retrograde amnesia: forget things pre-trauma
Antegrade amnesia: learns consolidated memories and cannot create new ones
Describe the morris water maze premise
Morris water maze:
1. A rat is placed in pool with a hidden platform
2. At first the rat swims and finds platform
3. On repeated attempts it will swim straight to the platform, remembering where it is
• Learning Morris water
maze requires hippocampus.
• Place cells fire when animal is in a specific place.
• Place fields dynamic
If you block hippocampus neurotransmitters cant learn maze
Place cells work for specific places
What are the 2 models of memory consolidation?
• Standard model of memory consolidation
o Information from neocortex areas associated with sensory systems sent to medial temporal lobe for processing
o Synaptic consolidation, systems consolidation
o Post consolidation, hippocampus not necessary
• Multiple trace model of consolidation
o Hippocampal involvement is continued
o Multiple memory traces
o Dependent upon synaptic plasticity – ‘the biological process by which specific patterns of synaptic activity result in changes in synaptic strength’
What is a distributed memory?
The changes in neuronal response can be explained by synaptic plasticity. The trisynoptic circuit of the hippocampus if often used in studies of this phenomenon.
