what is the engram?
a unit of cognitive information embedded in a physical substance
how did karl lashley test for the engram?
damaged certain regions of a rats brain to see if it damages its memory of how to get through a maze
he found that the larger the area of damage, the more errors the rat made when going through the maze
with this he coined the law of mass action or equipotentiality, meaning that memory loss is a result of how much of the whole brain is damaged and not due to to loss of any particular area
outline Korsakoffs syndrome
korsakoffs syndrome causes profound memory loss and involves a small lesion to a tiny part of the brain called mamilary bodies
outline the case study of HM
- HM had profound amnesia
- this arose due to damage in his brain that occured in surgery to treat epilepsy
- his medial temporal lobe was removed
- this suggested that the hippocampus was a key structure in declarative memory
what is anterograde amnesia?
inability to form memories
what was milners findings about HM and procedural memory?
- HM was able to improve at skills requiring procedural memory (mirror drawing task) how ever he could not remember ever having practiced them
- this suggests that the medial temporal lobe structures that were removed seem only to be involved in consciously available declarative memory
what is the difference between declarative and non declarative
declarative/explicit = consciously available non-declarative/implicit= not consciously available
what are two types of declarative memory?
semantic
eposidic
what are two types of non declarative memory?
associative (e.g conditioning) non associative (e.g habituation)
what part of the brain is motor learning involved in?
cerebellum
what part of the brain is habituation and sensitisation involved in
reflex pathways and neocortex
what part of the brain does emotional learning often involve?
amygdala
why is alplysia californica used in neuroscience research
- it is a marine mollusk
- it has enormous neurons that are easily accessible to electrodes
- studies of habituation in this organism found that the animal stopped producing an electrical response to a waterjet over time. this habituation was found to be because of reduced transmitter release from the presynaptic sensory neuron
what are 5 reasons for using the mouse as an animal model of memory and learning
- mammal so closely related to humans
- produces large litters
- short gestation time
- matures quickly
- ameaneable to genetic engineering
how can we use genetic engineering to study memory in mice?
- candidate molecular mechanisms in learning and memory can be enhanced or suppresed
- temporally and spatially conditional knockdown systems can be used
- cell type and activity dependent markers can be expressed
- opto-genetic/chemo-genetic actuators can be expressed
- diseases with known genetic cause can be modelled
what is second order conditioning
e.g rewarding an animal with food and then training them to associate this food reward with a click and then using the click to train animals
how are proteins related to memory consolidation?
New proteins are expressed to support memory consolidation
if we block protein translation in certain situations we can block lasting memory
if we block transcription we can also block long lasting forms of synaptic plasticity and memory
blocking these processes doesnt block short term memory
delivering a protein synthesis inhibitor in rats stopped them from developing long term memory relating to their fear conditioning
delivering the same inhibitor later during retrieval of the memory then led to the memory erasing
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topic 1 (brain cells and types)29
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topic 1 (brain cells SUBCELLTYPES)20
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topic 1 video 3 (communication between cells)3
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READING54
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Topic 2 electrical signals40
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Topic 3 (chemical synapses)32
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Topic 4 (neurotransmitters and receptors)72
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topic 5 (neurotransmitters in health and disease)31
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topic 6 (neuroactive drugs)45
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topic 746
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topic 8 neuroplasticity24
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topic 917
