1.5 - Learning Flashcards
who was Wilder Penfield?
neurosurgeon mapping motor, sensory, language functions of cerebral cortex for patients undergoing surgery for epilepsy
what did Wilder Penfield find?
on rare occasions, electrical stimulation of ‘temporal lobes’ produced an ‘experiential response’ (coherent recollection of an earlier experience)
who was Henry Gustav Molaison
27 year old man who suffered from untreatable seizures (recognised as one of most important patients in history of brain science)
what happened to Henry Gustav Molaison after surgery?
(medial temporal lobes removed bilaterally)
- seizures reduced but also major deficits to memory systems
classes of memory (2)
- non-declarative memory (implicit memory)
- ‘skills’ - declarative memory (explicit memory)
- ‘knowledge’
Non-declarative (implicit) memory (2)
- memory recalled unconsciously
- training of reflexive, motor and perceptual skills
brain areas involved in non-declarative memory (5)
- neocortex
- striatum
- amygdala
- cerebellum
- reflex pathways
declarative (explicit) memory (2)
- memory about objects, people, places, events and what info actually means
- highly flexible - bringing together associations between multiple elements
brain area involved in declarative memory
medial temporal lobe
types of neuronal connection plasticity (4)
- biochemical
- neurotransmitters etc - structural
- synapses/connections in neurons - biophysical
- modify synaptic connections - genetic
- genes related to synaptic/neuronal activity
(go more in depth - research)
simple forms of implicit memory
look at one note
habituation
reduced response to repeated non-noxious stimulus
aplysia gill withdrawal reflec
gill (respiratory organ) withdrawn in response to a tactile stimulus to the siphon
short term cellular basis of habituation
reduced number of synaptic vesicles released (fewer functional vesicles)
how much can structure change in long term habituation?
number of synapses can half
sensitisation
increased response to non-noxious stimulus when following a noxious stimulus
sensitisation in Aplysia
gill withdrawal response can be sensitised by an electrical tail shock
short term sensitisation in Aplysia (3)
- 1 tail shock
- enhanced gill-withdrawal
- lasts several minutes
long term sensitisation in Aplysia (3)
- 5+ tail shocks
- enhanced gill withdrawal
- lasts days to weeks
long term cellular basis of habituation
structural changes (fewer synapses)
long term habituation in Aplysia (gill withdrawal reflex) (2)
- 4 x 1-10 trials separated
- lasts up to three weeks
(stimulus non-harmful, gradually habituation occurs, reduced response)
short term habituation in Aplysia (gill withdrawal reflex) (2)
- 1-10 trials
- lasts a few minute
(stimulus non-harmful, gradually habituation occurs, reduced response)
Cellular basis of sensitisation in Aplysia
sensory neuron in tail responds (when shocked) sends neurotransmitters via facilitating neuron to same motor neuron effected by siphon sensory neuron
effects of PKA in sensory neuron response to facilitatory neuron neurotransmitters (3)
- PKA changes properties of K+ channels (reduced efficiency prolonging A.P)
- PKA changes vesicles (increased releasability meaning more bind and more neurotransmitters -> motor neuron)
- PKA acts at nucleus of sensory neuron (upregulates genes producing proteins that bind creating new synapses and ion channels)
