58211
Description
Mind Map by n.c.wetmore, updated more than 1 year ago
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Created by n.c.wetmore
over 11 years ago
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Single-Cell Mech of
Invertebrate Beh Change
- Aplysia as an Experimental Animal
- Aplysia
- marine invertebrate
related to common
slug
- popular animal for studies
of physiology of learning
- compared to
vertebrates it has
fewer neurones,
many large and
easy to study
- Unlike vertebrates, aplysia neurones are
virtually identical from one individual to
another so diff INV can study properties of
same neurone
- Unlike vertebrates, aplysia neurones are
virtually identical from one individual to
another so diff INV can study properties of
same neurone
- marine invertebrate
related to common
slug
- commonly studied
behaviour:
withdrawal response
- if someone touches the siphon, mantle or gill of
aplysia, it vigurously withdraws irritated struture
- INV traces neural path
fro touch receptors to
motor neurones that
direct response.
- Using this neural pathway, INV studied
changes in behaviour as a result of
experience.
- Using this neural pathway, INV studied
changes in behaviour as a result of
experience.
- INV traces neural path
fro touch receptors to
motor neurones that
direct response.
- if someone touches the siphon, mantle or gill of
aplysia, it vigurously withdraws irritated struture
- Aplysia
- Habituation in Aplysia
- Habituation
- decrease in response to a stimulus that's
presented repeatedly and accompanied by no
change in other stimuli
- if clock chimes every hour, you respond less and less.
- if clock chimes every hour, you respond less and less.
- decrease in response to a stimulus that's
presented repeatedly and accompanied by no
change in other stimuli
- Repeated stimulation of Aplysia's gills with
brief jet of seawater, withdraws at first but
after repetition, stops responding.
- Decline in response is not due to
muscle fatigue because after habituation,
direct stimulation of motor neurone
produces full-size muscle contraction
- Rule out changes in sensory neurone
- Sensory neurone still gives full, normal
response to stimulation but fails to excite motor
neurone as much as before
- Kupfermann et al (1970)
- Kupfermann et al (1970)
- Sensory neurone still gives full, normal
response to stimulation but fails to excite motor
neurone as much as before
- habituation in Aplysia
depends on change in
synapse between sensory
neuron and motor neuron
- Decline in response is not due to
muscle fatigue because after habituation,
direct stimulation of motor neurone
produces full-size muscle contraction
- Habituation
- Sensitization in Aplysia
- the experiencing of unexpected,
intense pain, temporarily react
more strongly than usual to other
strong, sudden stimuli
- sensitisation
- increase in response to mild stimuli
as result of exposure to more intense
stimuli
- A strong stimulus almost anywhere
on Aplysia's skin intensifies a later
withdrawal response to a touch
- A strong stimulus almost anywhere
on Aplysia's skin intensifies a later
withdrawal response to a touch
- increase in response to mild stimuli
as result of exposure to more intense
stimuli
- sensitisation
- INV traced sensitisation to changes at identified synapses.
- through stimulation on skin excites facilitating interneuron
that releases serotonin (5-HT) onto presynaptic terminals
of many sensory neurons
- serotonin blocks potassium channels
in these membranes
- Results in after later action
potentials, membrane takes longer
than usual to repolarize
- Therefore, presynaptic
neurone continues
releasing its NT for longer
than usual
- Therefore, presynaptic
neurone continues
releasing its NT for longer
than usual
- Results in after later action
potentials, membrane takes longer
than usual to repolarize
- repeating this process causes
sensory neurone to synthesise new
proteins that produce long-term
sensitisation
- serotonin blocks potassium channels
in these membranes
- research shows how it's possible to
explain one example of behavioural
plasticity in terms of molecular events
- Later studies explored
mechanisms of classical and
instrumental conditioning in Aplysia
- Later studies explored
mechanisms of classical and
instrumental conditioning in Aplysia
- through stimulation on skin excites facilitating interneuron
that releases serotonin (5-HT) onto presynaptic terminals
of many sensory neurons
- the experiencing of unexpected,
intense pain, temporarily react
more strongly than usual to other
strong, sudden stimuli
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