Science Section 4 Flashcards
What is synaptic plasticity?
the ability of synapses to strengthen
or weaken over time in response to changes in their
inputs
True or false. Synaptic strength is fixed.
False
What are monocular deprivation experiments?
an experimental manipulation that deprives one eye of normal vision in order to study changes in development
Can a short period of monocular deprivation change the structure of the synapses and dendrites seen in layer 4C of V1?
Yes
Critical period
limited periods of time when an aspect of brain development is particularly sensitive to inputs from the external environment
What is whisking?
When rodent whiskers are moved back and forth via little muscles in the skin to scan the environment
Barrel field
an area of a rodent’s primary somatosensory cortex representing the touch or somatosensory inputs of each of their whiskers
Phantom limb syndrome
a condition in which patients experience sensations in a limb that does not exist due to the connections from the periphery to the brain remaining in place after amputation
Phantom sensation is a result of ____
The sensations often result from the stimulation of the skin regions whose cortical representations border that of the missing body part.
What is the storage of information over time called?
Memory
According to Santiago Ramon what does learning require?
the formation of new connections between neurons
What is habituation?
learning to ignore stimulus that has no meaning
True or False? The brain stops changing and adjusting to the environment after the critical period.
False. The brain never stops changing but it does become less plastic as the result of aging
Describe Eric Kandel’s experiment to study memory using a sea slug (Aplysia californica)
He primed the sea slug to not react to a stimulus poking its underbelly as it no longer saw the stimulus as harmful. He found that the neurons would still fire the same action potential as they did prior to learning but it had a smaller impact on the postsynaptic cell (aka synaptic weakening, less responsive). When the situation was reversed, the neurons has a larger response (increase on neurotransmitter release and expansion of the synapse surface area was responsible)
What is sensitization?
strengthening of the behavioral response in response to stimulation that is harmful
What do scientists use to record electrical activity
electrophysiological recordings
What is LTP? (long term potentiation)
strengthening of a synapse that is usually based on changes in the postsynaptic receptors.
How long does LTP last
for weeks in living mammals and can potentially last for an entire lifetime.
What is responsible for condensing and consolidating memories
the hippocampus
what is the signal that can cause AMPA receptors to be removed from the postsynaptic membrane,
called long-term depression or LTD
What is the mechanism (process) for the short term sensitization of the gill withdrawal reflex, in regards to Kandel’s experiment with sea slugs?
1). Sensory neuron receives the shock stimulus 2). Interneurons bringing that signal to the next siphon sensory neuron releases serotonin 3). The serotonin binds to GPCRs in the axon terminal to stimulate the production of cAMP (second messenger) 4). Activated by cAMP, protein kinase A (PKA) phosphorylates several proteins and potassium channels 5). The K+ channels now have much more delayed time to open during action potentials which allows there to be a greater amount of Ca+ channels to open in the terminal 6). This extends exocytosis and increases amount of glutamate that is released onto the motor neuron
Under normal synaptic transmission what is released
Glutamate it binds to postsynaptic AMPA receptors
LTP is linked to?
Memory storage, especially with the hippocampus
How do researchers use electrophysiological recordings to measure the strength of a synapse and how it changes based on experiment?
They record the membrane potential of the presynaptic and postsynaptic neurons before and after a learning event