Last Chapter Flashcards
How do housing conditions affect brain development in animals?
There are three housing conditions which involves a standard condition and an impoverished condition and an enriched condition. Enriched conditions resulted in
- Heavier & thicker cortexes
- Enhanced cholinergic activity
- More dendritic branches and spine on cortical neurons
- Larger cortical synapses
- More neurons in the hippocampus
- Enhanced recovery from brain damage
Define neuroplasticity and provide examples.
AKA Neural plasticity. Is the ability of the nervous system to change in response to experience or the environment.
- Changes may be presynaptic, postsynaptic, or both and are measured physiologically.
- Metabotropic receptors can initiate signals within the neuron.
- New learning and memory formation can involve formation of new synapses or birth of new neurons
What are the four measured ways that neuroplasticity can be measured?
- Increased neurotransmitter release
- Inactivation of the transmitter is decreased
- A greater effect due to changes in receptors
- Influence by other neurons
Also: New synapses may form for long term memories or die back. Training brings about reorganization. New synapses can form and can be shifted into a synaptic input.
What brain changes were observed in London taxi drivers and what control group and confounding factors were observed in this study? ( Don’t have confounding factors.)
The drivers can navigate complicated street layouts without a GPS, due to changes in hippocampus of experienced drivers. A good control group would be walkers or people who cannot drive. synaptic plasticity and frequency of neurons being stimulated.
Spatial knowledge is associated with pattern of hippocampal matter volume.
Define Habituation
Habituation is a form of non-associative learning which is learning that involves only one stimulus.
Habituation is not a result of these two factor:
- Failure of the sensory system to detect the stimulus
- Failure of the motor system to respond.
Explain the synaptic changes underlying short-term habituation
Less transmitter is released by the sensory neuron produces the short term habituation. It is chased by synaptic changes between the sensory cell the siphon and the motor neuron that retracts the gill.
Explain the synaptic changes underlying long-term habituation.
Habituation paradigm over a series of days. Each successive day the animal habituates faster than it did before. This represents long term habituation and it results from fewer synapses.
Describe habituation in Aplysia.
A decrease in response to a repeated stimulus.
- A squirt of water on its siphon causes it to retract its gill.
- After repeated squirts, the animal retracts the gills less.
What is the Hebb rule?
” Cells that fire together wire together.” Hypothesis: The cellular basis of learning involves strengthening of a synapse that is repeatedly active when the postsynaptic neuron fires. Repeated experiences cause higher frequency action potential, which causes high frequency action potential which causes more glutamate to be released ( tetanus.)
Where does long-term potentiation occur in the brain?
The denate gyrus. LTP occurs at the pathways in the hippocampal formation. Hippocampus and DG. As well in other locations.
What is the experimental setup for studying LTP in the hippocampus?
Electrodes are placed within the perforant path so that researches can stimulate a group of presynaptic axons and then immediately record the electrical group of postsynaptic neurons ( dentate gyrus.)
How do excitatory post- synaptic potentials ( ESPS’s) change during LTP induction?
When a brief high-frequency burst of electrical stimuli ( tatanus) is applied to presynaptic cells, it causes them to produce a high rate of action potentials, the response of the post synaptic neurons change. It can last for weeks. Normal low-level activation of the presynaptic cells produces stable and predictable EPSP’s
How long does ATP last?
It can last for weeks or more.
What are the key properties of NMDA & AMPA receptors involved in LTP?
On the postsynaptic membrane they are both permeable to NA+.
Why do AMPA receptors remain open longer in LTP?
AMPA receptors remain open longer because there’s more glutamate which causes influx of NA+
