Tut 3 Flashcards
What is the defintion of a synapse ?
It is a gap where tow neurons exchange chemical messages via neurotrnsmitter !
Where are synapses formed ?
Between:
- Axon and Dendrite
- Axon and cell body
- Axon and Axon
- Dendrite and Dendrite
Where are neurotransmitter hold ?
- in pre synapitc neurons vessicles
What are the main chemicals and what are there functions regarding action potential ?
- Glutamate
- Gaba
- Dopamine
- Either exitatory or inhibitory
How does the exchange between neurons take place ?
- Pre- relases neurotransmitter
2. post collects neurotransmitter via receptors
What is the refraction period ?
- Period where neurons can not fire again
How do synapses geting cleared after the releas of chemicals ?
- interactivation ( Braking neurotransmitter down)
- reuptake (Neurotansmitter gets taken back from presynaptic neuron)
What is so special about the neurotransmitter neuromodulator ?
- modulate activity of large number of neurons
- When there is a memory or learning diseases than there is a decline in the neuromodlaor
What is synaptic plasticity ?
- changes in synapse coactivity
What did Donals Heb say ?
- If two neuons fire often together then they wire together
- hebbian synapses ! (Synapses have learning pattern)
What is the comulative effect ?
- it is a very strong connection between two synpases due to constant co activtaion
What is the basic of Early LTP ?
- last only for few hours or days (functional changes)
- one strong impulse
What is the basic of late LTP ?
- Constant exposure to a stimuli so strong activity - Structural or functional changes
how does Early LTP work ?
- one strong co - activation ! -> magnesium ion is released from NMDA recpetors (not influenced by genes using existing porteins)
- magnesium pops out via high depolarisation due to lots of glutamate/sodium via AMPA receptor
- NMDA is open -> leads to calcium entering the post synapses
- > Calcium binds to clamodulin ->protein kineases -> take out the internalized AMPA receptor to the synaptic cleft
- Not permanent changes !
What is Long term depression ?
A weakining in activity between two neurons
-> need for space u can not store all kind of infomation
How does long tem depression work ?
- Decrease of responsive in post
- Decrease of neurotranistter in pre
- Long term structural changes (regarding neuron or synapse)
What is cellular /synaptic consolidation ?
- process of synaptic and cellular changes (plasticity)
- early LTP functional changes
How does Late LTP work ?
- Due to many co activation the calmodulin/protein kineases go into the nucleus (either IG or late genes expression)
- Kineases activates creb
- creb activates IG can stengthen the protein kineases -> more ampa receptor
- IG can activate LG via RNA proteins
- > Cam form new proteins or synapses
What is system consolidaion?
- it is the change of neurol network which is linked to memory storage (structural changes)
- late LTP
What is the activaion time of LGs and what is the activation time in IG
- within a 3-6 hours LG
- within a few min IG
What is the difference between LG and IG ?
LG:
- produce new proteins
- Needs gene expression
- and many co activation
When does the hippocampus reactivates the teaching patterns ?
- In paticular during sleep but also when u are awake
Where are the place cells located ?
- in the hippocampus (in the temporal lobe, posterior from the amygdala)
What is the role of the hippocampus according to the theory place field?
- Because episodic memoy is allways dependent on spatial context
- Means that hippocampus is allways involved and so it is more than a tutor
- Not involved in semantic memory
- Evidence for MTT theory
What is so special regarding place cells ?
- They depend on place fields and place fields depend on boundaries
What is a neurol chain ?
- Neuron to neuron connection
What is Superordinated circuit ?
- A simple neuronal chain is modulated
by the activity of a third neuron
What is so interesting regading LTP ?
- Not bin proven it is only a paradigm
- Only found in tetanus experiments
