Term
| what is the role of inhibition? |
|
Definition
| drives a cell away from firing an action potential (essentially, the opposite of excitation) |
|
|
Term
| the majority of fast inhibition in the brain comes from _______ receptors |
|
Definition
|
|
Term
|
Definition
| inhibitory counterpart to glutamate |
|
|
Term
| GABA (gamma aminobutyric acid) = produced by ________ |
|
Definition
| neurons using GAD (glutamate amino decarboxylase) to kick a CO2 out of glutamate |
|
|
Term
|
Definition
| packages GABA from cytosol into vesicles |
|
|
Term
|
Definition
| makes GABA from glutamate |
|
|
Term
|
Definition
| packages GABA into vesicles to be able to be used as a neurotransmitter |
|
|
Term
| ionotropic (GABA(A)) GABA receptors |
|
Definition
| when GABA binds to GABA(A) receptors, chloride can flow into the cell to hyperpolarize it quickly |
|
|
Term
| metabotropic (GABA(B)) GABA receptors |
|
Definition
| GPCRs that bind GABA whose G proteins couple to potassium channels to activate them & allow positive charge to flow out of the cell |
|
|
Term
| 4 psychoactive compounds that can bind to ionotropic GABA receptors |
|
Definition
1. barbiturate
2. benzodiazepine
3. alcohol
4. neurosteroids |
|
|
Term
| how do allosteric modulators of ionotropic GABA receptors affect their activity? |
|
Definition
| don't change how the channels behave BUT they change the strength/duration of chloride currents into the cell |
|
|
Term
| what is the implication that ionotropic GABA receptors are pentamers? |
|
Definition
| 5 different subunits that can all be affected differently by different allosteric modulators |
|
|
Term
|
Definition
|
|
Term
| neuroscience version of Ohm's Law |
|
Definition
|
|
Term
| equation to find current (I) |
|
Definition
|
|
Term
|
Definition
| V = (g(ion1)(E(ion1)) + g(ion2)(E(ion2)))/(g(ion1) + g(ion2)) |
|
|
Term
| what does it mean that AMPAR EPSPs summate to depolarize cell? |
|
Definition
| the more AMPA open = greater AMPA conductance = cell is able to depolarize enough to overcome leak potential & get to spike threshold --> AP! |
|
|
Term
| what is the chloride channel influence on the GHK equation to try to clamp the cell around -65 mV? |
|
Definition
| looking at GHK, the conductance of the chloride channels increasing --> divides more from the top value to keep a smaller membrane potential |
|
|
Term
| how does the change in chloride reversal potential as you age contribute to childhood seizures? |
|
Definition
| more ability for runaway cell excitation because chloride potential is also excitatory |
|
|
Term
| how does inhibition affect neuronal communication (2 ways)? |
|
Definition
1. can shunt incoming synaptic signals
2. can cancel action potentials |
|
|
Term
| neurons receive thousands of inputs...some are excitatory, some are inhibitory...neuron must _______ all of these different inputs |
|
Definition
|
|
Term
|
Definition
| inputs coming in close together in time coming from one input source |
|
|
Term
|
Definition
| inputs coming in close together in proximity from multiple input sources |
|
|
Term
| is inhibition simply the negative version of excitation? |
|
Definition
|
|
Term
| when talking about shunting inhibition, we are talking about inhibition mediated by _______ receptors |
|
Definition
|
|
Term
| in a mature nervous system, reversal potential for chloride is usually around ______ |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| what does it mean that an AP is all or nothing? |
|
Definition
| once you pass threshold, you will get an AP |
|
|
Term
| 3 examples of things that can happen when you are below AP threshold |
|
Definition
1. single EPSPs
2. EPSPs can summate
3. inhibitory current |
|
|
Term
| is the sign associated with your driving force (voltage you're at - reversal potential equation) important? |
|
Definition
| not necessarily...thinking more about the absolute value to compare strength of driving forces for different ion species |
|
|
Term
| compare driving force of AMPA vs Cl at spike threshold |
|
Definition
DF(AMPA) = -50 - 0 = -50
DF(Cl) = -50 - (-65) = 15
*clearly this is much less strong than AMPA |
|
|
Term
| when do chloride channels become involved in the GHK equation? |
|
Definition
| when GABA is being puffed onto the cell, chloride channels open |
|
|
Term
|
Definition
| adding a bunch of inputs from one presynaptic terminal in a short amount of time |
|
|
Term
|
Definition
| adding individual inputs from various presynaptic terminals in close physical proximity to one another |
|
|
Term
| what is the main point in how inhibition affects temporal & spatial summation? |
|
Definition
| changes membrane properties (g is the inverse of R) & inhibition increases conductance! |
|
|
Term
| feedforward inhibition is primarily dealing with ________ |
|
Definition
| parvalbumin (PV) GABAergic interneurons |
|
|
Term
| feedforward inhibition circuit |
|
Definition
| same glutamatergic input depolarizes the pyramidal neuron also has a branch that goes to the PV interneuron that releases GABA onto the same pyramidal neuron |
|
|
Term
| 2 things feedforward inhibition is really good at |
|
Definition
1. increasing precision in nervous system
2. orchestrating a large synchrony response across a large population of cells |
|
|
Term
| when you introduce feedforward inhibition & record from a pyramidal neuron --> you see _______ |
|
Definition
| EPSC but also an IPSC that is slightly delayed but much larger |
|
|
Term
| feedforward inhibition precision comes from _______ |
|
Definition
|
|
Term
| temporal window for integration |
|
Definition
| feedforward inhibition is very precise because the pyramidal neuron ONLY has those 3 ms to fire an AP because after that it will be inhibited |
|
|
Term
| what is the implication that the same excitatory input affects pyramidal cell & its inhibitory interneuron? |
|
Definition
| stimulating excitatory input & recording from pyramidal --> monosynaptic excitation --> 3 ms latency --> disynaptic inhibitory current |
|
|
Term
| excitatory input in hippocampus |
|
Definition
|
|
Term
|
Definition
| major projection neurons in the cortex & hippocampus |
|
|
Term
| typical feedforward interneuron |
|
Definition
|
|
Term
|
Definition
| doing the same thing every time |
|
|
Term
|
Definition
| things are happening at the same time |
|
|
Term
| what is the importance of PV targeting multiple pyramidal neurons? |
|
Definition
| it will inhibit them all at the same time --> they will be able to come back "online" at the same time --> will fire at the same time |
|
|
Term
| what is meant by feedforward inhibition can promote firing precision? |
|
Definition
| pyramidal cells will spike pretty much all at the same time |
|
|
Term
| blocking feedforward inhibition has what affect on pyramidal cell firing? |
|
Definition
| much larger range in time when the pyramidal cells fire in response to Schaffer collateral input |
|
|
Term
| different oscillatory patterns are important for various levels of _______ |
|
Definition
| arousal (decreasing oscillation frequency as you go down in arousal) |
|
|
Term
| example of a neurological/neuropsychiatric disease with observed abnormal brain waves |
|
Definition
| schizophrenics have issues with PV interneurons --> abnormal oscillation patterns --> disorganized thoughts |
|
|
Term
| affect of introducing bicuculline or perotoxin & recording from pyramidal cell |
|
Definition
| GABA(A) receptors are blocked by bicuculline & perotoxin --> block FFI --> only have excitatory current when recording from pyramidal cell after stimulating Schaffer collateral |
|
|
Term
| affect of applying NMQX to FFI circuit & recording from pyramidal cell |
|
Definition
|
|
