Lecture 7: Neurophysiology Flashcards
log time
time of phenomenon
in brain studies: ms-s
log size
brain area to look at
synapse, dendrite, layer neuron, column, map, brain etc
What are different levels at which you can study brain?
single channel level, single cell level, population level
single channel level
single receptor information (effects of acetylcholine)
single cell level
figure out what cell is doing in relation to other effects
population level
for example: hippocampus role
from where we record activity in single channel/cell level?
soma! not so much dendrites
how can we record from cells?
membrane ensures potential difference between inside and outside
membrane potential
current flows by the virtue of potential difference (between outside and inside of the cell), negative inside with respect to outside
what maintains membrane potential?
sodium-potassium pump (dependent on ATP)
what are channel types?
active transporters and ion channels
active transporters
actively move selected ions against concentration gradient; create ion concentration gradients
ion channels
allow ions to diffuse down concentration gradient, selectively permeable to certain ions
patch clamp technique
used to study electrical properties of excitable cells and ion channels
enables isolating patch of membrane through which different currents pass
2 types: voltage clamp, current clamp
voltage clamp
clamping (controlling) the voltage across the membrane and measuring current passing through it
current clamp
clamping (controlling) the current across the membrane and measuring the voltage passing through it
what is a difference between current and voltage?
Voltage is the force that makes electrons flow. It’s a difference in potential energy between two different points in a circuit. = CAUSE
Current: Current is the rate of the flow of electrons. = EFFECT
How to most easily identify single channel of interest in patch clamp technique?
apply substance to the patch of membrane to which receptors in channel are the most responsive to
What happens when you apply benzodiazepines/barbiturates?
increase frequency of GABA channels opening - more inhibition - sleeping agent
why barbiturates are dangerous?
because they open -by themselves- all GABA channels - may be deadly