Main points
- Resting potential
- Equilibrium point (e.g., attractor state)
- Balance of forces (diffusion/voltage)
- Combined effects on multiple ions
Cellular Neuroscience II
PSY 511.003
2024-02-01
Prelude
Announcements
- Exercise 04 assigned
- Next Wednesday, February 7, Exercise 03 write-up due.
Last time…
What maintains the ion concentration gradients in the neuron (and other cells)?
What do gradients enable?
What direction does information typically flow in a neuron?
What type of glial cell creates myelin around axons in the central nervous system?
Today’s topics
- Resting potential review
- Cellular neuroscience II
- Action potential
- Synaptic transmission
Resting potential
Potential means…
- Electrical potential (voltage)
- Current flows (ions move)
- More current can flow if…
- Conductance changes (ion channels open)
Why we care
- Fast signalling (faster than diffusion)
- From one part of body to another
Outward \([K^+]\) flow
- Down concentration gradient
- Charges membrane like a capacitor
Small \([Na^+]\) flow
- Channels for \(Na^+\) not especially permeable
- \(Na^+\) flows ___________ (Why?)
- Makes total voltage across (membrane potential) more [positive/negative] (Why?)
- Membrane potential = \(\Sigma\) of all ion effects
Goldman-Hodgkin-Katz equation
Party metaphor
- Annie (\(A^-\)) was having a party.
- Used to date Nate (\(Na^+\)), but now sees Karl (\(K^+\))
- Hired bouncers called
- “The Channels”
- Let Karl and friends in or out, keep Nate out
- Annie’s friends (\(A^-\)) and Karl’s (\(K^+\)) mostly inside
- Nate and friends (\(Na^+\)) mostly outside
- Claude/Claudia (\(Cl^-\)) tagging along
Wikipedia
Action potential
Link to resources/cells
Synaptic transmission
Link to resources/cells
- Action potential
- Short (in time), discrete message
- Can propagate quickly
- Triggers neurotransmitter release
Next time…
- Neurochemistry
- Neurotransmitters
- Hormones
- Neurocomputing
Resources
References
PSY 511 Spr 2024