BIO 452 Exam 2 PPT 1

dependent

voltage-______-Membrane properties: physiological properties of a neuron that are as important as synapses in determining neuronal activity and circuit output - usually not represented in diagrams

conditional

voltage dependent membrane properties are ___ (depend on the NT present)

metabotropic

Voltage dependent membrane properties are modified by ____ actions

ion channels

Usually voltage-dependent ionic currents are due to the effects on ____ ______

Intrinsic Oscillation

rhythmic, without

Intrinsic oscillations have ___ membrane potential oscillations ____ rhythmic synaptic input

Intrinsic oscillations

• Rhythmic membrane potential oscillations without any rhythmic synaptic input

• Results from interplay of multiple voltage-gated ion channels

• Useful for heart pacemakers, breathing, autonomic NS

  • Pacing rhythmic activity pattern generated by rhythmically active circuits (brainstem breathing circuit)

No

Is modification of one ion channel enough to make an intrinsic oscillation?

lack, isolated

R15 in Aplysia is the original burster, and still exhibits oscillations when there is a ___ of rhythmic synaptic input and oscillates when ___

Larger

Invertebrate neurons are ____ than vertebrate neurons

Serotonin

In Aplysia, adding ____ made the oscillations more spaced out

Burst

Group of action potentials

TRH

In Guinea pigs, applying ___ creates oscillations

Hyperpolarized

Funny channels open when the membrane is ___

depolarize, Na, K

Funny channels work to ___ the membrane (__ and ___ ions flow in to depolarize even more)

increase

To slow down heart rate, you would want to ___ voltage threshold

voltage

I_{K Ca} is a ____ dependent potassium channel that only works when calcium is present

Spike frequency adaptation

Spike frequency adaptation

• Ability for action potential frequency to decrease during sustained activity

• Usually due to slowly opening current that hyperpolarizes the neuron

• Enables the active phase of a neuron to end its own without the need for an inhibitory synaptic input

• Useful for desensitization to a stimulus

• Same input but action potentials are decreasing over time

Fatigue

Spike frequency adaptation is also called ___

M

In mice: ___-Current is a slowly activating voltage-gated K+ channel

Muscarinic

M channels are ___, or Ach metabotropic channels

slower

Closing M-channels leads to a ___ EPSP

increases, tonic

An M-current blocker ___ seizures and causes ___ firing

decreases

An M-current activator ___ seizures

steady

If you get rid of the M channel, you get ___ firing

Plateau Potential

Plateau Potential

• Prolonged depolarizing response

• Opening of voltage gated channels that close very slowly

• Maintained depolarization usually with action potentials on plateau

• Self-terminates: often due to the slow build-up of a hyperpolarizing current

• Useful for: bladder control and postural muscles

depolarizing

Plateau Potential: prolonged ___ response

hyperpolarizing, IPSP

Plateau Potential: self terminating and usually ends due to a slow build-up of a ____ current or a sudden ____

downstate, transient

A small ____, below threshold, firing is usually a ___ stimulus

crab, turtle

Plateau Potential: The small circuit model is ___ and the large circuit model is ____

Escape from Inhibition

During

An escape from inhibition is the ability to depolarize ____ persisting inhibition

Escape from Inhibition

• Ability to depolarize during persisting inhibition

• Often results from the activation of the H current

• Useful for locomotion and chewing

• Enables neurons to become active even when they are still being inhibited

  • Helps with transitions from inhibited to excited

oscillation

Escape from Inhibition can create an ____

leech

neurogenic heartbeat in a ___ is an example of

Escape from Inhibition

Post Inhibitory Rebound

Post Inhibitory Rebound

• Rapid “rebound” after a period of hyper polarization or synaptic inhibition

• Overshoot of the resting potential and an action potential burst

  • One mechanism: Ih activation was not strong enough for escape from inhibition

• Enables neurons to generate activity in response to inhibition

  • Very common in rhythmic circuits: walking, breathing, chewing

lobster, delayed, mice (mouse)

Small circuit Post Inhibitory Rebound is ___ and they can show ___ Post Inhibitory Rebound due to dopamine

Large circuit example is ___

synaptic

Oscillation due to another neuron is ___

intrinsic

Oscillation due to voltage gated channels or sensitivities is ___