Lecture 7

Question 1

What do recordings on a single-channel level tell you?

Answer 1

Everything about the receptors

Question 2

What happens if the membrane potential is 0?

Answer 2

The cell dies

Question 3

Patch-clamp technique

Answer 3

Electrode with an opening at the end. Patch the cell, then clamp it. Measure the resistance of the electrode, when you clamp it to the cell the resistance is big –> Gigaseal. Simple patch clamp studies a single channel (if lucky)

Question 4

Whole cell patch clamp

Answer 4

Apply sucking and disrupt the membrane: can study all channels of the cell

Question 5

Voltage clamp measures…

Answer 5

Current in the cell

Question 6

V=

Answer 6

Current x Resistance

Question 7

In voltage clamp if Vm is not the command potential you have to …

Answer 7

Inject current, to bring Vm to the command potential

Question 8

With voltage clamp you record

Answer 8

The sum of all the individual channels’ opening (if 2 channels then 2 levels, etc.)

Question 9

Current clamp measures …

Answer 9

Voltage

Question 10

How does noradrenaline modulate the membrane potential?

Answer 10

Adds +5 mV to it and enhances the number of spikes - studied with a current clamp in

Question 11

Can you have LTP at room temperature?

Answer 11

No

Question 12

Tetrodotoxin (TTN)

Answer 12

Voltage-dependent Na+ channel blocker

Question 13

Evoked potentials

Answer 13

Potentials from cell-populations

Question 14

In the tracer labs we figured out …

Answer 14

What projects to the nucleus accumbens

Question 15

Why do you have jitter in the signal when you stimulate basolateral amygdala and record nucleus accumbens?

Answer 15

Because the neurotransmitter is pushed out of the presynaptic terminal and diffuses (at the synapse)

Question 16

Where do amygdala axons project to in the nucleus accumbens?

Answer 16

To the ventrolateral part (below the AC) + to the other ventral lateral part together with the hippocampus

Question 17

Where are the neurons in NA that respond to hippocampus stimulation?

Answer 17

Medial and lateral NA (but more to the outer edge)

Question 18

Where do you have to stick your electrodes if you are interested in motivated behaviour?

Answer 18

To the NA cells that respond to both amygdala and hippocampus stimulation

Question 19

What do you do with optogenetics?

Answer 19

Optic stimulation. You can depolarize (blue light) and hyperpolarize (yellow light) a cell using light.

Question 20

What receptors does optogenetics use?

Answer 20

Light sensitive algae receptors

Question 21

Stimulation of nucleus accumbens is …

Answer 21

Addictive

Question 22

DBS applications in humans

Answer 22

In PD patients, Tourette’s, epilepsy

Question 23

DBS of which structure is very effective?

Answer 23

Subthalamic nucleus (drives the basal ganglia system)

Question 24

Components of DBS

Answer 24

Electrodes in the brain (STN), on and off switch in chest, remote control for the on and off switch

Question 25

What are the light-sensitive receptors that can depolarise cells used in optogenetics called?

Answer 25

Channelrhodopsine2

Question 26

What are receptors that can hyperpolarize cells and are light sensitive called?

Answer 26

Halorhodopsine

Question 27

How are the light-sensitive receptors put in mice?

Answer 27

The gene that encodes the protein is put in a virus and the mouse’s brain is then infected with this virus. The gene encoding the protein will be expressed in some cells by the appearance of the light-sensitive channels in the membrane of the neuron.