Psyc201 Test 1, Week 3

Question 1

Resting Membrane Potential

Answer 1

The electrical potential across a neuron’s membrane when it is at rest, typically around -70 mV (inside negative).

Question 2

Depolarization

Answer 2

A change in membrane potential that makes the inside of the cell less negative (more positive).

Question 3

Hyperpolarization

Answer 3

A change in membrane potential that makes the inside of the cell more negative.

Question 4

Ion Channels

Answer 4

Proteins in the cell membrane that allow specific ions to pass through.

Question 5

Sodium (Na+) Distribution

Answer 5

Higher concentration outside the cell.

Question 6

Potassium (K+) Distribution

Answer 6

Higher concentration inside the cell.

Question 7

Action Potential Threshold

Answer 7

The membrane potential (-60 mV) at which voltage-gated Na+ channels open.

Question 8

Na+ Influx

Answer 8

The rapid movement of sodium ions into the cell during depolarization.

Question 9

K+ Efflux

Answer 9

The movement of potassium ions out of the cell during repolarization.

Question 10

Na+/K+ Pump

Answer 10

Actively transports 3 Na+ ions out and 2 K+ ions into the cell to restore resting potential.

Question 11

Action Potential Summary

Answer 11

Depolarization, Na+ influx, repolarization, K+ efflux, resting potential restoration.

Question 12

Refractory Period

Answer 12

The period after an action potential when another action potential cannot occur.
Absolute Refractory State – Not responsive at all (about 1 ms)
Relative Refractory State – Only responsive to strong stimuli (about 2 -4 ms)

Question 13

Cocaine’s Effect on Neurons

Answer 13

Blocks voltage-gated Na+ channels, preventing action potentials.

Question 14

Unmyelinated Neurons

Answer 14

The action potential travels continuously along the axon.
This is (relatively) slow (up to 10 m/s).

Question 15

Myelinated Neurons

Answer 15

In myelinated neurons, the action potential jumps from one Node of Ranvier to the next. This is much faster (up to 100 m/s).
This is referred to as “Saltatory Conduction”

Question 16

Synaptic Communication Process

Answer 16

• Neurotransmitters are synthesized in the neuron and stored in vesicles.
• Upon the arrival of an action potential voltage gated Ca2+ channels open.
• This ultimately leads to neurotransmitter vesicles fusing with the cell membrane, releasing the neurotransmitter into the synaptic cleft.
• The neurotransmitter then diffuses in the synapse and will eventually attach itself to specific receptors (proteins) on the postsynaptic cell.
• This interaction induces a change in the postsynaptic potential (EPSP or IPSP).
• The neurotransmitter only binds shortly to the receptor.
• Once it is released it can diffuse away, be metabolized (broken down) or taken back up into the presynaptic terminal (recycling).

Question 17

Vesicles

Answer 17

Store neurotransmitters in the presynaptic terminal.

Question 18

Reuptake

Answer 18

Reabsorption of neurotransmitters into the presynaptic terminal.

Question 19

GABA

Answer 19

Inhibitory neurotransmitter, involved in anxiety regulation.

Question 20

Glutamate

Answer 20

Excitatory neurotransmitter, involved in learning and memory.

Question 21

Dopamine

Answer 21

Neurotransmitter involved in reward, motivation, and motor control.

Question 22

Serotonin

Answer 22

Neurotransmitter involved in mood, sleep, and appetite.

Question 23

Cotransmission

Answer 23

Release of multiple neurotransmitters from a single neuron.

Question 24

Ionotropic Receptors

Answer 24

Fast-acting receptors that directly open ion channels.
– Example Glutamate
* Influx of Na+ - ions
* Excitatory – Relevant for learning and memory
– Example GABA
* Gamma amino butyric acid
* Influx of Cl- - ions
* Inhibitory – Relevant for anxiety (reduced GABA)
Diazepam prolongs the opening of the GABA receptor and helps with my anxiety.
Almost all drugs used for mental health problems influence this communication

Question 25

Metabotropic Receptors

Answer 25

Slower-acting receptors that trigger intracellular signaling cascades (G-protein coupled receptors).
Many drugs such as morphine and antipsychotics act on metabotropic receptors.

Question 26

Neurotransmitter Inactivation

Answer 26

• After a neurotransmitter binds it rapidly detaches from the receptor.
• This can be followed by:
• Renewed binding
• Diffusion away from the synapse (neuropeptides)
• Metabolic breakdown and inactivation
• Reuptake in the presynaptic terminal

Question 27

Long-Term Potentiation (LTP)

Answer 27

Strengthening of synaptic connections through repeated stimulation.

Question 28

Antagonist

Answer 28

A substance that blocks or inhibits the action of a neurotransmitter.

Question 29

Agonist

Answer 29

a substance that mimics the actions of a neurotransmitter to produce a response when it binds to a specific receptor

Question 30

AMPA, NMDA receptors (LTP)

Answer 30

• glutamatergic neurons
• These neurons have two receptors AMPA and NMDA, with the latter being blocked under normal circumstances.
• Strong activation of the AMPA receptor removes the block and allows the influx of Ca2= ions. This sets in motion a cascade of protein activations leading to more receptors and large synapse surfaces ultimately leading to a stronger synaptic communication.

Question 31

Performance in the Stroop Color Word Test is determined by multiple aspects of cognition:

Answer 31

• Visual perception
• Language processing
• Attentional control
• Executive functioning
• Inhibitory control

Question 32

Dorsolateral Prefrontal Cortex

Answer 32

Mostly active during preparation: Attentional control

Question 33

Anterior Cingulate Cortex

Answer 33

During Incongruent Phase:;
Error monitoring

Question 34

Brain Regions in Stroop Test

Answer 34

Multiple regions, with critical involvement of the prefrontal cortex.