Unit 2 Week 4

Question 1

What is learning?

Answer 1

acquisition of new knowledge or skills

Question 2

What is memory?

Answer 2

retention of learned information

Question 3

What are the two broad categories of memory?

Answer 3

Declarative (explicit)
-memory of facts and events
Nondeclarative (implicit)
-memory for skills, habits and others that don’t have a conscious component

Question 4

Describe the flow of sensory information into long-term memory

Answer 4

sensory experience, memory acquisition, short-term memory, memory consolidation, long-term memory

Question 5

Where is memory stored in neural circuits?

Answer 5

Distributed Memory Storage: a neural network model
-unique pattern or ratio of neuronal activity
-distributed memory
-no single neuron represents specific memory

Question 6

What is the cellular basis of memory?

Answer 6

modification of synaptic strengths that change the input-output relations of neurons within neural circuits

Question 7

Where do memories reside?

Answer 7

in synaptic modification

Question 8

What is synaptic pasticity?

Answer 8

describe changes in the strengths of synaptic connections in response to experience and neuronal activity

Question 9

What is synaptic strengthening?

Answer 9

-synaptic potentiation
-formation of new synapses

Question 10

What is synaptic weakening?

Answer 10

-synaptic depression
-elimination of exiting synapses

Question 11

What is the Hippocampus?

Answer 11

a brain region that is important for memory formation

Question 12

What is LTP?

Answer 12

Long Term Potentiation
A long-lasting increase of the effectiveness of synaptic transmission
Shown by increased EPSP amplitude

Question 13

What is Hebb’s rule?

Answer 13

synaptic potentiation results when presynaptic activity correlated with strong activation of the postsynaptic neuron

Question 14

What does NMDA receptor activation depend on?

Answer 14

both glutamate and voltage
-Mg2+ blocks the channel at certain negative Vm, even if glutamate binds
-Need depolarization and glutamate for activation and let in lots of Ca2+

Question 15

What does the NMDA receptor act as?

Answer 15

coincidence detector
-Ca2+ entry through NMDA receptor specifically signals presynaptic and postsynaptic neurons are active at the same time

Question 16

What are the mechanisms of LTP in CA1?

Answer 16

Ca2+ through NMDA receptors activate protein kinases (CaMKII)
Achieve LTP by:
1. increasing the effectiveness of existing AMPA receptors on the membrane via phosphorylation of CaMKII
2. inserting new AMPA receptors into the membrane

Question 17

What is the BCM theory?

Answer 17

An extension of Hebb’s rule…
Synaptic depression results when presynaptic activity is correlated with a weak depolarization of a postsynaptic neuron

Question 18

What is LTD?

Answer 18

Long-Term Despression

Question 19

What is the mechanism of LTD in CA1?

Answer 19

-increase protein phosphatase activity
-de-phosophorylate AMPA receptors on the membrane
-remove existing AMPA receptors

Question 20

What is the difference between LTD and LTP?

Answer 20

opposite change of AMPA receptors

Question 21

What accounts for bidirectional synaptic changes?

Answer 21

When the postsynaptic cell is weakly depolarized by other inputs: active synapses undergo LTP instead of LTP

Question 22

Bidirectional plasticity is governed by two simple rules. What are they?

Answer 22

Synapses during strong depolarization of postsynaptic neuron causes LTP (Hebb’s rule)
Synapses during weak depolarization of postsynaptic neuron causes LTD (BCM theory)

Question 23

Describe memory consolidation

Answer 23

Phosphorylation insufficient as long-term memory consolidation mechanism
-phosphorylation of a protein is not permanent
-memories would be erased
Protein molecules themselves are not permanent

Question 24

Describe the regulation of CaMKII

Answer 24

-once activated, autophosphorylation will keep kinases stay “on” permanently
-which may hold LTP and memory for a long time

Question 25

Describe how protein synthesis relations to memory consolidation

Answer 25

-new protein synthesis required during the period of memory consolidation and for formation of long-term memory

Question 26

What is CREB? Why is it relevant?

Answer 26

cyclic AMP response element binding protein (a transcription factor) -bind to cAMP response elements (CREs) to regulate expression of specific genes, which ultimately leads to new protein synthesis

Question 27

Describe the regulation of gene expression by CREB

Answer 27

CREB-2: a repressor of gene expression CREB-1: an activator of gene expression

Question 28

What is synaptic remodeling?

Answer 28

formation of new synapses during learning or memory and demolition of old synapses during learning and memory

Question 29

What are Channelrehodopsins (ChRs):

Answer 29

- a subfamily of light-gated cation channels -they serve as sensory photoreceptors in unicellular green algae, controlled phototaxis

Question 30

What is Halordopsin?

Answer 30

-a yellow-light-activated Cl- pump, found in archaea -to move chloride ions into the cell, reducing the membrane potential

Question 31

What can optogenetics be used for?

Answer 31

to control neural activity with light positive ions = neuron activation negative ions = neuron inhibition

Question 32

What happens to the brain during sleep?

Answer 32

the brain is "disconnected" from both input and output ends

Question 33

What is the Electroencephalogram (EEG)?

Answer 33

-measurement of generalized activity of cerebral cortex -helps diagnose neurological conditions, such as epilepsy and sleep disorders, and for research

Question 34

How are large EEG signals activated?

Answer 34

synchronous acitivy

Question 35

What are the three functional brain states in humans?

Answer 35

awake REM sleep (rapid eye movement) Non-REM sleep (slow-wave)

Question 36

What type of sleep is known as paradoxical sleep? Why?

Answer 36

REM sleep, EEG of REM sleep is very similar to EEG of an awake state

Question 37

What is happening during non-REM sleep?

Answer 37

an idling brain with moveable body, also called slow-wave sleep

Question 38

What is happening during REM sleeo?

Answer 38

an active, hallucinating brain with a paralyzed body, where dreams occur

Question 39

What are the Sleep promoting neurons?

Answer 39

acetylcholine in the midbrain/pons

Question 40

What do GABAergic neurons in the preoptic area (POA) promote?

Answer 40

sleep

Question 41

What activates GABAergic POA neurons?

Answer 41

ChR2

Question 42

What do neuropeptide hypocretin (Hcrt) and Hcrt neurons promote?

Answer 42

wakefulness

Question 43

What causes narcolepsy?

Answer 43

mutations of Hcrt

Question 44

What are the sleep-promoting factors?

Answer 44

Adenosine: released by neurons; may have inhibitory effects of diffuse modulatory systems Nitric Acid (NO): triggers release of adenosine Muramyl Dipeptide: isolated from the CSF of sleep-deprived goats, facilitates non-REM sleep Interleukin-1 (cytokine): synthesized in brain, stimulates immune system, induces fatigue and sleepiness Melatonin: released at night, inhibited during daylight; helps initiate and maintain sleep- used to treat symptoms of jet lag and insomnia

Question 45

What is the broad behavioral definition of sleep?

Answer 45

Sleep is readily reversible quiescence state that is associated with reduced responsiveness to the environment and under homeostatic control

Question 46

Why do we sleep?

Answer 46

Restoration -sleep to rest and recover and prepare for when we wake again - conserve energy, repair and clear metabolic waste in the brain, facilitate memory and synaptic plasticity Adaptation -sleep to keep out of trouble, hide from predators