Sleep And Reward

Question 1

Study by aschoff

Answer 1

Free running rhythm- Circadian rhythm’s confused due to absence of external cues

Question 2

Role of suprachiasmatic nucleus

Answer 2

Circadian rhythms in using neurons in response to light. Photosensitive Retinal ganglion cells respond to light and send signals to the cells to the scn via the retinohypothalamic tract

Question 3

What are slave oscillators

Answer 3

Determine sleeping and eating behaviours

Question 4

Effect of scn damage in biorhythms

Answer 4

Doesn’t affect eating abs sleeping but occur at wrong times

Question 5

What is sleep

Answer 5

Reversible state of decreased responsiveness to stimuli

Question 6

Where are slave oscillators entrained

Answer 6

Hypothalamus
Thalamus
Pituitary gland
Pineal gland

Question 7

Stages of sleep

Answer 7

Non REM
N1- theta 4-7
N2 theta 11-16 and K complexes with sleep spindles
N3 - delta 1-4
REM - beta 15-30

Question 8

Function of reticular activating system

Answer 8

Cell Nuclei and fibres that run through the Brainstem - Responsible for wakefulness (stimulates activity in the cerebral cortex)

Question 9

What areas of the Brainstem and what neurons are part of the RAS

Answer 9

Locus correlus- noradrenaline
Raphe nucleus - serotonin
Pedunculopontine and dorsal tegmental nuclei (Ach)
Tuberomamillary nucleus - histamine

Question 10

What NTs are monaminergic

Answer 10

Serotonin, dopamine and

Question 11

What areas influence ras but are not part of it

Answer 11

Basal forebrain - alertness but immobile
Median raphe nucleus- movements

Question 12

Characteristics of non REM sleep

Answer 12

Decrease in firing rate of Brainstem modulatory neurons (no movement)
EEG sleep spindles generated by thalamic neurons activity
As nerem progresses spindles dissapear
Slow delta waves replace spindles

Question 13

Characteristics of rem sleep

Answer 13

V1 is active
Frontal lobe cortical areas less active
Limbic system more active
Extrastriate areas more active

Question 14

What drives rem sleep

Answer 14

Pons nuclei:
Peribrachial area
Medial pontine

Question 15

How to determine difference between rem on and off cells

Answer 15

On cells- increase firing rate just before rem sleep

Off cells- increase firing before end of rem sleep

Question 16

How does sleep involve ltp

Answer 16

Synaptic consolidation and strengthening services from co activation of the hippocampus and neocortex

Question 17

Theory for LTM in neocortex

Answer 17

Spindle density is correlated with post sleep information retereival (consolidation).
Coupling of spindles to upper state of oscillation is important to synaptic plasticity and LTM formation

Question 18

What is the sequential hypothesis

Answer 18

REM sleep serves as a function in memory formation prior to non rem sleep

Question 19

Waves in non rem sleep

Answer 19

Slow oscillation
Spindles
Ripples

Question 20

What makes up the basal ganglia

Answer 20

Caudate nucleus
Putamen
Globes pallidus
Substansia nigra
Sun thalamic nucleus

Question 21

Function of basal ganglia

Answer 21

Part of extrapyramidal motor system- Motor control and motor learning (some functions in executive function and emotions)

Question 22

What makes up the striatum and function

Answer 22

Caudate n
N accumbens
Putamen
Movement and reward and conjunction of both

Question 23

What neurons make up the basal ganglia

Answer 23

Medium spiny gabaergic
Some interneurons and astroglia

Question 24

What is the function of the direct pathway

Answer 24

Facilaite movement

Question 25

What is function of indirect pathway

Answer 25

Inhibit movement so only one action is coordinated

Question 26

Mechanism of direct pathway

Answer 26

1.Cortex wants to start movement
2.Sends glu excitatory projections to striatum
(GABA inhibitory pathway from internal 3. Segment to thalamus inhibits excitation of frontal cortex)
4. Striatum sends signals to internal segment to inhibit inhibition
= motor cortex activated

Question 27

Mechanism of indirect pathway

Answer 27

Cortex sends projections to input nuclei (striatum)
Sends inhibitory signals to internal segment to inhibit projections from external segment
Increased inhibition from internal segment to thalamus
= no motor cortex innervation

Question 28

Role of external segment

Answer 28

Influence processing of motor information of the internal segment

Question 29

How does Dopamine play a role in motor control

Answer 29

Dopamine I’m vta projects to nucleus accumbens forming the direct and indirect pathways
Da projections from Snc inhibit indirect pathway and excite direct pathway
- medium spiny neurons in direct have D-1r (Gs excitatory)
- m.spiny neurons in indirect have D2-r (Gi-coupled inhibitory)

Question 30

What is main area for reward

Answer 30

Vta

Question 31

What areas are involved in reward seeking behaviour

Answer 31

Medial forebrain (receives da projection)
Vta - realease da

Question 32

Role of Vta in reward

Answer 32

Code for magnitude and value
Increased da activity if first given small reward and then larger reward
Increase activity for punishment

Question 33

How does adenosine impact reward

Answer 33

M.spiny neurons release adenosine which goes into glu neurons and stops release of glu from D1 and D2 (early inhibition)

Question 34

How does D2 cause inhibition.

Answer 34

Release endocanaboids that inhibit glu from cortical projections( late inhibition)

Question 35

What is synaptic homeostasis theory

Answer 35

When awake activity in synapses is upscaled in cortical and subcortical areas like hippocampus
When sleeping these are downscaled to baseline levels (synapses return to rest) to conserve energy.
Low electrical waves during sleep return to rest and synapses become more plastic for next waking period

Question 36

Why is energy conservation needed for synapses

Answer 36

Synapses I’m learning are more metabolicly active so take longer to return to rest.
Recently active synapses during nrem sleep undergo changes to allow formation of new memories