Module 12

Question 1

What are the two ways clock outputs can be categorized?

Answer 1

• The message the clock is sending to the rest of the brain

- The medium by which the message is delivered

Question 2

How can neurons deliver messages?

Answer 2

• Synaptic transmission

- Molecule diffusion

Question 3

The message from the SCN clock responsible for daily sleep-wake cycles includes both _____

Answer 3

“go to sleep” and “wake up” signals

Question 4

During the first 12h after a 24h sleep deprivation, intact rats _____

Answer 4

Sleep more than usual

Question 5

Intact rats sleep ____ than arrhythmic rats after 24h sleep deprivation, most likely because _____

Answer 5

• Less

- The SCN sends signals to discourage sleeping during the subjective day

Question 6

During the sleep period, the SCN releases ______

Answer 6

A signal that inhibits locomotor activity

Question 7

What type of signals have priority in the SCN?

Answer 7

Signals that inhibit activity

Question 8

The Opponent Process model was proposed by _____ based on ______

Answer 8

• Edgar and Dement in 1997

- The finding that squirrel monkeys sleep more and become arrhythmic after SCN ablations

Question 9

The Opponent Process model does not work for _____

Answer 9

Rodents

Question 10

Sleep propensity in humans is lowest ______

Answer 10

Late in the daily sleep phase

Question 11

Studies suggest that cutting all SCN axons from the SCN in hamsters causes ______ and in rats causes _____

Answer 11

• No change in activity rhythms

- Loss of rhythms

Question 12

What is likely a signal responsible for SCN-dependant inhibition of activity during the daily rest period?

Answer 12

TGF-alpha