2.
What will be a hamster's activity pattern if its SCN are completely ablated and it is kept under LD
12:12 conditions? (A) activity remains entrained to LD cycle, (B) activity becomes arrhythmic, (C)
activity free-runs, (D) all activity stops. (1 point)
3.
What will be the otherwise intact hamster's activity pattern if its SCN are completely ablated but
then it receives a transplant of fetal SCN in its brain and is kept under LD 12:12 conditions? (A)
activity entrains to the LD cycle, (B) activity becomes arrhythmic, (C) activity free-runs with the
period of the recipient, (D) activity free-runs with the period of the donor, (E) all activity stops.
(1 point)
4.
SCN transplant experiments using the tau mutant hamsters are viewed as convincing evidence
that the SCN is, indeed, the master oscillator in mammals. What makes this evidence so
convincing? (A) It shows that the transplanted SCN establishes neural connections with the
recipient's brain. (B) It eliminates the possibility that a dormant circadian oscillator is activated
when the SCN is transplanted to the recipient. (C) It shows that the transplanted SCN can
entrain to light/dark cycles presented to the transplant recipient. (D) It shows that neural
connections from the SCN to the rest of the brain are not necessary for rhythmicity.
(1 point)
