When the SCN was isolated from neural input by a knife cut that created an island of hypothalamic tissue, the neural activity in the hypothalamic island
A) remained continuous in constant darkness, failing to support the idea that the SCN is the master clock.
B) remained continuous in constant darkness, providing support for the idea that the SCN is the master clock.
C) remained rhythmic in constant darkness, failing to support the idea that the SCN is the master clock.
D) remained rhythmic in constant darkness, providing support for the idea that the SCN is the master clock.

Question

Quizplus · Accepted Answer

The SCN (Suprachiasmatic Nucleus) is considered the master clock for regulating circadian rhythms. When it was isolated but continued to show rhythmic activity in constant darkness, it demonstrated its intrinsic ability to generate circadian rhythms, supporting the idea that the SCN is the master clock.

When the SCN Was Isolated from Neural Input by a Knife