Behavioral Neuroscience - Circadian Rhythms

Flashcards covering key terms and concepts related to circadian rhythms as discussed in behavioral neuroscience.

Circadian rhythms

Functions of a living organism that display a rhythm of about 24 hours, including physical, mental, biochemical, and behavioral changes.

Diurnal

Active during the light, as seen in humans, dogs, and elephants.

Nocturnal

Active during the dark, as in bats and skunks.

Crepuscular

Active during twilight, shortly before sunrise and after sunset, as in house cats and deer.

Endogenous clock

An internal timing mechanism that generates circadian rhythms.

Zeitgeber

A cue, such as light or food, that synchronizes the endogenous biological clock.

Suprachiasmatic nucleus (SCN)

The main biological clock in mammals, regulating circadian rhythms.

ipRGCs (intrinsically photosensitive retinal ganglion cells)

Retinal ganglion cells that contain melanopsin and are sensitive to light, relaying information about light to the SCN.

Melanopsin

A photopigment found in ipRGCs that makes them sensitive to light, especially blue light.

Chronotype

A person's natural preference for sleep and wake times, often classified as morning-type (lark) or evening-type (night owl).

Infradian rhythms

Biological rhythms longer than a day, such as reproductive cycles.

Ultradian rhythms

Biological rhythms shorter than a day, such as bouts of activity and hormone release.

Melatonin

A hormone released by the pineal gland that regulates sleep-wake cycles and is suppressed by light.

Free running

When an animal's biological clock operates without external cues, leading to variations in activity patterns.