Chronobiology Lexicon

A
Adenosine

The metabolic byproduct that builds up in the brain during the day, creating the biological pressure to sleep.

Alpha-Santalol

A major organic compound found in sandalwood, known for its ability to cross the blood-brain barrier and induce sedation.

Amacrine Cells

Interneurons in the retina that help process signals from photoreceptors to ganglion cells, playing a role in spectral sensitivity.

Amplitude (Circadian)

The strength of the circadian rhythm, measured by the difference between the peak and trough of biological markers like temperature.

B
Bisglycinate

A chelated form of magnesium bound to glycine, optimized for absorption and neurological downregulation.

Blue Light

High-energy visible light (450-495nm) that triggers ipRGCs to inhibit melatonin production.

C
Chronobiology

The field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar- and lunar-related rhythms.

Cortisol Awakening Response (CAR)

The sharp rise in cortisol levels immediately upon waking that sets the timing for the evening sleep pressure onset.

Crypthochromes

A class of flavoproteins found in the retina that are sensitive to blue light and involved in the circadian clock mechanism.

G
GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter that reduces neuronal excitability, essential for transitioning into deep sleep.

Glymphatic System

The macroscopic waste clearance system for the central nervous system, most active during the deepest phases of sleep.

H
Hypothalamus

The region of the forebrain that coordinates both the autonomic nervous system and the activity of the pituitary gland, housing the master clock.

I
ipRGCs

Intrinsically photosensitive Retinal Ganglion Cells; the sensors in the eye responsible for detecting blue light and signaling the SCN.

L
Linalool

A naturally occurring terpene found in lavender used to modulate GABA receptors and induce relaxation.

Lumen

A measure of the total quantity of visible light emitted by a source per unit of time.

M
Melanopsin

The photopigment within ipRGCs that is specifically sensitive to short-wavelength blue light.

Melatonin

The indoleamine hormone produced by the pineal gland that signals the bodys transition into the nocturnal phase.

Monochromatic

Light consisting of a single, narrow wavelength band, used in the protocol to prevent circadian disruption.

N
Nanometer (nm)

A unit of length equal to one-billionth of a meter, used to measure light wavelengths.

P
Parasympathetic Nervous System

The rest and digest branch of the autonomic nervous system, activated through the protocol.

Pineal Gland

A small endocrine gland in the brain responsible for the synthesis and secretion of melatonin.

Photoperiod

The period of time during each day that an organism receives illumination.

S
Suprachiasmatic Nucleus (SCN)

The master biological clock of the body, located in the hypothalamus above the optic chiasm.

Spectral Power Distribution (SPD)

A map of the radiant power emitted by a light source at each wavelength in the visible spectrum.

V
Vagus Nerve

The tenth cranial nerve, which serves as the primary conduit for parasympathetic signals to the heart, lungs, and digestive tract.

Z
Zeitgeber

Any external or environmental cue that entrains or synchronizes an organisms biological rhythms to the earths 24-hour cycle.