Construct: Circadian Rhythms
Circadian Rhythms are endogenous self-sustaining oscillations that organize the timing of biological systems to optimize physiology and behavior, and health. Circadian Rhythms:
- Are synchronized by recurring environmental cues;
- Anticipate the external environment;
- Allow effective response to challenges and opportunities in the physical and social environment;
- Modulate homeostasis within the brain and other (central/peripheral) systems, tissues and organs;
- Are evident across levels of organization including molecules, cells, circuits, systems, organisms, and social systems.
Input5HT Dopamine GABA Glutamate Melanopsin NPY PACAP Substance P
SCN Synchronizing and Modulating AgentsAVP Calbindin cAMP cGMP NO Steroid hormones VIP
OutputAVP Cortisol GABA Melatonin VIP
InputRaphe to SCN projection Retinal cells Retino-hypothalamic tract Retinogeniculate tract
OutputBasolateral amygdala/ Hippocampus Central extended amygdala (central nucleus of the amygdala / Bed nucleus of the stria terminalis) HPA axis Hypothalamic neuroendocrine cell groups Hypothalamic orexin projections PVN, DMH, subparaventricular zone, PVT SCN/PVN/SCG/pineal Sympathetic / parasympathetic nervous system
Intrinsic to SCNSuprachiasmatic nucleus (SCN) core/shell
Genetic Approaches – genome-wide association study, candidate gene, epigenomics, circadian genomics (temporal gene expression), mutagenesis, gene targeting, quantitative trait loci.