A neuro-behavioral condition characterized by inattention and/or hyperactive or impulsive behavior that interferes with functioning, learning, or development.

Star-shaped cells found in the brain and spinal cord. Astrocytes facilitate neurotransmission, provide nutrients to neurons, maintain neuronal ion balance, and support the blood-brain barrier. Astrocytes also play a role in the repair and scarring process of the brain and spinal cord following traumatic injuries.

The shrinking or wasting away of cells, organs, or tissues that may occur as part of a disease process, trauma, or aging.

One of two types of fat, or adipose, tissue (the other being white adipose tissue, or white fat) found in mammals. The primary function of brown adipose tissue is to generate body heat. In contrast to white adipocytes (fat cells), which contain a single lipid droplet, brown adipocytes contain numerous smaller droplets and a much higher number of mitochondria, which make it brown. Brown fat also contains more capillaries than white fat, since it has a greater need for oxygen than most tissues.

Proteins that preserve cell viability at low temperatures by binding to nucleic acids and, subsequently, controlling gene expression. Cold shock proteins have what is known as a "cold-shock domain," a sequence of amino acids whose expression is associated with cold and is thought to help cells survive in lower than optimal temperatures.

A type of proteolytic enzyme that breaks down collagen. Collagenases are involved in both normal and pathological turnover of connective tissues. Their production is significantly increased at sites of inflammation due to the stimulation of pro-inflammatory cytokines.

Cooling of the body for therapeutic purposes. Cryotherapy can include the use of products such as ice packs on a localized portion of the body, such as a joint or muscle, or whole body exposure to extremely low temperatures in water or air. Cryotherapy has profound effects on many parts and functions of the body, including the brain, immune system, and metabolism, among others.

A broad category of small proteins (~5-20 kDa) that are important in cell signaling. Cytokines are short-lived proteins that are released by cells to regulate the function of other cells. Sources of cytokines include macrophages, B lymphocytes, mast cells, endothelial cells, fibroblasts, and various stromal cells. Types of cytokines include chemokines, interferons, interleukins, lymphokines, and tumor necrosis factor.

A neurotransmitter best known for its role in motor, motivation, and pleasure control. Dopamine also functions as a paracrine (cell-to-cell) hormone in other parts of the body. It is derived from tyrosine and is the precursor to norepinephrine and epinephrine. Some evidence suggests that dopamine may also be involved in pain modulation.

Beneficial stress that can be psychological, physical (e.g. exercise), or biochemical (hormesis) in nature.

An antioxidant produced within cells that enzymatically reduces hydrogen peroxide to water to limit its harmful effects. Glutathione peroxidase's primary role is to protect cells from oxidative damage, a key factor in many diseases.

An antioxidant produced within cells that converts oxidized glutathione to reduced glutathione. Glutathione reductase is essential for protection against oxidative damage. Oxidative damage is a key factor in many diseases.

A family of proteins produced by cells in response to exposure to stressful conditions. Heat shock proteins are expressed in response to heat as well as exposure to cold and UV light, and during wound healing and tissue remodeling. Many heat shock proteins function as chaperones by stabilizing new proteins to ensure correct folding or by helping to refold proteins that were damaged by cell stress. A 30-minute 73ºC sauna session in healthy young adults has been shown to cause a robust and sustained increase in the production of heat shock proteins for up to 48 hours afterward.^[1]

A sustained period of winter dormancy in warm-blooded animals. Hibernation is characterized by prolonged periods of inactivity and low nutrient intake.

Biological responses to low-dose exposures to toxins or other stressors such as exercise, heat, cold, fasting, and xenohormetics. Hormetic responses are generally favorable and elicit a wide array of protective mechanisms. Examples of xenohormetic substances include plant polyphenols – molecules that plants produce in response to stress. Some evidence suggests plant polyphenols may have longevity-conferring effects when consumed in the diet.

A proinflammatory cytokine produced by macrophages. IL-1 beta is an important mediator of the body’s inflammatory response. It is involved in a variety of cellular activities, including cell proliferation, differentiation, and apoptosis.

A pro-inflammatory cytokine that plays an important role as a mediator of fever and the acute-phase response. IL-6 is rapidly induced in the context of infection, autoimmunity, or cancer and is produced by almost all stromal and immune cells. Many central homeostatic processes and immunological processes are influenced by IL-6, including the acute-phase response, glucose metabolism, hematopoiesis, regulation of the neuroendocrine system, hyperthermia, fatigue, and loss of appetite. IL-6 also plays a role as an anti-inflammatory cytokine through inhibition of TNF-alpha and IL-1 and activation of IL-1ra and IL-10.

A proinflammatory cytokine produced by macrophages. MIP-1 alpha induces the body’s inflammatory response and is associated with cell adhesion and migration.

The process by which new mitochondria are made inside cells. Many factors can activate mitochondrial biogenesis including exercise, cold shock, heat shock, fasting, and ketones. Mitochondrial biogenesis is regulated by the transcription factor peroxisome proliferator-activated receptor gamma coactivator 1-alpha, or PGC-1α.

An increase in the size of muscle cells that occurs with exercise and physical activity.

The process of forming new neurons. Neurogenesis is essential during embryonic development, but also continues in certain brain regions throughout human lifespan.

A substance produced in the brain. Norepinephrine acts as a hormone and neurotransmitter and is best known for its role in the body’s “fight or flight” response to stress. Its role as a neurotransmitter has been exploited as a molecular target for a class of drugs known as norepinephrine reuptake inhibitors, which were developed for the purpose of treating disorders ranging from ADHD to narcolepsy and depression. Norepinephrine also plays a role in converting white adipose tissue into brown adipose tissue via an uncoupling protein 1 (UCP-1) mediated mechanism.

The master regulator of mitochondrial biogenesis. PGC-1α is activated in human skeletal muscle in response to endurance exercise. It is strongly induced by cold exposure, linking this environmental stimulus to adaptive thermogenesis. PGC-1a has been implicated as a potential therapy for Parkinson's disease by conferring protective effects on mitochondrial metabolism.

A group of lipid-signaling molecules that have diverse hormone-like effects. Prostaglandins play roles in inflammation, vasoconstriction or vasodilation, aggregation or disaggregation of platelets, calcium movement, cell growth, and thermoregulation. Prostaglandins are produced in many places throughout the human body.

A cold-shock protein that is induced by exposure to low temperatures, such as those that encountered during hibernation. In a cell model of Parkinson's disease, RBM3 provided neuroprotection, suggesting that RBM3 induction may be a suitable strategy for Parkinson's disease therapy.^[1]

The loss of skeletal muscle tissue with age. Sarcopenia is one of the most important causes of functional decline and loss of independence in older adults.

Skeletal muscle stem cells. Satellite cells are typically dormant, but if the muscle is stressed or injured, they play essential roles in the regenerative growth of new muscle fibers. They have chemotactic properties, which means they can migrate from one location within a muscle fiber to another, where they can participate in the process of developing a new muscle fiber.

A class of powerful antioxidant enzymes produced in cells. Superoxide dismutases convert harmful superoxide radicals to harmless molecular oxygen and hydrogen peroxide, providing cellular defense against reactive oxygen species.

The junction between one neuron and another or a gland or muscle cell. Synapses are critical elements in the transmission of nerve signals. Their formation is necessary for the establishment and maintenance of the brain’s neuronal network and the precision of its circuitry.

A physiological process that results in the production of heat. There are two types of thermogenesis: shivering and nonshivering. Shivering thermogenesis, as its name implies, involves shivering to produce heat. During shivering, skeletal muscles undergo repeated, rapid contractions that produce little net movement and instead, produce heat. Nonshivering thermogenesis generates heat in the absence of shivering by unique mechanisms in both skeletal muscle and adipose (fat) tissue depots. These processes involve uncoupling electron transport from ATP synthesis and repetitive, non-productive transport of ions across the adipose cell membrane.

A proinflammatory cytokine. TNF-alpha is produced by a wide range of cells, including macrophages, lymphocytes, glial cells, and others. TNF-alpha signaling inhibits tumorigenesis, prevents viral replication, and induces fever and apoptosis. Dysregulation of the TNF-alpha signaling pathway has been implicated in a variety of disorders including cancer, autoimmune diseases, Alzheimer’s disease, and depression.

Muscle fibers used primarily during aerobic activities requiring low-level force and endurance. Type 1 fibers typically exhibit slow contraction times and high fatigue resistance. Also known as “slow twitch” fibers.

Muscle fibers used primarily during activities requiring high-level force, speed production, and low endurance. Type 2 fibers typically exhibit rapid contraction times and low fatigue resistance. Also known as “fast twitch” fibers.

A protein found in the mitochondria of brown adipose tissue, previously known as thermogenin. UCP1 is expressed only in brown adipose tissue, a specialized tissue which functions to produce heat via non-shivering thermogenesis.