Neuroscience & Neurobiology
The stable, negative charge of a neuron when it is inactive, typically around -70 mV.
Resting potential
Substances that increase neural activity and arouse the nervous system.
Stimulants
A condition characterized by compulsive engagement in rewarding stimuli, despite adverse consequences, often involving changes in brain chemistry and function.
Addiction
The two halves of the brain (left and right), each specializing in different functions.
Hemispheres
A sleep stage where dreaming usually happens, brain activity becomes more active, and eyes move rapidly under closed eyelids; body muscles are relaxed.
REM Sleep
The process by which neurotransmitters are reabsorbed by the neuron that released them, terminating their action.
Reuptake
Substances that decrease neural activity and slow down the nervous system.
Depressants
A phenomenon where increasing amounts of a substance are required to achieve the same effect due to the body's adaptation.
Tolerance
The part of the brain connecting the cerebrum with the spinal cord, responsible for basic life functions such as heartbeat and breathing.
Brainstem
The stages of sleep without rapid eye movements, characterized by slower brain waves and physical rest; includes stages 1, 2, and 3.
NREM Sleep
A substance that blocks the reabsorption of neurotransmitters, increasing their availability in the synaptic cleft.
Reuptake inhibitor
Substances that produce hallucinations or alter perception.
Hallucinogens
Symptoms that occur when a person stops or reduces intake of a substance they are dependent on.
Withdrawal
The part of the brain involved in reasoning.
Frontal Lobe
Stage 1 Sleep
The lightest stage of sleep where you drift in and out of sleep; brain activity slows, and you may experience sudden muscle contractions (hypnic jerks).
A neurotransmitter that decreases the likelihood of a neuron firing an action potential.
Inhibitory neurotransmitter
Narcotic substances that relieve pain and can induce euphoria.
Opioids
An autoimmune disease where the immune system attacks the protective covering of nerve fibers, leading to communication problems between the brain and the rest of the body.
Multiple Sclerosis
A brain structure that relays sensory and motor signals to the cerebral cortex.
Thalamus
Stage 2 Sleep
A deeper sleep than Stage 1; characterized by sleep spindles (bursts of brain activity) and a slowing heart rate and body temperature.
A neurotransmitter that increases the likelihood of a neuron firing an action potential.
Excitatory neurotransmitter
Substances that affect the brain and alter consciousness, mood, or perception.
Psychoactive drugs
A chronic autoimmune disorder that causes weakness in the skeletal muscles by disrupting the communication between nerves and muscles.
Myasthenia Gravis
A bundle of nerve fibers connecting the two hemispheres of the brain, facilitating communication between them.
Corpus Callosum
Stage 3 Sleep
The deepest stage of NREM sleep, also called slow-wave sleep; very restorative and hard to wake from, with delta brain waves dominating.