Brain Bee

Acetylcholine

A critical neurotransmitter that controls functions such as memory, attention, sleep, heart rate, and muscular activity.

Action Potential

An electrical charge that travels along the axon to the neuron's terminal, where it triggers the release of a neurotransmitter. This occurs when a neuron is activated and temporarily reverses the electrical state of its interior membrane from negative to positive.

Addiction

Loss of control over drug intake or compulsive seeking and taking of drugs, despite adverse consequences.

Adenosine

A neurochemical that inhibits wakefulness, serving the purpose of slowing down cellular activity and diminishing arousal. Levels decrease during sleep.

Adrenal Gland

An endocrine organ that secretes hormones. The outer layer (adrenal cortex) secretes the stress hormone cortisol. The inner portion (adrenal medulla) secretes epinephrine and norepinephrine in concert with the activation of the sympathetic nervous system in the "fight or flight" response.

Alzheimer's Disease (AD)

A major cause of dementia in the elderly, this neurodegenerative disorder is characterized by the death of neurons in the hippocampus, cerebral cortex, and other brain regions. The earliest symptoms of the disease include forgetfulness; disorientation as to time or place; and difficulty with concentration, calculation, language, and judgment. In the final stages, individuals are incapable of self-care and may be bedridden.

Amnesia

A memory impairment usually caused by brain damage or disease, or by drugs such as some anesthetics. People with itmay be unable to recall events from the past, form new memories, or both.

Amygdala

A structure in the forebrain that is an important component of the limbic system and plays a central role in emotional learning, particularly within the context of fear.

Amyotrophic Lateral Sclerosis (ALS)

Commonly known as Lou Gehrig's disease, causes motor neurons in the brain and spinal cord to disintegrate, resulting in loss of control of voluntary muscle movements such as walking.

Analgesic

A drug that relieves pain without causing a loss of consciousness.

Anxiety

A state of heightened arousal characterized by intense worry.

Aphasia

Disturbance in language comprehension or production, often as a result of a stroke.

Apoptosis

Programmed cell death induced by specialized biochemical pathways, often serving a specific purpose in the development of an animal.

Arousal

A physiological state involving changes in the body and brain that motivate behavior and enable response to stimuli.

Astrocyte

A star-shaped glial cell in the central nervous system that nourishes neurons; regulates the formation, maintenance, and pruning of synapses; and contributes to the blood-brain barrier.

Attention

A state of arousal in which the brain's sensory processing is directed at a limited number of stimuli. Voluntary (endogenous) is a conscious decision to focus on a particular stimulus. Involuntary (exogenous) is an unplanned focus on a change in the environment, such as a loud noise or sudden movement.

Attention Deficit Hyperactivity Disorder (ADHD)

A condition characterized by excessively inattentive, hyperactive, or impulsive behaviors.

Auditory Nerve

A branch of the vestibulocochlear nerve that transmits auditory information from the cochlea of the ear to the brain.

Autism Spectrum Disorder (ASD)

A set of conditions characterized, in part, by impaired social communication and interaction, and narrow, obsessive interests or repetitive behaviors.

Autonomic Nervous System

A part of the peripheral nervous system responsible for regulating the activity of internal organs. It includes the sympathetic and parasympathetic nervous systems.

Axon

The fiber-like extension of a neuron by which it sends information to target cells.

Axon Terminal

The ends of axons where neurotransmitters are released to target cells.

Basal Ganglia

A group of interconnected structures located deep in the brain that play an important role in voluntary movement, motor skill learning, and habits. These structures include the caudate nucleus, putamen, nucleus accumbens, globus pallidus, and substantia nigra.

Benzodiazepines

A class of drugs that enhance activity of the brain's primary inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), to produce sedative and anti-anxiety effects and are often prescribed to treat anxiety disorders and insomnia.

Blood Brain Barrier

A protective membrane composed of tightly packed endothelial cells lining the brain's capillaries and highly specialized astrocytes, which controls the passage of certain molecules into and out of the brain.

Brain Derived Neurotrophic Factor (BDNF)

A neurotrophic peptide that supports the growth and survival of neurons.

Brain Waves

Oscillating patterns of brain activity that can be detected and recorded using electroencephalography (EEG).

Brainstem

The major route by which the forebrain sends information to and receives information from the spinal cord and peripheral nerves. It includes the midbrain, pons, and medulla, and it controls, among other things, respiration and the regulation of heart rhythms.

Broca's Area

A region of the frontal lobe — usually the left hemisphere — that governs speech production.

Cell Body

Also called the soma, the part of a neuron that contains the nucleus (with DNA) and the organelles, but not the projections such as the axon or dendrites.

Central Nervous System

The brain and spinal cord.

Cerebellum

A large structure located at the roof of the hindbrain that helps to control the coordination of movement by making connections to the pons, medulla, spinal cord, and thalamus. It also may be involved in aspects of motor learning.

Cerebral Cortex

The wrinkled, outermost layer of the cerebrum consisting primarily of neuron cell bodies.

Cerebrum

The largest part of the human brain associated with higher order functioning, such as thinking, perceiving, planning, and understanding language, as well as the control of voluntary behavior.

Circadian Rhythms

A cycle of behavior or physiological change lasting approximately 24 hours.

Cochlea

A snail-shaped, fluid-filled organ of the inner ear responsible for converting sound into electrical potentials to produce an auditory sensation.

Cognitive Behavioral Therapy

A form of counseling used to identify and change negative thought patterns that can contribute to anxiety and mood disorders.

Computational Neuroscience

A field of neuroscience research that uses computer programs and algorithms to analyze information about the brain, and develops mathematical models to explain brain function.

Cones

A primary receptor cell for vision located in the retina. It is sensitive to color and is used primarily for daytime vision.

Corpus Callosum

The large bundle of nerve fibers linking the left and right cerebral hemispheres.

Cortisol

A hormone manufactured by the adrenal cortex. In humans, it is secreted in the greatest quantities before dawn, readying the body for the activities of the coming day.

Cranial Nerves

Twelve pairs of nerves that can be seen on the bottom surface of the brain. Some of these nerves transmit sensory information; some control the movement of face, head, and neck muscles; others transmit information to internal organs to regulate functions such as blood pressure and heart rate.

Critical Period

A period of heightened plasticity in brain development when certain experiences and sensory inputs are required for the formation of functional brain circuits.

Declarative Memory

Also called explicit memory, a type of memory that can be consciously retrieved. It includes memory of facts (semantic memory) and memory of personal experiences (episodic memory).

Default Mode Network

A collection of brain regions activated during quiet rest.

Dementia

A decline in cognitive ability that interferes with day-to-day functioning.

Dendrite

A treelike extension of the neuron cell body. The primary site for receiving and integrating information from other neurons.

Depolarization

A change in a neuron's membrane potential in which the cytoplasm becomes more positively charged. Neurons must do beyond a certain threshold to generate an action potential.

Depression

A psychiatric disorder characterized by sadness, hopelessness, pessimism, loss of interest in life, reduced emotional wellbeing, and abnormalities in sleep, appetite, and energy level.

Dopamine

A catecholamine neurotransmitter present in three circuits of the brain: one that regulates movement; a second, thought to be important for cognition and emotion; and a third that regulates the endocrine system. Deficits of it in the motor circuit are associated with Parkinson's disease. Abnormaities in the second circuit have been implicated in schizophrenia.

Down Syndrome

A condition that results from the presence of an extra copy of chromosome 21. This genetic anomaly is associated with physical and developmental characteristics, including mild to moderate intellectual disabilities; low muscle tone; and an increased risk of congenital heart defects, respiratory problems, and digestive tract obstruction.

Dyslexia

A pronounced difficulty with reading despite normal intelligence, education, and motivation.

Electroencephalography (EEG)

A technology used to record electrical activity of the human brain in response to a variety of stimuli and activities.

Endorphins

Neurotransmitters produced in the brain that generate cellular and behavioral effects like those of morphine.

Epilepsy

A disorder characterized by repeated seizures, which are caused by abnormal excitation of large groups of neurons in various brain regions. Can be treated with many types of anticonvulsant medications.

Epinephrine

A hormone released by the adrenal medulla and specialized sites in the brain. During times of stress, is quickly released into the bloodstream. It then serves to put the body into a general state of arousal, which enables it to cope with the challenge.

Episodic Memory

A type of declarative memory consisting primarily of memory of personal experiences.

Estrogen

A female sex hormone produced primarily in the ovaries.

Excitation

A change in the electrical state of a neuron that is associated with an enhanced probability of action potentials.

Excitatory

A type of neuron (or neurotransmitter) that excites target neurons and increases the likelihood of their firing an action potential.

Executive Function

Higher-level processing that takes place in the brain's prefrontal cortex. comprises impulse control, working memory, and mental flexibility.

Forebrain

A region of the developing brain that goes on to become the cerebral hemispheres and major parts of the limbic system.

Fovea

A small, pitted area in the center of the retina where visual acuity is highest, due to a high density of cones.

Fragile X Syndrome

A genetic condition resulting from a mutation in the FMR1 gene that causes intellectual disability.

Frontal Lobe

One of the four subdivisions of the cerebral cortex. has a role in controlling movement and in the planning and coordinating of behavior.

Functional Magnetic Resonance Imaging (fMRI)

A technology that uses magnetic fields to detect activity in the brain by monitoring blood flow.

Gamma-Aminobutyric Acid (GABA)

An amino acid neurotransmitter in the brain whose primary function is to inhibit the firing of nerve cells.

Glia

Specialized cells that nourish and support neurons.

Glucocorticoid Hormones

Hormones that produce an array of effects in response to stress. Some of the actions help to mediate the stress response, while other, slower actions counteract the primary response to stress and help to re-establish homeostasis.

Glutamate

An amino acid neurotransmitter that acts to excite neurons. stimulates N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). AMPA receptors have been implicated in activities ranging from learning and memory to development and specification of nerve contacts in developing animals. Stimulation of NMDA receptors may promote beneficial changes, whereas overstimulation may be a cause of nerve cell damage or death in neurological trauma and stroke.

Gray Matter

Portions of the brain that are gray in color because they are composed mainly of neural cell bodies, rather than myelinated nerve fibers, which are white. It includes the cerebral cortex as well as subcortical structures.

Growth Cone

A distinctive structure at the growing end of most axons. It is the site where new material is added to the axon.

Hair Cells

Sensory receptors in the cochlea that convert mechanical vibrations to electrical signals; they in turn excite the 30,000 fibers of the auditory nerve that carry the signals to the brainstem.

Hindbrain

The most posterior part of the brain, comprising the pons, medulla, and cerebellum.

Hippocampus

A seahorse-shaped structure located within the brain and considered an important part of the limbic system. One of the most studied areas of the brain, it is involved in learning, memory, and emotion.

Histamine

A compound with multiple functions in the body. In the brain, it acts as a neurotransmitter to stimulate arousal. Local inflammatory responses in the body trigger the release of histamines from immune cells.

Homeostasis

The normal equilibrium of body function.

Hormones

Chemical messengers secreted by endocrine glands to regulate the activity of target cells. They play a role in sexual development, calcium and bone metabolism, growth, and many other activities.

Huntington's Disease

A genetic disorder characterized by involuntary jerking movements of the limbs, torso, and facial muscles, often accompanied by mood swings, depression, irritability, slurred speech, and clumsiness.

Hyperpolarization

A change in a neuron's membrane potential in which the cytoplasm becomes more negatively charged and therefore less likely to fire an action potential.

Hypothalamus

A complex brain structure composed of many nuclei with various functions, including regulating the activities of internal organs, monitoring information from the autonomic nervous system, controlling the pituitary gland, and regulating sleep and appetite.

Inhibition

A change in the electrical state of a neuron that is associated with a decreased probability of firing an action potential.

Inhibitory

A type of neuron (or neurotransmitter) that prevents a target neuron from firing.

Insomnia

A sleep disorder in which people have trouble falling and/or staying asleep.

Interneuron

A neuron that exclusively signals another neuron.

Involuntary Movement

A movement that occurs without conscious control, such as a reflex.

Ion Channel Proteins

embedded in the cell membrane that allow ions or other small molecules to enter or leave the cell.

Limbic System

A group of structures deep within the brain involved in motivation and emotion. The hippocampus, amygdala, thalamus, and hypothalamus are all a part of it

Long Term Memory

The final phase of memory, in which information storage may last from hours to a lifetime.

Long Term Potentiation (LTP)

A long-lasting increase in synaptic strength resulting from an increased number of neurotransmitter receptors on the post-synaptic neuron.

Magnetic Resonance Imaging (MRI)

A technique that uses magnetic fields to create a high-quality, three-dimensional image of organs and structures inside the body. This technology is noninvasive and does not expose the body to X-rays or other radiation.

Magnetoencephalography (MEG)

A technique that can quantitatively measure the strength of activity in various regions of the brain at millisecond resolution.

Medulla

Also called the medulla oblongata, a structure of the brainstem that controls basic functions like swallowing, breathing, and heart rate.

Melatonin

A hormone produced in the pineal gland that regulates responses to light-dark cycles and induces sleep at night.

Membrane Potential

The voltage difference between the inside and outside of a neuron. The typical value of a neuron at rest is -70mV.

Mentalization

The ability to understand the mental states and thoughts of others and oneself.

Microglia

Glial cells in the central nervous system that function as resident immune cells.

Midbrain

The most anterior segment of the brainstem. With the pons and medulla, is involved in many functions, including regulation of heart rate, respiration, pain perception, and movement.

Migration

The process whereby new neurons find their proper position in the brain.

Mitochondria

Small cylindrical organelles inside cells that provide energy for the cell by converting sugar and oxygen into special energy molecules, called adenosine triphosphate (ATP).