BRAIN BEE

acetylcholine

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

action potential

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 neg. to pos.

addiction

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

adenosine

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

adrenal gland

endocrine organ that secretes hormones. outer layer (adrenal cortex) secretes stress hormone cortisol. inner portion (adrenal medulla) secretes epinephrine and norepinephrine in concert w/ activation of sympathetic nervous system in fight or flight.

alzheimer's disease (AD)

major cause of dementia in elderly. neurogenerative disorder characterized by death of neurons in hippocampus, cerebral cortex, and other brain regions. earliest symptoms include forgetfulness; disorientation as to time or place; and difficulty with concentration, calculation, language, and judgment. in final states, individuals may be bedridden.

amnesia

memory impairment usually caused by brain damage or disease, or by drugs such as some anesthetics. can be retrograde (forget past events) or anterograde (cannot form new memories) or both.

amygdala

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

amytrophic lateral sclerosis (ALS)

lou gehrig's disease, causes motor neurons in brain and spinal cord to disintegrate, resulting in loss of control of voluntary muscle movements (ex. walking)

analgesic

drug that relieves pain without causing a loss of consciousness

anxiety

state of heightened arousal characterized by intense worry

aphasia

disturbance in language comprehension (werenicke's) or production (broca's), 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

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

astrocyte

star-shaped glial cell in CNS that nourishes neurons; regulates formation, maintenance, and pruning of synapses; contributes to blood-brain barrier

attention

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

attention deficit hyperactivity disorder (ADHD)

condition characterized by excessively inattentive, hyperactive, or impulsive behaviors

auditory nerve

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

autism spectrum disorder (ASD)

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

autonomic nervous system

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

axon

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

axon terminal

ends of axons where neurotransmitters are released to target cells

basal ganglia

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

benzodiazepines

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

blood-brain barrier

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

brain waves

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

brain-derived neurotrophic factor (BDNF)

neurotrophic peptide that supports growth and survival of neurons

epinephrine

hormone released by adrenal medulla and specialized sites in brain. also known as adrenaline, quickly released into bloodstream during times of stress. puts body into general state of arousal (helps cope with challenge).

episodic memory

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

estrogen

female sex hormone produced primarily in the ovaries.

excitation

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

excitatory

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. executive function comprises impulse control, working memory, and mental flexibility.

forebrain

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

fovea

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

fragile x syndrome

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

frontal lobe

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

functional magnetic resonance imaging (fMRI)

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

gamma-aminobutyric acid (GABA)

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

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

glutamate

amino acid neurotransmitter that acts to excite neurons. stimulates NMDA and AMPA.

gray matter

portions of brain that are gray in color because they are composed mainly of neural cell bodies. includes cerebral cortex as well as subcortical structures.

growth cone

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

hair cells

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

hindbrain

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

hippocampus

seahorse-shaped structure located within the brain and considered an important part of the limbic system. involved in learning, memory, and emotion.

histamine

compound with multiple functions in body. in brain -- neurotransmitter to stimulate arousal. local inflammatory responses in body trigger release of histamines from immune cells.

homeostasis

normal equilibrium of body function.

hormones

chemical messengers secreted by endocrine glands to regulate activity of target cells. play a role in sexual development, calcium and bone metabolism, growth, etc.

huntington's disease

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

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

hypothalamus

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

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

inhibitory

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

insomnia

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

interneuron

neuron that exclusively signals another neuron.

involuntary movement

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

group of structures deep within the brain involved in motivation and emotion. hippocampus, amygdala, thalamus, and hypothalamus.

long-term memory

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

long-term potentiation (LTP)

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

magnetic resonance imaging (MRI)

technique that uses magnetic fields to create high-quality, 3D images of organs and structures in the body. noninvasive and does not expose body to any type of radiation.

magnetoencephalography (MEG)

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

medulla

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

melatonin

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

membrane potential

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

mentalization

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

microglia

glial cells in CNS that function as resident immune cells.

midbrain

anterior segment of brainstem. with pons and medulla, involved in many functions (regulation of heart rate, respiration, pain perception, and movement)

migration

process by which 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 adenosine triphosphate (ATP).

mood

general state of mind and emotional disposition.

motor cortex

specialized region in cortex involved in the planning and execution of movement.

motor neuron

neuron that carries information from CNS to muscles.

motor unit

functional unit made up of an alpha motor neuron and all of the muscle fibers into contains and controls (a few to a hundred or more).

myelin

compact fatty material that surrounds and insulates axons of some neurons and accelerates transmission of electrical signals.

narcolepsy

sleep disorder resulting from loss of orexin neurons in hypothalamus that causes pronounced sleepiness during day.

nerve growth factor (NGF)

substance whose role is to guide neuronal growth during embryonic development, especially in peripheral nervous system. also probably helps to sustain neurons in adults.

neurodegeneration

progressive destruction and loss of neurons. alzheimer's, parkinson's and ALS are examples of neurodegenerative diseases.

neurogenesis

production and growth of new nerve cells during development and in certain brain regions, throughout life.

neuromodulator

chemical messenger that alters strength of a synapse by modifying the production and/or response to neurotransmitters. neurotransmitters, hormones, and immune molecules can all function as neuromodulators.

neuron

nerve cell specialized for the transmission of information and characterized by long, fibrous projections called axons and shorter, branchlike projections called dendrites.

neurotransmitters

chemical messengers released by neurons at a synapse for the purpose of relaying information to other cells.

neurotransmitter receptors

proteins embedded in postsynaptic cell membrane that bind neurotransmitters to alter cell's excitability.

nociceptors

nerve endings that signal sensation of pain.

nodes of ranvier

unmyelinated gaps in an axon's myelin sheath along which electrical impulses travel.

nondeclarative memory

implicit or procedural memory, type of long-term memory that is stored and retrieved without conscious effort.

norepinephrine

catecholamine neurotransmitter produced both in the brain and in the peripheral nervous system. involved in arousal and sleep regulation, mood, and blood pressure.

nucleus accumbens

region at base of forebrain that is part of the basal ganglia and is important in motivation and reward.

obsessive-compulsive disorder

anxiety disorder characterized by uncontrollable, recurring thoughts (obsessions) and repetitive behaviors (compulsions) that attempt to mitigate the obsessions.

occipital lobes

one of four subdivisions of cerebral cortex. plays a role in processing visual information.

olfactory bulbs

round, knoblike structures of brain responsible for processing the sense of smell. specialized olfactory receptor cells are located in a small patch of mucous membrane lining roof of nose. axons of these sensory cells pass through perforations in the overlying bone and enter two elongated olfactory bulbs lying on top of the bone.

oligodendrocyte

glial cell in CNS that forms myelin.

opioids

substances that bind to opioid receptors in brain to relieve pain. endorphins are a type of endogenous opioid produced in brain. natural and synthetic opioids, such as morphine and codeine, can be prescribed to treat pain.

optic chiasm

place in brain where optic nerves meet and some axons cross over the opposite hemisphere in animals with binocular vision.

orexin

hormone produced in hypothalamus that stimulates arousal.

oxytocin

hormone produced in hypothalamus and released by pituitary gland that initiates release of milk from mammary glands and stimulates uterine contractions. involved in love and social bonding.

pain

unpleasant sensory and emotional experience often signaling tissue damage, or the potential for tissue damage.

paralysis

loss of muscle function in all or part of the body, usually due to nerve damage.