Unit 2 Biological Basis of Behavior

Neuroscience

how the body and brain enable emotions, memories, and sensory experiences

Neuron

a specialized cell transmitting nerve impulses; a nerve cell.

sensory neurons

Nerve cells that carry impulses towards the central nervous system

motor neurons

Nerve cells that conduct impulses away from the central nervous system

interneuron

connect motor neurons and sensory neurons

Dendrite

Branchlike parts of a neuron that are specialized to receive information.

Soma

cell body

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

myelin sheath

covers the axon of some neurons and helps speed neural impulses

glial cells

cells in the nervous system that support, nourish, and protect neurons

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

synaptic vesicles

Tiny pouches or sacs in the axon terminals that contain chemicals called neurotransmitters.

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

Reuptake

A process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane.

resting potential

the state of the neuron when not firing a neural impulse

action potential

a neural impulse; a brief electrical charge that travels down an axon

threshold

Level of stimulation needed to trigger a neural impulse

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing.

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

refractory period

the time following an action potential during which a new action potential cannot be initiated

Endorphins

natural, opiate-like neurotransmitters linked to pain control and to pleasure

Dopamine

a neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal

Serotonin

A neurotransmitter that affects hunger,sleep, arousal, and mood.

Acetylcholine

A neurotransmitter that enables learning and memory and also triggers muscle contraction

Norepinephrine

A neurotransmitter involved in arousal, as well as in learning and mood regulation

GABA

An inhibitory neurotransmitter in the brain.

Glutamate

A major excitatory neurotransmitter; involved in memory

Agonist

A chemical that mimics the action of a neurotransmitter.

Antagonist

A chemical that blocks that action of a neurotransmitter

central nervous system

consists of the brain and spinal cord

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

somatic nervous system

Division of the Peripheral Nervous System that controls the body's skeletal muscles.

autonomic nervous system

A subdivision of the peripheral nervous system. Controls involuntary activity of visceral muscles and internal organs and glands.

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations; fight or flight

parasympathetic nervous system

a set of nerves that helps the body return to a normal resting state; rest and digest

reflex arc

A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus, often without conscious brain involvement.

endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

Melatonin

A hormone manufactured by the pineal gland that produces sleepiness.

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Lesioning

A naturally or experimentally caused destruction of brain tissue.

Electroencephalogram (EEG)

record of the electrical activity of the brain

fMRI (functional MRI)

A technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function.

brain stem

Connection to spinal cord. Filters information flow between peripheral nervous system and the rest of the brain.

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

reticular activating system

a nerve network that travels through the brainstem and plays an important role in controlling arousal

Thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Cerebellum

Balance and coordination

limbic system

neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Amygdala

A limbic system structure involved in memory and emotion, particularly fear and aggression.

Hippocampus

a neural center located in the limbic system; helps process explicit memories for storage

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

cerebral cortex

the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

frontal lobes

Conscious, rational thoughts, problem solving

parietal lobes

interpret sensory impulses coming from skin

involved in understanding speech and verbal articulation of thoughts and emotions

aid in interpretation of shapes and textures of objects being touched

occipital lobes

involved in recognition of visual images

temporal lobe

A region of the cerebral cortex responsible for hearing and language.

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

area at the front of the parietal lobes that registers and processes body touch and sensations

aphasia

impairment of language

Broca's aphasia

condition resulting from damage to Broca's area, causing the affected person to be unable to speak fluently, to mispronounce words, and to speak haltingly

Wernicke's aphasia

condition resulting from damage to Wernicke's area, causing the affected person to be unable to understand or produce meaningful language

Plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

monozygotic twins

identical twins

dizygotic twins

fraternal twins

addiction

A physiological or psychological dependence on a drug

circadian rhythm

the biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle

physical dependence

A type of addiction in which the body itself feels a direct need for a drug

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation (created by repeated awakenings during REM sleep)

Tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior

Stimulants

Drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, and Ecstasy) that excite neural activity and speed up body functions.

Depressants

drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions

Hallucinogens

psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input

Opioid

opium or any of the drugs derived from opium, including morphine, heroin, and codeine that provide pain relief and and sense of euphoria

Biopsychologist

a psychologist who studies the relationship between behavior and biological processes, especially activity in the nervous system

Eugenics

study of factors that influence the hereditary qualities of the human race and ways to improve those qualities

twin studies

A research design in which hereditary influence is assessed by comparing the resemblance of identical twins and fraternal twins with respect to a trait.

myasthenia gravis (MG)

chronic disease characterized by muscle weakness and thought to be caused by a defect in the transmission of impulses from nerve to muscle cell

inhibitory neurotransmitters

chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing

substance p

A neurotransmitter that is involved in the transmission of pain messages to the brain.

Ghrelin

A hunger-arousing hormone secreted by an empty stomach

Brain Stem

midbrain, pons, medulla oblongata

nucleus accumbens (brain reward center)

a dopamine-rich area in the forebrain that is critical in the physiology of reward

Oxytocin

a hormone released by the pituitary gland that causes increased contraction of the uterus during labor and stimulates the ejection of milk into the ducts of the breasts.

Leptin

hormone that signals the hypothalamus and brain stem to reduce appetite and increase the amount of energy used

excitatory neurotransmitters

chemicals released from the terminal buttons of a neuron that excite the next neuron into firing

REM Sleep Behavior Disorder

a neurological disorder in which the person does not become paralyzed during REM sleep and thus acts out dreams

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

all-or-none principle

The principle that when a neuron fires, it fires with the same potency each time; a neuron either fires or not—it cannot partially fire, although the frequency of firing can vary.

Multiple Sclerosis (MS)

destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue

Adrenaline

A hormone released into the bloodstream in response to physical or mental stress

Caffeine

a stimulant drug found in coffee, tea, cola drinks, chocolate, and many over-the-counter medications

Cocaine

a powerful and addictive stimulant, producing temporarily increased alertness and euphoria

Alcohol

Depressant

Marijuana

a drug, whose effects include euphoria, impairment of judgment and concentration and occasionally hallucinations

Heroin

narcotic drug derived from opium that is extremely addictive

split brain research

-study of patients with severed corpus callosum

-involves sending messages to only one side of the brain

-demonstrates right and left brain specialization

split brain patients

people whose corpus callosum has been surgically severed