Chapter 4 (Psychology)

hypothalamus

A brain structure involved in emotions and drives vital to survival, such as fear, hunger, thirst, and reproduction; it regulates the autonomic nervous system.

amygdala

A brain structure involved in the arousal and regulation of emotion and the initial emotional response to sensory information.

hippocampus

A brain structure involved in the storage of new information in memory.

cerebellum

A brain structure that regulates movement and balance and is involved in some cognitive tasks.

thalamus

A brain structure that relays sensory messages to the cerebral cortex.

synaptic vesicles

A brief change in electrical voltage that occurs between the inside and the outside of an axon when a neuron is stimulated; it serves to produce an electrical impulse

nerves

A bundle of nerve fibers (axons and sometimes dendrites) in the peripheral nervous system.

neuron

A cell that conducts electrochemical signals; the basic unit of the nervous system; also called a nerve cell.

neurotransmitter

A chemical substance that is released by a transmitting neuron at the synapse and that alters the activity of a receiving neuron.

spinal cord

A collection of neurons and supportive tissue running from the base of the brain down the center of the back, protected by a column of bones (the spinal column).

cerebral cortex

A collection of several thin layers of cells covering the cerebrum; it is largely responsible for higher mental functions. Cortex is Latin for "bark" or "rind."

reticular activating system (RAS)

A dense network of neurons found in the core of the brain stem; it arouses the cortex and screens incoming information.

myelin sheath

A fatty insulation that may surround the axon of a neuron; prevents signals in adjacent cells from interfering with each other.

limbic system

A group of brain areas involved in emotional reactions and motivated behavior.

vasopressin

A hormone that contributes to relationships in both sexes by promoting attachment and trust.

melatonin

A hormone, secreted by the pineal gland, that is involved in the regulation of daily biological rhythms.

oxytocin

A hormone, secreted by the pituitary gland, that stimulates uterine contractions during childbirth, facilitates the ejection of milk during nursing, and seems to promote, in both sexes, attachment and trust in relationships.

PET scan (positron-emission tomography)

A method for analyzing biochemical activity in the brain, using injections of a glucoselike substance containing a radioactive element.

MRI (magnetic resonance imaging)

A method for studying body and brain tissue, using magnetic fields and special radio receivers; functional MRI (fMRI) is a faster form often used in psychological research.

transcranial magnetic stimulation (TMS)

A method of stimulating brain cells, using a powerful magnetic field produced by a wire coil placed on a person's head; it can be used by researchers to temporarily inactivate neural circuits and is also being used therapeutically.

lesion method

A method which involves damaging or removing sections of brain in animals and then observing the effects.

dendrites

A neuron's branches that receive information from other neurons and transmit it toward the cell body. "little tree"

axon

A neuron's extending fiber that conducts impulses away from the cell body and transmits them to other neurons or to muscle or gland cells."axle"

neuroethics

A new interdisciplinary specialty, neuroethics, has been formed to address the many legal, ethical, and scientific questions raised by brain research, including those raised by the development of neuroenhancing drugs.

split-brain surgery

A procedure in which the bundle of fibers that connects the cerebral hemispheres (the corpus callosum) is cut to reduce the severity of epileptic seizures.

electroencephalogram (EEG)

A recording of neural activity detected by electrodes.

pituitary gland

A small endocrine gland at the base of the brain that releases many hormones and regulates other endocrine glands.

pons

A structure in the brain stem involved in, among other things, sleeping, waking, and dreaming.

medulla

A structure in the brain stem responsible for certain automatic functions, such as breathing and heart rate.

peripheral nervous system

All portions of the nervous system outside the brain and spinal cord; it includes sensory and motor nerves. Handles the central nervous system's input and output.

Wernicke's are

An area of the left temporal lobe known that is involved in language comprehension.

functional MRI (fMRI)

An ultrafast version of the MRI that can capture brain changes many times a second as a person performs a task, such as reading a sentence or solving a puzzle.

spinal reflexes

Behaviors that are automatic, requiring no conscious effort.

axon terminals

Branches at the end of the axon

motor nerves

Carry orders from the central nervous system to muscles, glands, and internal organs. They enable us to move, and they cause glands to contract and to secrete substances, including chemical messengers called hormones.

glia

Cells that support, nurture, and insulate neurons, remove debris when neurons die, enhance the formation and maintenance of neural connections, and modify neuronal functioning.

endorphins

Chemical substances in the nervous system that are similar in structure and action to opiates; they are involved in pain reduction, pleasure, and memory and are known technically as endogenous opioid peptides.

hormones

Chemical substances, secreted by organs called glands, that affect the functioning of other organs.

nodes

Constrictions in the myelin sheath that divide it into segments which make it look a little like a string of sausage links.

electrode

Devices that detect the electrical activity of millions of neurons in particular regions of the brain and are widely used in research and medical diagnosis.

adrenal hormones

Hormones that are produced by the adrenal glands and that are involved in emotion and stress.

sex hormones (androgens, estrogens, progesterone)

Hormones that regulate the development and functioning of reproductive organs and that stimulate the development of male and female sexual characteristics; they include androgens, estrogens, and progesterone.

visual field

If you look straight ahead at the visual field in front of you, everything in the left side of the scene goes to the right half of your brain, and everything in the right side of the scene goes to the left half of your brain.

stem cells

Immature cells that renew themselves and have the potential to develop into mature cells; given encouraging environments, stem cells from early embryos can develop into any cell type.

sensory nerves

In the PNS, they carry messages from teh special receptors in the skin, muscles, and other internal and external sense organs to the spinal cord, which sends them along to the brain. These nerves put us in touch with both the outside world and the activities of out own bodies.

motor cortex

In the frontal lobes, they issue orders to the 600 muscles of the body the produce voluntary movement.

Broca's area

In the left frontal lobe, this region handles speech production.

visual cortex

In the occipital lobes, this is where visual signals are processed.

somatosensory cortex

In the parietal lobes, they receives information about pressure, pain, touch, and temperature from all over the body.

auditory cortex

In the temporal lobes, they process sounds.

endocrine glands

Internal organs that produce hormones and release them into the bloodstream.

frontal lobes

Lobes at the front of the brain's cerebral cortex; they contain areas involved in short-term memory, higher-order thinking, initiative, social judgment, and (in the left lobe, typically) speech production.

occipital lobes

Lobes at the lower back part of the brain's cerebral cortex; they contain areas that receive visual information.

temporal lobes

Lobes at the sides of the brain's cerebral cortex; they contain areas involved in hearing, memory, perception, emotion, and (in the left lobe, typically) language comprehension.

parietal lobes

Lobes at the top of the brain's cerebral cortex; they contain areas that receive information on pressure, pain, touch, and temperature.

receptor sites

Neurotransmitter molecules bind briefly with this: special molecules in the membrane of the receiving neuron's dendrites, fitting these sites much as a key fits a lock.

epinephrine and norepinephrine

Produced by the inner part of the adrenal glands.

cortisol

Produced by the outer part of each adrenal gland, it increases blood-sugar levels and boosts energy.

synaptic cleft

Separates the neurons by a minuscule space.

localization of function

Specialization of particular brain areas for particular functions.

lateralization

Specialization of the two cerebral hemispheres for particular operations.

plasticity

The brain's ability to change and adapt in response to experience, by reorganizing or growing new neural connections.

corpus callosum

The bundle of nerve fibers connecting the two cerebral hemispheres.

cerebrum

The largest brain structure, consisting of the upper part of the brain; divided into two hemispheres, it is in charge of most sensory, motor, and cognitive processes. From the Latin for "brain."

prefrontal cortex

The most forward part of the frontal lobes. It is the most recently evolved part of our brains, and is associated with such complex abilities as reasoning, decision making, and planning.

brain stem

The part of the brain at the top of the spinal cord, consisting of the medulla and the pons.

cell body

The part of the neuron that keeps it alive and determines whether it will fire—transmit a message to other neurons—depending on inputs from other neurons.

central nervous system

The portion of the nervous system consisting of the brain and spinal cord.

neurogenesis

The production of new neurons from immature stem cells.

(hemispheric) dominance

The results confirm that nearly all right-handed people and a majority of left-handers process language mainly in the left hemisphere. The left side is also more active during some logical, symbolic, and sequential tasks, such as solving math problems and understanding technical material.They believe that the left hemisphere usually exerts control over the right hemisphere.

synapse

The site where transmission of a nerve impulse from one nerve cell to another occurs; it includes the axon terminal, the synaptic cleft, and receptor sites in the membrane of the receiving cell.

olfactory bulb

The smell center in the brain

sympathetic nervous system

The subdivision of the autonomic nervous system that mobilizes bodily resources and increases the output of energy during emotion and stress.

parasympathetic nervous system

The subdivision of the autonomic nervous system that operates during relaxed states and that conserves energy

somatic nervous system

The subdivision of the peripheral nervous system that connects to sensory receptors and to skeletal muscles; sometimes called the skeletal nervous system.

autonomic nervous system

The subdivision of the peripheral nervous system that regulates the internal organs and glands.

cerebral hemispheres

The two halves of the cerebrum.

association cortex

These "silent" areas that are involved in higher mental processes.

action potential

Tiny sacs in the tip of the axon terminal, that open and release a few thousand molecules of a chemical substance called neurotransmitter.