biological psychology
the scientific study of the links between biological and psychological processes
neuron
a nerve cell; the basic building blocks the nerve system
dendrites
a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
myelin sheath
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next
action potential
a neural impulse; a brief electrical charge that travels down an axon
refractory period
a period of inactivity after a neuron has fired
threshold
the level of stimulation required to trigger a neural impulse
all-or-none response
a neuron's reaction of either firing or not firing
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft
neurotransmitters
chemical messengers that cross the synaptic gap between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
reuptake
a neurotransmitter's reabsorption by the sending neuron
endorphins
morphine within"-- natural, opiate-like neurotransmitters linked to. pain control and to pleasure
agonist
a molecule that, by binding to a receptor site, stimulates a response
antagonist
a molecule that, by binding to a receptor site, inhibits or blocks a response
nervous system
the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
central nervous system
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
nerves
bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs
sensory neurons
neurons that carry incoming information from the sensory receptors to the brain and spinal cord
motor neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
interneurons
neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs
somatic nervous system
the division the peripheral nervous system that controls the body's skeletal muscles
autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs
sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy
reflex
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
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
adrenal glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress
pituitary gland
the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
lesion
tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue
electroencephalogram
an amplified recording of the waves of electrical activity sweeping across the brain's surface. These waves are measured by electrodes placed on the scalp
CT scan
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure
PET scan
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
MRI
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.
fMRI
a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as its structure.
brainstem
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions
medulla
the base of the brainstem; controls heartbeat and breathing
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
reticular formation
a nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal
cerebellum
the "little brain" at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory
limbic system
neural system located below the cerebral hemispheres; associated with emotions and drives
amygdala
two lima-bean-sized neural clusters in the limbic system; linked to emotion
hypothalamus
a neural structure lying below the thalamus; it directs several maintenance activities, helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward
cerebral cortex
the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center
glial cells
cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning and thinking
frontal lobes
portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgements
parietal lobes
portion of the cerebral cortex lying at the top of the head toward the rear; receives sensory input for touch and body position
occipital lobes
portion of the cerebral cortex lying at the back of the head; includes areas that receive information from visual fields
temporal lobes
portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear
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 movement sensations
association areas
areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, thinking, and speaking
plasticity
the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience
neurogenesis
the formation of new neurons
corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
split brain
a condition resulting from surgery tat isolates the brain's two hemispheres by cutting the fibers connecting them
consciousness
our awareness of ourselves and our environment
cognitive neuroscience
the interdisciplinary study of the brain activity linked with cognition
dual processing
the principle that information is often simultaneously processed on separate conscious and unconscious tracks
behavior genetics
the study of the relative power and limits of genetic and environmental influences on behavior
environment
every external influence, from prenatal nutrition to the people and things around us
chromosomes
threadlike structures made of DNA molecules that contain the genes
DNA
a complex molecule containing the genetic information that makes up the chromosomes
genes
the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins
genome
the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes
identical twins
twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms
fraternal twins
twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment
molecular genetics
the subfield of biology that studies the molecular structure and function of genes
heritability
the proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied
interaction
the interplay that occurs when the effect of one factor depends on another factor
epigenetics
the study of environmental influences on gene expression that occur without DNA change
evolutionary psychology
the study of evolution of behavior and the mind, using principles of natural selection
natural selection
the principle that, among the range of inherited trait variations, those contributing to reproduction and survival will be most likely to be passed on to succeeding generations
mutation
a random error in gene replication that leads to a change