near-death experience
an altered state of consciousness reported after a close brush with death (such as cardiac arrest); often similar to drug-induced hallucinations.
biological psychology
the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes.
Some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.
biopsychosocial approach
an integrated approach that incorporates biological, psychological, and social-cultural levels of analysis.
levels of analysis
the differing complementary views, from biological to psychological to social-cultural, for analyzing any given phenomenon.
neuroplasticity
the brainâs ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
lesion
tissue destruction. Brain lesions may occur naturally (from disease or trauma), during surgery, or experimentally (using electrodes to destroy brain cells).
EEG (electroencephalogram)
an amplified recording of the waves of electrical activity sweeping across the brainâs surface. These waves are measured by electrodes placed on the scalp.
MEG (magnetoencephalography)
a brain-imaging technique that measures magnetic fields from the brainâs natural electrical activity.
CT (computed tomography) scan
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brainâs structure.
PET (positron emission tomography)
a technique for detecting brain activity that displays where a radioactive form of glucose goes while the brain performs a given task.
MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.
fMRI (functional MRI)
a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure.
hindbrain
consists of the medulla, pons, and cerebellum; directs essential survival functions, such as breathing, sleeping, and wakefulness, as well as coordination and balance.
midbrain
found atop the brainstem; connects the hindbrain with the forebrain, controls some motor movement, and transmits auditory and visual information.
forebrain
consists of the cerebral cortex, thalamus, and hypothalamus; manages complex cognitive activities, sensory and associative functions, and voluntary motor activities.
brainstem
the 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 hindbrain structure that is the brainstemâs base; controls heartbeat and breathing.
thalamus
the forebrainâs 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 into the thalamus; it filters information and plays an important role in controlling arousal.
cerebellum
the hindbrainâs âlittle brainâ at the rear of the brainstem; its functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.
limbic system
neural system located mostly in the forebrain â below the cerebral hemispheres â that includes the amygdala, hypothalamus, hippocampus, thalamus, and pituitary gland; associated with emotions and drives.
amygdala
two lima-beanâsized neural clusters in the limbic system; linked to emotion.
hypothalamus
a limbic system neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system, and is linked to emotion and reward.
hippocampus
a neural center in the limbic system that helps process explicit (conscious) memories â of facts and events â for storage.
cerebral cortex
the intricate fabric of interconnected neural cells covering the forebrainâs cerebral hemispheres; the bodyâs ultimate control and information-processing center.
frontal lobes
the portion of the cerebral cortex lying just behind the forehead. They enable linguistic processing, muscle movements, higher- order thinking, and executive functioning (such as making plans and judgments).
parietal lobes
the portion of the cerebral cortex lying at the top of the head and toward the rear; it receives sensory input for touch and body position.
occipital lobes
the portion of the cerebral cortex lying at the back of the head; it includes areas that receive information from the visual fields.
temporal lobes
the portion of the cerebral cortex lying roughly above the ears; it includes the auditory areas, each of which receives information primarily from the opposite ear. They also enable language processing.
motor cortex
a cerebral cortex area at the rear of the frontal lobes that controls voluntary movements.
somatosensory cortex
a cerebral 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, but rather are involved in higher mental functions such as learning, remembering, thinking, and speaking.
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 that separates the brainâs two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.
consciousness
our subjective awareness of ourselves and our environment.
cognitive neuroscience
the interdisciplinary study of the brain activity linked with cognition (thinking, knowing, remembering, and communicating).
dual processing
the principle that information is often simultaneously processed on separate conscious and unconscious tracks.
blindsight
a condition in which a person can respond to a visual stimulus without consciously experiencing it.
parallel processing
processing multiple aspects of a stimulus or problem simultaneously.
sequential processing
processing one aspect of a stimulus or problem at a time; generally used to process new information or to solve difficult problems.
sleep
a periodic, natural loss of consciousness â as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation. (Adapted from Dement, 1999.)
circadian rhythm
our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.
REM sleep
rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active (Sometimes called R sleep.)
alpha waves
the relatively slow brain waves of a relaxed, awake state.
NREM sleep
non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.
hallucinations
false sensory experiences, such as seeing something in the absence of an external visual stimulus.
hypnagogic sensations
bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep. (Also called hypnic sensations.)
delta waves
the large, slow brain waves associated with deep sleep.
suprachiasmatic nucleus (SCN)
a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN adjusts melatonin production, thus modifying our feelings of sleepiness.
insomnia
recurring problems in falling or staying asleep.
narcolepsy
a sleep disorder characterized by uncontrollable sleep attacks. The affected person may lapse directly into REM sleep, often at inopportune times.
sleep apnea
a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.