Amygdala - two lima-bean-sized neural clusters in the limbic system; linked to emotion.

Aphasia - impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding).

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, remembering, thinking, and speaking.

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.

Broca’s area - a frontal lobe brain area, usually in the left hemisphere, that helps control language expression by directing the muscle movements involved in speech.

Cerebellum - the hindbrain’s “little brain” at the rear of the brainstem; its functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

Cerebral cortex - the intricate fabric of interconnected neural cells covering the forebrain’s cerebral hemispheres; the body’s ultimate control and information-processing center.

Cognitive neuroscience - the interdisciplinary study of the brain activity linked with cognition.

Consciousness - our subject awareness of ourselves and our environment.

Corpus callosum - the large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

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 brain’s structure.

Dual processing - the principle that information is often simultaneously processed on separate conscious and unconscious tracks.

Electroencephalogram (EEG) - 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.

fMRI - a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure.

Frontal loves - 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).

Glial cells - Cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory.

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.

*Lesion tissue destruction - any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma.

Limbic system - neural system located mostly in the forebrain - below the cerebral hemispheres - that includes the amygdala, hypothalamus, hippocampus, thalamus, and pituitary gland; associated with emotions and drives.

Medulla - the hindbrain structure that is the brainstem’s base, and controls heartbeat and breathing.

Motor cortex - a cerebral cortex area at the rear of the frontal lobes that controls voluntary movements.

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.

Neurogenesis - the formation of new neurons.

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.

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.

PET (position emission tomography) scan - a technique for detecting brain activity that displays where a radioactive form of glucose goes while the brain performs a given task.

Plasticity - our enormous capacity to learn and adapt

Reticular formation - a nerve network that travels through the brainstem into the thalamus; it filters information and plays an important role in controlling arousal.

*Sensory cortex - a region of the cerebral cortex that is responsible for receiving and interpreting sensory information from various parts of the body.

Split brain - A condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

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.

Thalamus - the forebrain’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.

Wernicke’s area - A brain area, usually in the left temporal lobe, involved in language comprehension and expression.