| Term | Definition |
| lesion | tissue destruction. a brain lesion is a naturally or experimentally caused destruction of brain tissue. |
| 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. |
| PET (positron emission tomography) scan | a visual display of brain activity sweeping across the brain's surface. these waves are measured by electrodes placed on the scalp. |
| MRI (magnetic resonance imaging) | a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. These scans show brain anatomy. |
| fMRI (functional MRI) | a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. these scans show brain function and structure. |
| brainstem | the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; it's responsible for automatic survival functions. |
| medulla | the base of the brainstem; controls heartbeat and breathing |
| thalamus | the brains' sensory control 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 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 hemisphere; associated with emotions and drives. |
| hippocampus | a neural center located in the limbic system; helps process explicit memories for storage. |
| amygdala | two lime bean-sized neural clusters in the limbic system; linked to emotion |
| hypothalamus | a neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking body temperature), helps govern the endocrine system via the pituitary gland, and its 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. |
| frontal lobes | portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgement. |
| parietal lobes | portion of the cerebral cortex lying at the top of the head and 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; included areas that receives information from the visual fields. |
| temporal lobes | portion of the cerebral cortex lying roughly above the ears; includes the auditory ares, each receiving the 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. |
| associating 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. |
| 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 brains hemispheres and carrying messages between them. |
| 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. |
