Ablate  -  To ablate an area means to purposely disable it, usually by applying some toxic chemical or by surgically removing it. Ablating areas of the brain in animals, although it may sound cruel, helps us to better understand what those areas do.

Amnesia  -  Loss of memory for any biological reason, usually due to damage to the hippocampus, is called amnesia.

Amygdala  -  The amygdala is a structure in the temporal lobe that is involved in processing emotion, especially in the fear response.

Anterior  -  Anterior is a directional term meaning toward the front of the brain. Anterior is the opposite of posterior.

Anterograde Amnesia  -  Anterograde amnesia is the condition of being unable to form or recall new memories since the event that caused the amnesia.

Association Cortex  -  Association cortices located in the frontal, parietal, and temporal areas of the brain store long-term memories and help us draw connections in our knowledge and our experiences.

Autonomic Division  -  The autonomic division of the peripheral nervous system includes nerves that connect the brain and spinal cord to smooth muscles (like the stomach), cardiac muscles, and glands. The autonomic system includes the sympathetic and the parasympathetic divisions.

Brainstem  -  The brainstem, located just above the spinal cord, includes three structures: the midbrain, medulla, and pons. The brainstem controls basic functions such as balance, breathing, and heart rate, as well as basic behaviors such as eating and copulating.

Broca's Aphasia  -  Broca's aphasia, caused by damage to Broca's area, is characterized by the inability to produce grammatical language. People with Broca's aphasia also have difficulty understanding sentences with complex grammar.

Broca's Area  -  Broca's area, located in the left frontal lobe near the primary motor cortex, is responsible for producing speech that follows the rules of grammar and for understanding complex grammatical structures.

Caudal  -  Caudal is a directional term meaning toward the front of the brain along the longitudinal axis of the forebrain. The opposite of caudal is rostral.

Central Nervous System  -  The central nervous system is an all-inclusive name for the brain and the spinal cord.

Central Sulcus  -  The central sulcus is a large inward fold in the brain tissue running from the top to the middle of the brain. It marks the division between the frontal and parietal lobes.

Cerebral Cortex  -  The cerebral cortex of the brain includes all four lobes: frontal, temporal, parietal, and occipital. The cortex carries out high- level functions such as attention, language, and memory, as well as mediating some bodily sensations and movements.

Circadian Rhythms  -  Circadian rhythms describe the patterns of physiological changes that accompany cycles of sleep and wakefulness.

Computerized Tomography  -  Researchers use CT scans to create an image of the brain. CT scans are useful for revealing damaged or abnormal areas in the brain.

Coronal  -  A coronal slice of the brain cuts the brain from side to side, so that we see the brain as though we were looking at it from the front.

Diencephalon  -  The diencephalon is a subcortical structure that is made up of the thalamus and the hypothalamus.

Dorsal  -  Dorsal is a directional term meaning above either the longitudinal axis of the brainstem and spinal cord or the longitudinal axis of the forebrain.

Electroencephalograph (EEG)  -  EEG technology measures electrical activity in local areas of the brain. Because neurons use electricity to communicate, EEG gives a decent measurement of levels of overall activity in particular areas of the brain.

Fissure  -  Fissures are very deep sulci.

Forebrain  -  The forebrain is a term referring inclusively to all areas of the brain except the spinal cord and brainstem.

Frontal Lobe  -  The frontal lobe is the most anterior area of the brain, located anterior to the central sulcus and superior to the lateral fissure. It controls many high-level functions, including planning, inhibition, and memory encoding. The primary motor cortex and prefrontal cortex are located in the frontal lobe.

Functional Magnetic Resonance Imaging (fMRI)  -  Researchers use functional magnetic resonance imaging to take three-dimensional pictures of the brain at work. By studying the blood flow in the brain while a subject performs a particular task, researchers can discover which areas of the brain are being used.

Gage, Phineas  -  Phineas Gage was a nineteenth-century construction worker whose frontal lobe was destroyed in an accident, leaving the rest of his brain intact. His case has been widely studied to try to discover the functions of the frontal lobe.

Gyrus  -  Gyri are outward folds in the surface of the brain's tissue.

Hebb's Rule  -  Hebb's rule, "Cells that fire together, wire together," succinctly states the governing principle of long-term potentiation. If two neurons are repeatedly activated at the same time, the connection between them will be strengthened so that they can activate each other in the future.

Hemisphere  -  The cortex of the brain is divided into a right and a left hemisphere which appear to be mirror images of each other. The two hemispheres are almost entirely separate, connected only by a thick bundle of nerves called the corpus collosum.

Hippocampus  -  The hippocampus, located in the temporal lobe, is responsible for the formation of new memories.

H.M.  -  H.M. is a famous neuropsychological patient. As a result of selective brain damage to his hippocampus, H.M. lost his short-term memory while retaining his long-term memory. This dichotomy is important to our understanding of how memories are formed and stored selectively in the brain, and so H.M.'s case has been studied widely by many neuropsychologists.

Horizontal  -  A horizontal slice of the brain cuts it from front to back, so that we see the brain as though we were looking down at it.

Hormone  -  Hormones are chemicals in the bloodstream that act on various organs to adjust the body's vital physiological systems.

Hypothalamus  -  The hypothalamus, part of the diencephalon, is responsible for hormone secretion in the body.

Inferior  -  Inferior is a directional term meaning toward the bottom of the brain. Inferior is the opposite of superior.

Inhibition  -  Inhibition is the ability to suppress one's initial reaction or inclination in favor of the correct choice. Inhibition is thought to be mediated by the frontal lobes.

Korsakoff's Syndrome  -  Korsakoff's syndrome causes memory loss and often afflicts alcoholics.

Lateral Fissure  -  The lateral fissure is a deep fold in the brain that runs horizontally between the frontal and temporal lobes.

Lateral Zone  -  The lateral zone of the hypothalamus is organized differently than the other two zones and can be thought of as part of another nearby structure, the midbrain reticular formation, rather than the hypothalamus.

Lobe  -  The cerebral cortex is divided into four sections, called lobes, along the lines of several major fissures and sulci. The four lobes are: frontal, temporal, parietal, and occipital. Because there are two hemispheres in the brain, there are actually two of each lobe, a right and a left.

Long-Term Potentiation (LTP)  -  Long-term potentiation strengthens connections between neurons based on their patterns of activity, according to Hebb's rule.

Magnetic Resonance Imaging (MRI)  -  Researchers use magnetic resonance imaging to take three-dimensional pictures of the brain at rest. By measuring water density, it can detect injured areas of the brain in a noninvasive way (no need to pry open the skull or even inject patients with anything).

Medial Zone  -  The medial zone of the hypothalamus drives instinctual behaviors (e.g. feeding, reproduction, and parenting) and regulates internal states (e.g. temperature and water balance).

Medulla  -  The medulla is the most inferior of three structures in the brainstem. It works together with the pons to control postural and vital reflexes.

Midbrain  -  The midbrain is the most superior of three structures in the brainstem. It governs basic behaviors like eating and walking, and it works together with the pons to regulate levels of sleep and arousal.

Motor Neuron  -  Motor neurons carry signals from the brain and spinal cord to the muscles and glands of the body.

Occipital Lobe  -  The occipital lobe, located in the most posterior section of the brain, deals mostly with visual information. The primary visual cortex is part of the occipital lobe.

Organic Brain Damage  -  Organic brain damage is any injury caused by some natural event, such as a stroke or an accident.

Parasympathetic System  -  The parasympathetic division of the autonomic system controls bodily functions that promote growth, energy conservation, and regeneration.

Parietal Lobe  -  The primary function of the parietal lobe is to mediate attention. It also contains the somatic sensory cortex and some association cortex.

Parieto-Occipital Sulcus  -  This sulcus separates the parietal and occipital lobes, running in an inferior and anterior direction from the surface of the brain.

Peripheral Nervous System  -  The peripheral nervous system includes sensory neurons and motor neurons. The components of the PNS dealing with motor neurons can be divided into the autonomic and the somatic systems.

Periventricular Zone  -  The periventricular zone of the hypothalamus controls hormone secretion.

Perseverate  -  To perseverate means to keep giving a response that was formerly correct but is now incorrect. Perseveration during the Wisconsin Card Sort task is a sign of frontal lobe damage.

Plastic  -  An area of the brain is said to be plastic if it is able to change in response to input from the environment.

Pons  -  The pons is the middle structure of three structures in the brainstem. It works with the medulla to organize postural and vital reflexes, and with the midbrain to control levels of sleep and arousal.

Positron Emission Tomography (PET)  -  PET is a method used to research which areas of the brain are active during a certain task. Radioactive dye is injected into the cranial bloodstream and then tracked. The most active areas show the highest levels of radioactivity.

Postcentral Gyrus  -  The postcentral gyrus is the fold of brain tissue located just posterior to the central sulcus. The somatic sensory cortex is located on the postcentral gyrus.

Posterior  -  Posterior is a directional term meaning toward the back of the brain. Posterior is the opposite of anterior.

Postural Reflexes  -  Postural reflexes, controlled by the medulla and the pons, mediate balance during stasis and movement.

Precentral Gyrus  -  The precentral gyrus is the fold of brain tissue located just anterior to the central sulcus. The primary motor cortex is located on the precentral gyrus.

Prefrontal Cortex  -  The prefrontal cortex, the most anterior part of the frontal lobe, is involved in inhibition and other functions of the frontal lobe. It is the most recently developed part of the brain.

Primary Auditory Cortex  -  The primary auditory cortex, located in the temporal lobe on the edge of the lateral fissure, analyzes sound input from receptors in the ear.

Primary Motor Cortex  -  The primary motor cortex controls directed movements of the body through nerves that travel though the brainstem and spinal cord to the muscles of the body.

Primary Visual Cortex  -  The primary visual cortex, located in the occipital lobe, receives signals from the retina (part of the eye) and analyzes visual information to help form a coherent picture of the world we see.

Retrograde Amnesia  -  Retrograde amnesia is the condition of not being able to recall memories formed before the event that caused the amnesia.

Rostral  -  Rostral is a directional term meaning toward the back of the brain along the longitudinal axis of the forebrain. The opposite of rostral is caudal.

Sagittal  -  A saggital section cuts the brain vertically from front to back, so that we see the brain as if we were looking at it from the side.

Secondary Motor Cortex  -  The secondary motor cortex, located in the frontal lobe, helps us plan our movements before the primary motor cortex actually sends the commanding signals to the body.

Sensory Areas  -  The term sensory areas encompasses the regions of the cortex that receive input from the senses, primarily the visual cortex, the somatic sensory cortex, and the auditory cortex.

Sensory Neuron  -  Sensory neurons carry input from sensory receptors all over the body to the brain and spinal cord.

Somatic Division  -  The somatic division of the peripheral nervous system includes the nerves that connect the brain and spinal cord to skeletal muscles (like biceps).

Somatic Sensory Cortex  -  The somatic sensory cortex, located just posterior to the central sulcus in the parietal lobe, receives input from receptors in the body. It mediates our sense of touch.

Spinal Cord  -  The spinal cord contains motor and sensory nerves that carry information between the brain and the body.

Stroke  -  A stroke is a medical affliction, like a heart attack of the brain. When a section of the brain is temporarily deprived of oxygen, usually due to a blocked blood vessel, neurons die quickly, causing damage to the deprived area.

Subcortical  -  Located in the subcortex, the portion of the brain immediately below the cerebral cortex.

Sulcus  -  Sulci are inward folds in the surface of the brain's tissue.

Superior  -  Superior is a directional term meaning toward the top of the brain. Superior is the opposite of inferior.

Sympathetic System  -  The sympathetic division of the autonomic system controls bodily functions that mediate the "fight or flight" response to stress.

Temporal Lobe  -  The temporal lobe, located inferior to the lateral fissure, contains the hippocampus and the amygdala, two very important structures, in addition to the primary auditory area, Wernicke's area, and a section of association cortex.

Thalamus  -  The thalamus is a subcortical structure, part of the diencephalon, that acts as a relay center for signals being sent to, from, or within the brain.

Tract  -  A tract is a bundle of nerves that are located close to one other and which generally serve a similar purpose.

Ventral  -  Ventral is a directional term meaning below either the longitudinal axis of the brainstem and spinal cord or the longitudinal axis of the forebrain. Ventral is the opposite of dorsal.

Vital Reflexes  -  Vital reflexes, controlled by the medulla and the pons, mediate the internal functions that keep us alive, such as breathing and heart rate.

Wernicke's Aphasia  -  Wernicke's aphasia, caused by damage to Wernicke's area, is a condition characterized by the inability to understand spoken language. People with Wernicke's aphasia often have trouble producing appropriate content words as well, although their grammar is still fairly good.

Wernicke's Area  -  Wernicke's area lies in the left temporal lobe, adjacent to the primary auditory area. Wernicke's area helps us understand spoken language. People with damage to this area suffer from Wernicke's aphasia.

Wisconsin Card Sort (WCS)  -  In the Wisconsin Card Sort task, subjects are required to sort a number of cards by a rule that changes periodically. Poor performance on the WCS can indicate problems with frontal lobe function.