Neuroimaging: Non-invasive methods of visualizing the CENTRAL NERVOUS SYSTEM, especially the brain, by various imaging modalities.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Functional Neuroimaging: Methods for visualizing REGIONAL BLOOD FLOW, metabolic, electrical, or other physiological activities in the CENTRAL NERVOUS SYSTEM using various imaging modalities.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Diagnostic Imaging: Any visual display of structural or functional patterns of organs or tissues for diagnostic evaluation. It includes measuring physiologic and metabolic responses to physical and chemical stimuli, as well as ultramicroscopy.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Neuroradiography: Radiography of the central nervous system.Positron-Emission Tomography: An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Frontal Lobe: The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus.Neurosciences: The scientific disciplines concerned with the embryology, anatomy, physiology, biochemistry, pharmacology, etc., of the nervous system.Diagnostic Techniques, Neurological: Methods and procedures for the diagnosis of diseases of the nervous system, central and peripheral, or demonstration of neurologic function or dysfunction.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Atrophy: Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes.Cerebral Cortex: The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Cognition Disorders: Disturbances in mental processes related to learning, thinking, reasoning, and judgment.Prefrontal Cortex: The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.Temporal Lobe: Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the OCCIPITAL LOBE.Alzheimer Disease: A degenerative disease of the BRAIN characterized by the insidious onset of DEMENTIA. Impairment of MEMORY, judgment, attention span, and problem solving skills are followed by severe APRAXIAS and a global loss of cognitive abilities. The condition primarily occurs after age 60, and is marked pathologically by severe cortical atrophy and the triad of SENILE PLAQUES; NEUROFIBRILLARY TANGLES; and NEUROPIL THREADS. (From Adams et al., Principles of Neurology, 6th ed, pp1049-57)Neuroanatomy: Study of the anatomy of the nervous system as a specialty or discipline.Brain Diseases: Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Nerve Net: A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.Mild Cognitive Impairment: A prodromal phase of cognitive decline that may precede the emergence of ALZHEIMER DISEASE and other dementias. It may include impairment of cognition, such as impairments in language, visuospatial awareness, ATTENTION and MEMORY.Image Interpretation, Computer-Assisted: Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Parietal Lobe: Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.Gyrus Cinguli: One of the convolutions on the medial surface of the CEREBRAL HEMISPHERES. It surrounds the rostral part of the brain and CORPUS CALLOSUM and forms part of the LIMBIC SYSTEM.Electroencephalography: Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Amygdala: Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.Magnetoencephalography: The measurement of magnetic fields over the head generated by electric currents in the brain. As in any electrical conductor, electric fields in the brain are accompanied by orthogonal magnetic fields. The measurement of these fields provides information about the localization of brain activity which is complementary to that provided by ELECTROENCEPHALOGRAPHY. Magnetoencephalography may be used alone or together with electroencephalography, for measurement of spontaneous or evoked activity, and for research or clinical purposes.Tomography, Emission-Computed: Tomography using radioactive emissions from injected RADIONUCLIDES and computer ALGORITHMS to reconstruct an image.Dominance, Cerebral: Dominance of one cerebral hemisphere over the other in cerebral functions.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Behavior: The observable response of a man or animal to a situation.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Diffusion Tensor Imaging: The use of diffusion ANISOTROPY data from diffusion magnetic resonance imaging results to construct images based on the direction of the faster diffusing molecules.Emotions: Those affective states which can be experienced and have arousing and motivational properties.Tomography, Emission-Computed, Single-Photon: A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.Connectome: A comprehensive map of the physical interconnections of an organism's neural networks. This modular organization of neuronal architecture is believed to underlie disease mechanisms and the biological development of the CENTRAL NERVOUS SYSTEM.Reaction Time: The time from the onset of a stimulus until a response is observed.Neuropsychology: A branch of psychology which investigates the correlation between experience or behavior and the basic neurophysiological processes. The term neuropsychology stresses the dominant role of the nervous system. It is a more narrowly defined field than physiological psychology or psychophysiology.Mental Processes: Conceptual functions or thinking in all its forms.Semantics: The relationships between symbols and their meanings.Language: A verbal or nonverbal means of communicating ideas or feelings.Diffusion Magnetic Resonance Imaging: A diagnostic technique that incorporates the measurement of molecular diffusion (such as water or metabolites) for tissue assessment by MRI. The degree of molecular movement can be measured by changes of apparent diffusion coefficient (ADC) with time, as reflected by tissue microstructure. Diffusion MRI has been used to study BRAIN ISCHEMIA and tumor response to treatment.Schizophrenia: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.Mental Recall: The process whereby a representation of past experience is elicited.Aphasia: A cognitive disorder marked by an impaired ability to comprehend or express language in its written or spoken form. This condition is caused by diseases which affect the language areas of the dominant hemisphere. Clinical features are used to classify the various subtypes of this condition. General categories include receptive, expressive, and mixed forms of aphasia.Epilepsy: A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Word Association Tests: Lists of words to which individuals are asked to respond ascertaining the conceptual meaning held by the individual.Psycholinguistics: A discipline concerned with relations between messages and the characteristics of individuals who select and interpret them; it deals directly with the processes of encoding (phonetics) and decoding (psychoacoustics) as they relate states of messages to states of communicators.Nervous System Diseases: Diseases of the central and peripheral nervous system. This includes disorders of the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscle.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Image Enhancement: Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.Occipital Lobe: Posterior portion of the CEREBRAL HEMISPHERES responsible for processing visual sensory information. It is located posterior to the parieto-occipital sulcus and extends to the preoccipital notch.Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Executive Function: A set of cognitive functions that controls complex, goal-directed thought and behavior. Executive function involves multiple domains, such as CONCEPT FORMATION, goal management, cognitive flexibility, INHIBITION control, and WORKING MEMORY. Impaired executive function is seen in a range of disorders, e.g., SCHIZOPHRENIA; and ADHD.Limbic System: A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, (September 2, 1998)).Nerve Fibers, Myelinated: A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.Pattern Recognition, Visual: Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.Imaging, Three-Dimensional: The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.Memory, Short-Term: Remembrance of information for a few seconds to hours.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Recognition (Psychology): The knowledge or perception that someone or something present has been previously encountered.Dementia: An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness.Neurobiology: The study of the structure, growth, activities, and functions of NEURONS and the NERVOUS SYSTEM.Verbal Learning: Learning to respond verbally to a verbal stimulus cue.Neurology: A medical specialty concerned with the study of the structures, functions, and diseases of the nervous system.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Face: The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.Speech: Communication through a system of conventional vocal symbols.Brain Injuries: Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Cerebrum: Derived from TELENCEPHALON, cerebrum is composed of a right and a left hemisphere. Each contains an outer cerebral cortex and a subcortical basal ganglia. The cerebrum includes all parts within the skull except the MEDULLA OBLONGATA, the PONS, and the CEREBELLUM. Cerebral functions include sensorimotor, emotional, and intellectual activities.Frontotemporal Dementia: The most common clinical form of FRONTOTEMPORAL LOBAR DEGENERATION, this dementia presents with personality and behavioral changes often associated with disinhibition, apathy, and lack of insight.Neurologic Examination: Assessment of sensory and motor responses and reflexes that is used to determine impairment of the nervous system.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Jealousy: An irrational reaction compounded of grief, loss of self-esteem, enmity against the rival and self criticism.Autobiography as Topic: The life of a person written by himself or herself. (Harrod's Librarians' Glossary, 7th ed)Subliminal Stimulation: Stimulation at an intensity below that where a differentiated response can be elicited.Theory of Mind: The ability to attribute mental states (e.g., beliefs, desires, feelings, intentions, thoughts, etc.) to self and to others, allowing an individual to understand and infer behavior on the basis of the mental states. Difference or deficit in theory of mind is associated with ASPERGER SYNDROME; AUTISTIC DISORDER; and SCHIZOPHRENIA, etc.Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.Cerebral Small Vessel Diseases: Pathological processes or diseases where cerebral MICROVESSELS show abnormalities. They are often associated with aging, hypertension and risk factors for lacunar infarcts (see LACUNAR INFARCTION); LEUKOARAIOSIS; and CEREBRAL HEMORRHAGE.Atlases as Topic: Collections of illustrative plates, charts, etc., usually with explanatory captions.Headache: The symptom of PAIN in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of HEADACHE DISORDERS.Economics, Behavioral: The combined discipline of psychology and economics that investigates what happens in markets in which some of the agents display human limitations and complications.Cerebellar Diseases: Diseases that affect the structure or function of the cerebellum. Cardinal manifestations of cerebellar dysfunction include dysmetria, GAIT ATAXIA, and MUSCLE HYPOTONIA.Evoked Potentials: Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Psychophysiology: The study of the physiological basis of human and animal behavior.Verbal Behavior: Includes both producing and responding to words, either written or spoken.Individuality: Those psychological characteristics which differentiate individuals from one another.Facial Hemiatrophy: A syndrome characterized by slowly progressive unilateral atrophy of facial subcutaneous fat, muscle tissue, skin, cartilage, and bone. The condition typically progresses over a period of 2-10 years and then stabilizes.Cerebellum: The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.Cognitive Science: The study of the precise nature of different mental tasks and the operations of the brain that enable them to be performed, engaging branches of psychology, computer science, philosophy, and linguistics. (Random House Unabridged Dictionary, 2d ed)Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Persistent Vegetative State: Vegetative state refers to the neurocognitive status of individuals with severe brain damage, in whom physiologic functions (sleep-wake cycles, autonomic control, and breathing) persist, but awareness (including all cognitive function and emotion) is abolished.Brain Diseases, Metabolic, Inborn: Brain disorders resulting from inborn metabolic errors, primarily from enzymatic defects which lead to substrate accumulation, product reduction, or increase in toxic metabolites through alternate pathways. The majority of these conditions are familial, however spontaneous mutation may also occur in utero.Brain Damage, Chronic: A condition characterized by long-standing brain dysfunction or damage, usually of three months duration or longer. Potential etiologies include BRAIN INFARCTION; certain NEURODEGENERATIVE DISORDERS; CRANIOCEREBRAL TRAUMA; ANOXIA, BRAIN; ENCEPHALITIS; certain NEUROTOXICITY SYNDROMES; metabolic disorders (see BRAIN DISEASES, METABOLIC); and other conditions.Reward: An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.Facial Expression: Observable changes of expression in the face in response to emotional stimuli.Data Interpretation, Statistical: Application of statistical procedures to analyze specific observed or assumed facts from a particular study.Task Performance and Analysis: The detailed examination of observable activity or behavior associated with the execution or completion of a required function or unit of work.ReadingAging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Brain Neoplasms: Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.Stroke: A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)Chorea: Involuntary, forcible, rapid, jerky movements that may be subtle or become confluent, markedly altering normal patterns of movement. Hypotonia and pendular reflexes are often associated. Conditions which feature recurrent or persistent episodes of chorea as a primary manifestation of disease are referred to as CHOREATIC DISORDERS. Chorea is also a frequent manifestation of BASAL GANGLIA DISEASES.Memory Disorders: Disturbances in registering an impression, in the retention of an acquired impression, or in the recall of an impression. Memory impairments are associated with DEMENTIA; CRANIOCEREBRAL TRAUMA; ENCEPHALITIS; ALCOHOLISM (see also ALCOHOL AMNESTIC DISORDER); SCHIZOPHRENIA; and other conditions.Cerebral Infarction: The formation of an area of NECROSIS in the CEREBRUM caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).Syndrome: A characteristic symptom complex.Bipolar Disorder: A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.Lie Detection: Ascertaining of deception through detection of emotional disturbance as manifested by changes in physiologic processes usually using a polygraph.Echoencephalography: Use of reflected ultrasound in the diagnosis of intracranial pathologic processes.Consciousness: Sense of awareness of self and of the environment.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Neurocysticercosis: Infection of the brain, spinal cord, or perimeningeal structures with the larval forms of the genus TAENIA (primarily T. solium in humans). Lesions formed by the organism are referred to as cysticerci. The infection may be subacute or chronic, and the severity of symptoms depends on the severity of the host immune response and the location and number of lesions. SEIZURES represent the most common clinical manifestation although focal neurologic deficits may occur. (From Joynt, Clinical Neurology, 1998, Ch27, pp46-50)Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Seizures: Clinical or subclinical disturbances of cortical function due to a sudden, abnormal, excessive, and disorganized discharge of brain cells. Clinical manifestations include abnormal motor, sensory and psychic phenomena. Recurrent seizures are usually referred to as EPILEPSY or "seizure disorder."Consciousness Disorders: Organic mental disorders in which there is impairment of the ability to maintain awareness of self and environment and to respond to environmental stimuli. Dysfunction of the cerebral hemispheres or brain stem RETICULAR FORMATION may result in this condition.Speech Perception: The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).Transcranial Magnetic Stimulation: A technique that involves the use of electrical coils on the head to generate a brief magnetic field which reaches the CEREBRAL CORTEX. It is coupled with ELECTROMYOGRAPHY response detection to assess cortical excitability by the threshold required to induce MOTOR EVOKED POTENTIALS. This method is also used for BRAIN MAPPING, to study NEUROPHYSIOLOGY, and as a substitute for ELECTROCONVULSIVE THERAPY for treating DEPRESSION. Induction of SEIZURES limits its clinical usage.Vocabulary: The sum or the stock of words used by a language, a group, or an individual. (From Webster, 3d ed)Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Craniotomy: Any operation on the cranium or incision into the cranium. (Dorland, 28th ed)Anisotropy: A physical property showing different values in relation to the direction in or along which the measurement is made. The physical property may be with regard to thermal or electric conductivity or light refraction. In crystallography, it describes crystals whose index of refraction varies with the direction of the incident light. It is also called acolotropy and colotropy. The opposite of anisotropy is isotropy wherein the same values characterize the object when measured along axes in all directions.Hallucinations: Subjectively experienced sensations in the absence of an appropriate stimulus, but which are regarded by the individual as real. They may be of organic origin or associated with MENTAL DISORDERS.Neurophysiology: The scientific discipline concerned with the physiology of the nervous system.Space Perception: The awareness of the spatial properties of objects; includes physical space.Visual Cortex: Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.Imagination: A new pattern of perceptual or ideational material derived from past experience.Concept Formation: A cognitive process involving the formation of ideas generalized from the knowledge of qualities, aspects, and relations of objects.Leukoencephalopathies: Any of various diseases affecting the white matter of the central nervous system.Anatomy, Artistic: The study of the structures of organisms for applications in art: drawing, painting, sculpture, illustration, etc.Aphasia, Broca: An aphasia characterized by impairment of expressive LANGUAGE (speech, writing, signs) and relative preservation of receptive language abilities (i.e., comprehension). This condition is caused by lesions of the motor association cortex in the FRONTAL LOBE (BROCA AREA and adjacent cortical and white matter regions).Nervous System Physiological Processes: Biological actions and events that constitute the functions of the NERVOUS SYSTEM.Aphasia, Primary Progressive: A progressive form of dementia characterized by the global loss of language abilities and initial preservation of other cognitive functions. Fluent and nonfluent subtypes have been described. Eventually a pattern of global cognitive dysfunction, similar to ALZHEIMER DISEASE, emerges. Pathologically, there are no Alzheimer or PICK DISEASE like changes, however, spongiform changes of cortical layers II and III are present in the TEMPORAL LOBE and FRONTAL LOBE. (From Brain 1998 Jan;121(Pt 1):115-26)Diffuse Axonal Injury: A relatively common sequela of blunt head injury, characterized by a global disruption of axons throughout the brain. Associated clinical features may include NEUROBEHAVIORAL MANIFESTATIONS; PERSISTENT VEGETATIVE STATE; DEMENTIA; and other disorders.Spectroscopy, Near-Infrared: A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.Brain Diseases, Metabolic: Acquired or inborn metabolic diseases that produce brain dysfunction or damage. These include primary (i.e., disorders intrinsic to the brain) and secondary (i.e., extracranial) metabolic conditions that adversely affect cerebral function.Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Architecture as Topic: The art and science of designing buildings and structures. More generally, it is the design of the total built environment, including town planning, urban design, and landscape architecture.Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Auditory Cortex: The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.Cerebral Hemorrhage: Bleeding into one or both CEREBRAL HEMISPHERES including the BASAL GANGLIA and the CEREBRAL CORTEX. It is often associated with HYPERTENSION and CRANIOCEREBRAL TRAUMA.Fluorodeoxyglucose F18: The compound is given by intravenous injection to do POSITRON-EMISSION TOMOGRAPHY for the assessment of cerebral and myocardial glucose metabolism in various physiological or pathological states including stroke and myocardial ischemia. It is also employed for the detection of malignant tumors including those of the brain, liver, and thyroid gland. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1162)Corpus Callosum: Broad plate of dense myelinated fibers that reciprocally interconnect regions of the cortex in all lobes with corresponding regions of the opposite hemisphere. The corpus callosum is located deep in the longitudinal fissure.Statistics as Topic: The science and art of collecting, summarizing, and analyzing data that are subject to random variation. The term is also applied to the data themselves and to the summarization of the data.Putamen: The largest and most lateral of the BASAL GANGLIA lying between the lateral medullary lamina of the GLOBUS PALLIDUS and the EXTERNAL CAPSULE. It is part of the neostriatum and forms part of the LENTIFORM NUCLEUS along with the GLOBUS PALLIDUS.Malformations of Cortical Development: Abnormalities in the development of the CEREBRAL CORTEX. These include malformations arising from abnormal neuronal and glial CELL PROLIFERATION or APOPTOSIS (Group I); abnormal neuronal migration (Group II); and abnormal establishment of cortical organization (Group III). Many INBORN METABOLIC BRAIN DISORDERS affecting CNS formation are often associated with cortical malformations. They are common causes of EPILEPSY and developmental delay.Amnesia: Pathologic partial or complete loss of the ability to recall past experiences (AMNESIA, RETROGRADE) or to form new memories (AMNESIA, ANTEROGRADE). This condition may be of organic or psychologic origin. Organic forms of amnesia are usually associated with dysfunction of the DIENCEPHALON or HIPPOCAMPUS. (From Adams et al., Principles of Neurology, 6th ed, pp426-7)Ego: The conscious portion of the personality structure which serves to mediate between the demands of the primitive instinctual drives, (the id), of internalized parental and social prohibitions or the conscience, (the superego), and of reality.Empathy: An individual's objective and insightful awareness of the feelings and behavior of another person. It should be distinguished from sympathy, which is usually nonobjective and noncritical. It includes caring, which is the demonstration of an awareness of and a concern for the good of others. (From Bioethics Thesaurus, 1992)Neurosurgical Procedures: Surgery performed on the nervous system or its parts.Rest: Freedom from activity.Affect: The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Obsessive-Compulsive Disorder: An anxiety disorder characterized by recurrent, persistent obsessions or compulsions. Obsessions are the intrusive ideas, thoughts, or images that are experienced as senseless or repugnant. Compulsions are repetitive and seemingly purposeful behavior which the individual generally recognizes as senseless and from which the individual does not derive pleasure although it may provide a release from tension.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Parahippocampal Gyrus: A convolution on the inferior surface of each cerebral hemisphere, lying between the hippocampal and collateral sulci.Perceptual Disorders: Cognitive disorders characterized by an impaired ability to perceive the nature of objects or concepts through use of the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory, or sensory stimuli presented from one side of the body.Tomography, Optical: Projection of near-IR light (INFRARED RAYS), in the 700-1000 nm region, across an object in parallel beams to an array of sensitive photodetectors. This is repeated at various angles and a mathematical reconstruction provides three dimensional MEDICAL IMAGING of tissues. Based on the relative transparency of tissues to this spectra, it has been used to monitor local oxygenation, brain and joints.Evoked Potentials, Visual: The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.Neuronavigation: Intraoperative computer-assisted 3D navigation and guidance system generally used in neurosurgery for tracking surgical tools and localize them with respect to the patient's 3D anatomy. The pre-operative diagnostic scan is used as a reference and is transferred onto the operative field during surgery.Informatics: The field of information science concerned with the analysis and dissemination of data through the application of computers.Meningeal Neoplasms: Benign and malignant neoplastic processes that arise from or secondarily involve the meningeal coverings of the brain and spinal cord.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.Hydrocephalus: Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, INTRACRANIAL HYPERTENSION; HEADACHE; lethargy; URINARY INCONTINENCE; and ATAXIA.Pick Disease of the Brain: A rare form of DEMENTIA that is sometimes familial. Clinical features include APHASIA; APRAXIA; CONFUSION; ANOMIA; memory loss; and personality deterioration. This pattern is consistent with the pathologic findings of circumscribed atrophy of the poles of the FRONTAL LOBE and TEMPORAL LOBE. Neuronal loss is maximal in the HIPPOCAMPUS, entorhinal cortex, and AMYGDALA. Some ballooned cortical neurons contain argentophylic (Pick) bodies. (From Brain Pathol 1998 Apr;8(2):339-54; Adams et al., Principles of Neurology, 6th ed, pp1057-9)Judgment: The process of discovering or asserting an objective or intrinsic relation between two objects or concepts; a faculty or power that enables a person to make judgments; the process of bringing to light and asserting the implicit meaning of a concept; a critical evaluation of a person or situation.Meningioma: A relatively common neoplasm of the CENTRAL NERVOUS SYSTEM that arises from arachnoidal cells. The majority are well differentiated vascular tumors which grow slowly and have a low potential to be invasive, although malignant subtypes occur. Meningiomas have a predilection to arise from the parasagittal region, cerebral convexity, sphenoidal ridge, olfactory groove, and SPINAL CANAL. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2056-7)Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Age of Onset: The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.Geriatric Psychiatry: A subspecialty of psychiatry concerned with the mental health of the aged.Comprehension: The act or fact of grasping the meaning, nature, or importance of; understanding. (American Heritage Dictionary, 4th ed) Includes understanding by a patient or research subject of information disclosed orally or in writing.Language Tests: Tests designed to assess language behavior and abilities. They include tests of vocabulary, comprehension, grammar and functional use of language, e.g., Development Sentence Scoring, Receptive-Expressive Emergent Language Scale, Parsons Language Sample, Utah Test of Language Development, Michigan Language Inventory and Verbal Language Development Scale, Illinois Test of Psycholinguistic Abilities, Northwestern Syntax Screening Test, Peabody Picture Vocabulary Test, Ammons Full-Range Picture Vocabulary Test, and Assessment of Children's Language Comprehension.Pattern Recognition, Automated: In INFORMATION RETRIEVAL, machine-sensing or identification of visible patterns (shapes, forms, and configurations). (Harrod's Librarians' Glossary, 7th ed)Motor Cortex: Area of the FRONTAL LOBE concerned with primary motor control located in the dorsal PRECENTRAL GYRUS immediately anterior to the central sulcus. It is comprised of three areas: the primary motor cortex located on the anterior paracentral lobule on the medial surface of the brain; the premotor cortex located anterior to the primary motor cortex; and the supplementary motor area located on the midline surface of the hemisphere anterior to the primary motor cortex.Nervous System Malformations: Structural abnormalities of the central or peripheral nervous system resulting primarily from defects of embryogenesis.Decision Making: The process of making a selective intellectual judgment when presented with several complex alternatives consisting of several variables, and usually defining a course of action or an idea.Fear: The affective response to an actual current external danger which subsides with the elimination of the threatening condition.Organ Size: The measurement of an organ in volume, mass, or heaviness.Apolipoprotein E4: A major and the second most common isoform of apolipoprotein E. In humans, Apo E4 differs from APOLIPOPROTEIN E3 at only one residue 112 (cysteine is replaced by arginine), and exhibits a lower resistance to denaturation and greater propensity to form folded intermediates. Apo E4 is a risk factor for ALZHEIMER DISEASE and CARDIOVASCULAR DISEASES.Cluster Headache: A primary headache disorder that is characterized by severe, strictly unilateral PAIN which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial SWEATING, eyelid EDEMA, and miosis. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Brain Injury, Chronic: Conditions characterized by persistent brain damage or dysfunction as sequelae of cranial trauma. This disorder may result from DIFFUSE AXONAL INJURY; INTRACRANIAL HEMORRHAGES; BRAIN EDEMA; and other conditions. Clinical features may include DEMENTIA; focal neurologic deficits; PERSISTENT VEGETATIVE STATE; AKINETIC MUTISM; or COMA.Databases, Factual: Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.Sagittal Sinus Thrombosis: Formation or presence of a blood clot (THROMBUS) in the SUPERIOR SAGITTAL SINUS or the inferior sagittal sinus. Sagittal sinus thrombosis can result from infections, hematological disorders, CRANIOCEREBRAL TRAUMA; and NEUROSURGICAL PROCEDURES. Clinical features are primarily related to the increased intracranial pressure causing HEADACHE; NAUSEA; and VOMITING. Severe cases can evolve to SEIZURES or COMA.Radiopharmaceuticals: Compounds that are used in medicine as sources of radiation for radiotherapy and for diagnostic purposes. They have numerous uses in research and industry. (Martindale, The Extra Pharmacopoeia, 30th ed, p1161)tau Proteins: Microtubule-associated proteins that are mainly expressed in neurons. Tau proteins constitute several isoforms and play an important role in the assembly of tubulin monomers into microtubules and in maintaining the cytoskeleton and axonal transport. Aggregation of specific sets of tau proteins in filamentous inclusions is the common feature of intraneuronal and glial fibrillar lesions (NEUROFIBRILLARY TANGLES; NEUROPIL THREADS) in numerous neurodegenerative disorders (ALZHEIMER DISEASE; TAUOPATHIES).Epilepsy, Temporal Lobe: A localization-related (focal) form of epilepsy characterized by recurrent seizures that arise from foci within the temporal lobe, most commonly from its mesial aspect. A wide variety of psychic phenomena may be associated, including illusions, hallucinations, dyscognitive states, and affective experiences. The majority of complex partial seizures (see EPILEPSY, COMPLEX PARTIAL) originate from the temporal lobes. Temporal lobe seizures may be classified by etiology as cryptogenic, familial, or symptomatic (i.e., related to an identified disease process or lesion). (From Adams et al., Principles of Neurology, 6th ed, p321)Famous PersonsIntelligence Tests: Standardized tests that measure the present general ability or aptitude for intellectual performance.Social Perception: The perceiving of attributes, characteristics, and behaviors of one's associates or social groups.