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.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Evoked Potentials, Auditory: The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.Auditory Cortex: The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.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.Cortical Synchronization: EEG phase synchronization of the cortical brain region (CEREBRAL CORTEX).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.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Brain Waves: Wave-like oscillations of electric potential between parts of the brain recorded by EEG.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.Alpha Rhythm: Brain waves characterized by a relatively high voltage or amplitude and a frequency of 8-13 Hz. They constitute the majority of waves recorded by EEG registering the activity of the parietal and occipital lobes when the individual is awake, but relaxed with the eyes closed.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.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.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.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.Somatosensory Cortex: Area of the parietal lobe concerned with receiving sensations such as movement, pain, pressure, position, temperature, touch, and vibration. It lies posterior to the central sulcus.Contingent Negative Variation: A negative shift of the cortical electrical potentials that increases over time. It is associated with an anticipated response to an expected stimulus and is an electrical event indicative of a state of readiness or expectancy.Reaction Time: The time from the onset of a stimulus until a response is observed.Magnetocardiography: The measurement of magnetic fields generated by electric currents from the heart. The measurement of these fields provides information which is complementary to that provided by ELECTROCARDIOGRAPHY.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.Evoked Potentials, Somatosensory: The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.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)Evoked Potentials, Visual: The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.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.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.Beta Rhythm: Brain waves with frequency between 15-30 Hz seen on EEG during wakefulness and mental activity.Epilepsies, Partial: Conditions characterized by recurrent paroxysmal neuronal discharges which arise from a focal region of the brain. Partial seizures are divided into simple and complex, depending on whether consciousness is unaltered (simple partial seizure) or disturbed (complex partial seizure). Both types may feature a wide variety of motor, sensory, and autonomic symptoms. Partial seizures may be classified by associated clinical features or anatomic location of the seizure focus. A secondary generalized seizure refers to a partial seizure that spreads to involve the brain diffusely. (From Adams et al., Principles of Neurology, 6th ed, pp317)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.ReadingPitch Perception: A dimension of auditory sensation varying with cycles per second of the sound stimulus.Word Association Tests: Lists of words to which individuals are asked to respond ascertaining the conceptual meaning held by the individual.Tinnitus: A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.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.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).Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.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.Touch Perception: The process by which the nature and meaning of tactile stimuli are recognized and interpreted by the brain, such as realizing the characteristics or name of an object being touched.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.Delta Rhythm: Brain waves seen on EEG characterized by a high amplitude and a frequency of 4 Hz and below. They are considered the "deep sleep waves" observed during sleep in dreamless states, infancy, and in some brain disorders.Fingers: Four or five slender jointed digits in humans and primates, attached to each HAND.Landau-Kleffner Syndrome: A syndrome characterized by the onset of isolated language dysfunction in otherwise normal children (age of onset 4-7 years) and epileptiform discharges on ELECTROENCEPHALOGRAPHY. Seizures, including atypical absence (EPILEPSY, ABSENCE), complex partial (EPILEPSY, COMPLEX PARTIAL), and other types may occur. The electroencephalographic abnormalities and seizures tend to resolve by puberty. The language disorder may also resolve although some individuals are left with severe language dysfunction, including APHASIA and auditory AGNOSIA. (From Menkes, Textbook of Child Neurology, 5th ed, pp749-50; J Child Neurol 1997 Nov;12(8):489-495)Speech: Communication through a system of conventional vocal symbols.Dominance, Cerebral: Dominance of one cerebral hemisphere over the other in cerebral functions.Theta Rhythm: Brain waves characterized by a frequency of 4-7 Hz, usually observed in the temporal lobes when the individual is awake, but relaxed and sleepy.Language: A verbal or nonverbal means of communicating ideas or feelings.Frontal Lobe: The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus.Touch: Sensation of making physical contact with objects, animate or inanimate. Tactile stimuli are detected by MECHANORECEPTORS in the skin and mucous membranes.Epilepsy, Frontal Lobe: A localization-related (focal) form of epilepsy characterized by seizures which arise in the FRONTAL LOBE. A variety of clinical syndromes exist depending on the exact location of the seizure focus. Frontal lobe seizures may be idiopathic (cryptogenic) or caused by an identifiable disease process such as traumatic injuries, neoplasms, or other macroscopic or microscopic lesions of the frontal lobes (symptomatic frontal lobe seizures). (From Adams et al., Principles of Neurology, 6th ed, pp318-9)Noise: Any sound which is unwanted or interferes with HEARING other sounds.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.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Psychoacoustics: The science pertaining to the interrelationship of psychologic phenomena and the individual's response to the physical properties of sound.Dyslexia: A cognitive disorder characterized by an impaired ability to comprehend written and printed words or phrases despite intact vision. This condition may be developmental or acquired. Developmental dyslexia is marked by reading achievement that falls substantially below that expected given the individual's chronological age, measured intelligence, and age-appropriate education. The disturbance in reading significantly interferes with academic achievement or with activities of daily living that require reading skills. (From DSM-IV)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.Hand: The distal part of the arm beyond the wrist in humans and primates, that includes the palm, fingers, and thumb.Music: Sound that expresses emotion through rhythm, melody, and harmony.Auditory Perceptual Disorders: Acquired or developmental cognitive disorders of AUDITORY PERCEPTION characterized by a reduced ability to perceive information contained in auditory stimuli despite intact auditory pathways. Affected individuals have difficulty with speech perception, sound localization, and comprehending the meaning of inflections of speech.Anticipation, Psychological: The ability to foresee what is likely to happen on the basis of past experience. It is largely a frontal lobe function.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Visual Cortex: Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.Pattern Recognition, Physiological: The analysis of a critical number of sensory stimuli or facts (the pattern) by physiological processes such as vision (PATTERN RECOGNITION, VISUAL), touch, or hearing.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Semantics: The relationships between symbols and their meanings.Periodicity: The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).Scalp: The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL).Phonetics: The science or study of speech sounds and their production, transmission, and reception, and their analysis, classification, and transcription. (Random House Unabridged Dictionary, 2d ed)Neuroimaging: Non-invasive methods of visualizing the CENTRAL NERVOUS SYSTEM, especially the brain, by various imaging modalities.Pitch Discrimination: The ability to differentiate tones.Behavior: The observable response of a man or animal to a situation.Auditory Pathways: NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.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.Mental Processes: Conceptual functions or thinking in all its forms.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Rest: Freedom from activity.Artifacts: Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.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.Pattern Recognition, Visual: Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.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.Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.Verbal Behavior: Includes both producing and responding to words, either written or spoken.Data Interpretation, Statistical: Application of statistical procedures to analyze specific observed or assumed facts from a particular study.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Sound: A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.
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