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.

A false belief regarding the self or persons or objects outside the self that persists despite the facts, and is not considered tenable by one's associates.

A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.

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.

Study of mental processes and behavior of schizophrenics.

Disorders in which there is a loss of ego boundaries or a gross impairment in reality testing with delusions or prominent hallucinations. (From DSM-IV, 1994)

A chronic form of schizophrenia characterized primarily by the presence of persecutory or grandiose delusions, often associated with hallucination.

The artificial language of schizophrenic patients - neologisms (words of the patient's own making with new meanings).

A group of mental disorders associated with organic brain damage and caused by poisoning from alcohol.

Psychotic organic mental disorders resulting from the toxic effect of drugs and chemicals or other harmful substance.

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.

The process whereby auditory stimuli are selected, organized, and interpreted by the organism.

The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.

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.

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.

Standardized procedures utilizing rating scales or interview schedules carried out by health personnel for evaluating the degree of mental illness.

Disturbances in mental processes related to learning, thinking, reasoning, and judgment.

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.

A common condition characterized by transient partial or total paralysis of skeletal muscles and areflexia that occurs upon awakening from sleep or less often while falling asleep. Stimuli such as touch or sound may terminate the episode, which usually has a duration of seconds to minutes. This condition may occur in normal subjects or be associated with NARCOLEPSY; CATAPLEXY; and hypnagogic HALLUCINATIONS. The pathophysiology of this condition is closely related to the normal hypotonia that occur during REM sleep. (From Adv Neurol 1995;67:245-271)

Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.

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.

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.

A neurodegenerative disease characterized by dementia, mild parkinsonism, and fluctuations in attention and alertness. The neuropsychiatric manifestations tend to precede the onset of bradykinesia, MUSCLE RIGIDITY, and other extrapyramidal signs. DELUSIONS and visual HALLUCINATIONS are relatively frequent in this condition. Histologic examination reveals LEWY BODIES in the CEREBRAL CORTEX and BRAIN STEM. SENILE PLAQUES and other pathologic features characteristic of ALZHEIMER DISEASE may also be present. (From Neurology 1997;48:376-380; Neurology 1996;47:1113-1124)