Arousal: Cortical vigilance or readiness of tone, presumed to be in response to sensory stimulation via the reticular activating system.Sleep Arousal Disorders: Sleep disorders characterized by impaired arousal from the deeper stages of sleep (generally stage III or IV sleep).Erotica: Literary or artistic items having an erotic theme. It refers especially to books treating sexual love in a sensuous or voluptuous manner. (Webster, 3d ed)Sleep Stages: Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; includes Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Libido: The psychic drive or energy associated with sexual instinct in the broad sense (pleasure and love-object seeking). It may also connote the psychic energy associated with instincts in general that motivate behavior.Hibernation: The dormant state in which some warm-blooded animal species pass the winter. It is characterized by narcosis and by sharp reduction in body temperature and metabolic activity and by a depression of vital signs.Polysomnography: Simultaneous and continuous monitoring of several parameters during sleep to study normal and abnormal sleep. The study includes monitoring of brain waves, to assess sleep stages, and other physiological variables such as breathing, eye movements, and blood oxygen levels which exhibit a disrupted pattern with sleep disturbances.Wakefulness: A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.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.Galvanic Skin Response: A change in electrical resistance of the skin, occurring in emotion and in certain other conditions.Sleep, REM: A stage of sleep characterized by rapid movements of the eye and low voltage fast pattern EEG. It is usually associated with dreaming.Emotions: Those affective states which can be experienced and have arousing and motivational properties.Orgasm: The climax of sexual excitement in either humans or animals.Photoplethysmography: Plethysmographic determination in which the intensity of light reflected from the skin surface and the red cells below is measured to determine the blood volume of the respective area. There are two types, transmission and reflectance.Somnambulism: A parasomnia characterized by a partial arousal that occurs during stage IV of non-REM sleep. Affected individuals exhibit semipurposeful behaviors such as ambulation and are difficult to fully awaken. Children are primarily affected, with a peak age range of 4-6 years.Sciuridae: A family of the order Rodentia which contains 49 genera. Some of the more common genera are MARMOTA, which includes the marmot and woodchuck; Sciurus, the gray squirrel, S. carolinensis, and the fox squirrel, S. niger; Tamias, the eastern and western chipmunk; and Tamiasciurus, the red squirrel. The flying squirrels, except the scaly-tailed Anomaluridae, also belong to this family.Sleep Apnea Syndromes: Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.Sleep Apnea, Obstructive: A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac arrhythmias and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)Sexual Dysfunctions, Psychological: Disturbances in sexual desire and the psychophysiologic changes that characterize the sexual response cycle and cause marked distress and interpersonal difficulty. (APA, DSM-IV, 1994)Parasomnias: Movements or behaviors associated with sleep, sleep stages, or partial arousals from sleep that may impair sleep maintenance. Parasomnias are generally divided into four groups: arousal disorders, sleep-wake transition disorders, parasomnias of REM sleep, and nonspecific parasomnias. (From Thorpy, Sleep Disorders Medicine, 1994, p191)Respiratory Rate: The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Estivation: In certain living species, a period of dormancy during the summer months marked by decreased metabolism.Sleep Deprivation: The state of being deprived of sleep under experimental conditions, due to life events, or from a wide variety of pathophysiologic causes such as medication effect, chronic illness, psychiatric illness, or sleep disorder.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.Electrooculography: Recording of the average amplitude of the resting potential arising between the cornea and the retina in light and dark adaptation as the eyes turn a standard distance to the right and the left. The increase in potential with light adaptation is used to evaluate the condition of the retinal pigment epithelium.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Masturbation: Sexual stimulation or gratification of the self.Nocturnal Myoclonus Syndrome: Excessive periodic leg movements during sleep that cause micro-arousals and interfere with the maintenance of sleep. This condition induces a state of relative sleep deprivation which manifests as excessive daytime hypersomnolence. The movements are characterized by repetitive contractions of the tibialis anterior muscle, extension of the toe, and intermittent flexion of the hip, knee and ankle. (Adams et al., Principles of Neurology, 6th ed, p387)Hypothalamic Area, Lateral: Area in the hypothalamus bounded medially by the mammillothalamic tract and the anterior column of the FORNIX (BRAIN). The medial edge of the INTERNAL CAPSULE and the subthalamic region form its lateral boundary. It contains the lateral hypothalamic nucleus, tuberomammillary nucleus, lateral tuberal nuclei, and fibers of the MEDIAL FOREBRAIN BUNDLE.Autonomic Nervous System: The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.Orexin Receptors: G-protein-coupled NEUROPEPTIDE RECEPTORS that have specificity for OREXINS and play a role in appetite control, and sleep-wake cycles. Two principle receptor types exist, each having a specificity for OREXIN A and OREXIN B peptide subtypes.Locus Coeruleus: Bluish-colored region in the superior angle of the FOURTH VENTRICLE floor, corresponding to melanin-like pigmented nerve cells which lie lateral to the PERIAQUEDUCTAL GRAY.Respiration: The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).Clitoris: An erectile structure homologous with the penis, situated beneath the anterior labial commissure, partially hidden between the anterior ends of the labia minora.Pedophilia: A sexual disorder occurring in a person 16 years or older and that is recurrent with intense sexually arousing fantasies, sexual urges, or behaviors involving sexual activity with a prepubescent child (generally age 13 or younger). (from APA, DSM-IV, 1994).Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Receptors, Neuropeptide: Cell surface receptors that bind specific neuropeptides with high affinity and trigger intracellular changes influencing the behavior of cells. Many neuropeptides are also hormones outside of the nervous system.Penile Erection: The state of the PENIS when the erectile tissue becomes filled or swollen (tumid) with BLOOD and causes the penis to become rigid and elevated. It is a complex process involving CENTRAL NERVOUS SYSTEM; PERIPHERAL NERVOUS SYSTEMS; HORMONES; SMOOTH MUSCLES; and vascular functions.Habituation, Psychophysiologic: The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.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.Respiratory Physiological Phenomena: Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.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.Plethysmography: Recording of change in the size of a part as modified by the circulation in it.Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Night Terrors: A disorder characterized by incomplete arousals from sleep associated with behavior suggesting extreme fright. This condition primarily affects children and young adults and the individual generally has no recall of the event. Episodes tend to occur during stage III or IV. SOMNAMBULISM is frequently associated with this condition. (Adams et al., Principles of Neurology, 6th ed, p391)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.Sexual Dysfunction, Physiological: Physiological disturbances in normal sexual performance in either the male or the female.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.Trazodone: A serotonin uptake inhibitor that is used as an antidepressive agent. It has been shown to be effective in patients with major depressive disorders and other subsets of depressive disorders. It is generally more useful in depressive disorders associated with insomnia and anxiety. This drug does not aggravate psychotic symptoms in patients with schizophrenia or schizoaffective disorders. (From AMA Drug Evaluations Annual, 1994, p309)Reaction Time: The time from the onset of a stimulus until a response is observed.Hypothalamic Hormones: Peptide hormones produced by NEURONS of various regions in the HYPOTHALAMUS. They are released into the pituitary portal circulation to stimulate or inhibit PITUITARY GLAND functions. VASOPRESSIN and OXYTOCIN, though produced in the hypothalamus, are not included here for they are transported down the AXONS to the POSTERIOR LOBE OF PITUITARY before being released into the portal circulation.Prone Position: The posture of an individual lying face down.Doxapram: A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)Sleep Apnea, Central: A condition associated with multiple episodes of sleep apnea which are distinguished from obstructive sleep apnea (SLEEP APNEA, OBSTRUCTIVE) by the complete cessation of efforts to breathe. This disorder is associated with dysfunction of central nervous system centers that regulate respiration.Circadian Rhythm: The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.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.Stress, Psychological: Stress wherein emotional factors predominate.