Neurobehavioral Manifestations: Signs and symptoms of higher cortical dysfunction caused by organic conditions. These include certain behavioral alterations and impairments of skills involved in the acquisition, processing, and utilization of knowledge or information.Habituation, Psychophysiologic: The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.Psychophysiology: The study of the physiological basis of human and animal behavior.Psychophysiologic Disorders: A group of disorders characterized by physical symptoms that are affected by emotional factors and involve a single organ system, usually under AUTONOMIC NERVOUS SYSTEM control. (American Psychiatric Glossary, 1988)Startle Reaction: A complex involuntary response to an unexpected strong stimulus usually auditory in nature.Exploratory Behavior: The tendency to explore or investigate a novel environment. It is considered a motivation not clearly distinguishable from curiosity.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Behavior, Animal: The observable response an animal makes to any situation.Galvanic Skin Response: A change in electrical resistance of the skin, occurring in emotion and in certain other conditions.Escape Reaction: Innate response elicited by sensory stimuli associated with a threatening situation, or actual confrontation with an enemy.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Smell: The ability to detect scents or odors, such as the function of OLFACTORY RECEPTOR NEURONS.Odors: The volatile portions of substances perceptible by the sense of smell. (Grant & Hackh's Chemical Dictionary, 5th ed)Aplysia: An opisthobranch mollusk of the order Anaspidea. It is used frequently in studies of nervous system development because of its large identifiable neurons. Aplysiatoxin and its derivatives are not biosynthesized by Aplysia, but acquired by ingestion of Lyngbya (seaweed) species.Latency Period (Psychology): The period from about 5 to 7 years to adolescence when there is an apparent cessation of psychosexual development.Avoidance Learning: A response to a cue that is instrumental in avoiding a noxious experience.Repression-Sensitization: Defense mechanisms involving approach and avoidance responses to threatening stimuli. The sensitizing process involves intellectualization in approaching or controlling the stimulus whereas repression involves unconscious denial in avoiding the stimulus.Migraine Disorders: A class of disabling primary headache disorders, characterized by recurrent unilateral pulsatile headaches. The two major subtypes are common migraine (without aura) and classic migraine (with aura or neurological symptoms). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Restraint, Physical: Use of a device for the purpose of controlling movement of all or part of the body. Splinting and casting are FRACTURE FIXATION.Olfactory Perception: The process by which the nature and meaning of olfactory stimuli, such as odors, are recognized and interpreted by the brain.Migraine without Aura: Recurrent unilateral pulsatile headaches, not preceded or accompanied by an aura, in attacks lasting 4-72 hours. It is characterized by PAIN of moderate to severe intensity; aggravated by physical activity; and associated with NAUSEA and / or PHOTOPHOBIA and PHONOPHOBIA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Association Learning: The principle that items experienced together enter into a connection, so that one tends to reinstate the other.