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Visual Hallucinations
A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combination of 2 conscious states of brain wakefulness and REM sleep. They are distinguishable from several related phenomena, such as dreaming (REM sleep), which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and mental imagery, which does not mimic real perception, and is under voluntary control. Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpreted stimulus (i.e., a real perception) is given some additional significance. Many hallucinations happen also during sleep paralyses. Hallucinations can occur in any sensory modality—visual, auditory, olfact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
August Natterer
August Natterer (3 August 1868 – 7 October 1933), also known as Neter, was a German outsider artist with schizophrenia. Biography August Natterer, given the pseudonym ''Neter'' by his psychiatrist to protect him and his family from the intense social stigma associated with mental illness at the time, was born on 3 August 1868 in Schornreute near Ravensburg, Germany, the son of a clerk and the youngest of nine children. Natterer studied engineering, got married, travelled widely and had a successful career as an electrician, but was suddenly stricken with delusions and anxiety attacks. On 1 April 1907, he had a pivotal hallucination of the Last Judgment during which "10,000 images flashed by in half an hour". He described it as follows: This ordeal led to a suicide attempt and committal to the first of what would be several mental asylums occupied during the remaining twenty-six years of his life. Natterer thereafter maintained that he was the illegitimate child of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprioception
Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons located within muscles, tendons, and joints. Most animals possess multiple subtypes of proprioceptors, which detect distinct kinematic parameters, such as joint position, movement, and load. Although all mobile animals possess proprioceptors, the structure of the sensory organs can vary across species. Proprioceptive signals are transmitted to the central nervous system, where they are integrated with information from other sensory systems, such as the visual system and the vestibular system, to create an overall representation of body position, movement, and acceleration. In many animals, sensory feedback from proprioceptors is essential for stabilizing body posture and coordinating body movement. System overview In vertebrates, limb ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurological Disorder
A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain and altered levels of consciousness. There are many recognized neurological disorders, some relatively common, but many rare. They may be assessed by neurological examination, and studied and treated within the specialities of neurology and clinical neuropsychology. Interventions foneurological disordersinclude preventive measures, lifestyle changes, physiotherapy or other therapy, neurorehabilitation, pain management, medication, operations performed by neurosurgeons or a specific diet. The World Health Organization estimated in 2006 that neurological disorders and their sequelae (direct consequences) affect as many as one billion people worldwide, and identified ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychosis
Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior that is inappropriate for a given situation. There may also be sleep problems, social withdrawal, lack of motivation, and difficulties carrying out daily activities. Psychosis can have serious adverse outcomes. As with many psychiatric phenomena, psychosis has several different causes. These include mental illness, such as schizophrenia or schizoaffective disorder, bipolar disorder, sensory deprivation and in rare cases, major depression (psychotic depression). Other causes include: trauma, sleep deprivation, some medical conditions, certain medications, and drugs such as cannabis, hallucinogens, and stimulants. One type, known as postpartum psychosis, can occur after giving birth. The neurotransmitter dopamine is believed to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep Deprivation
Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity. Acute sleep deprivation is when an individual sleeps less than usual or does not sleep at all for a short period of time – usually lasting one to two days. Chronic sleep deprivation means when an individual routinely sleeps less than an optimal amount for ideal functioning. Chronic sleep deficiency is often confused with the term insomnia. Although both chronic sleep deficiency and insomnia share decreased quantity and/or quality of sleep as well as impaired function, their difference lies in the ability to fall asleep. Sleep deprived individuals are able to fall asleep rapidly when allowed but those with insomnia have difficulty falling asleep. The average adult needs seven or more hours of sleep per night to mainta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deliriant
Deliriants are a subclass of hallucinogen. The term was coined in the early 1980s to distinguish these drugs from psychedelics and dissociatives such as LSD and ketamine, respectively, due to their primary effect of causing delirium, as opposed to the more lucid and less disturbed states produced by other types of hallucinogens.Duncan, D. F., and Gold, R. S. (1982). Drugs and the Whole Person. New York: John Wiley & Sons The term generally refers to anticholinergic drugs, which are substances that inhibit the function of the neurotransmitter acetylcholine. Common examples of deliriants include plants of the genera ''Datura'' and ''Brugmansia'' (both containing scopolamine) as well as higher than recommended dosages of diphenhydramine (Benadryl). A number of plant deliriants such as that of the Solanaceae family, particularly in the Americas have been used by some indigenous cultures to reach delirious and altered states for traditions or rituals, such as rites of passage, divin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychoactive Drug
A psychoactive drug, psychopharmaceutical, psychoactive agent or psychotropic drug is a chemical substance, that changes functions of the nervous system, and results in alterations in perception, mood, consciousness, cognition or behavior. These substances may be used medically, recreationally or spiritually to a. Purposefully improve one’s perceived performance b. Alter one's consciousness (such as with entheogens for ritual, spiritual or shamanic purposes) or c. For research. Some categories of psychoactive drugs - which are believed, by some, to have therapeutic value - may be prescribed by some physicians and other healthcare practitioners. Examples of medication categories that may contain potentially beneficial psychoactive drugs include, but are not limited to: # Anesthetics # Analgesics # Anticonvulsants # Anti-Parkinson’s medications # Medications used to treat Neuropsychiatric Disorders a. Antidepressants b. Anxiolytics c. Antipsychotics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypnopompia
Hypnopompia (also known as hypnopompic state) is the state of consciousness leading out of sleep, a term coined by the psychical researcher Frederic Myers. Its mirror is the hypnagogic state at sleep onset; though often conflated, the two states are not identical and have a different phenomenological character. Hypnopompic and hypnagogic hallucinations are frequently accompanied by sleep paralysis, which is a state wherein one is consciously aware of one's surroundings but unable to move or speak. Hallucinations Hallucinations are commonly understood as "sensory perceptions that occur in the absence of an objective stimulus". As this definition implies, though, like dreams, most hallucinations are visual, they can encompass a broader range of sensory experience. Auditory hallucinations are thus also common: "patients can hear simple sounds, structured melodies or complete sentences". Slightly less common but not unheard of are " somesthetic" hallucinations involving the sens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypnagogic Hallucination
Hypnagogia is the experience of the transitional state from wakefulness to sleep: the ''hypnagogic'' state of consciousness, during the onset of sleep. Its opposite state is described as the transitional state from sleep into wakefulness. Mental phenomena that may occur during this "threshold consciousness" phase include hypnagogic hallucinations, lucid thought, exploding head syndrome, lucid dreaming, and sleep paralysis. The latter two phenomena are themselves separate sleep conditions that are sometimes experienced during the hypnagogic state. Definitions The word ''hypnagogia'' is sometimes used in a restricted sense to refer to the onset of sleep, and contrasted with ''hypnopompia'', Frederic Myers's term for waking up. However, ''hypnagogia'' is also regularly employed in a more general sense that covers both falling asleep and waking up. Indeed, it is not always possible in practice to assign a particular episode of any given phenomenon to one or the other, given that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schizophrenia
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdrawal, decreased emotional expression, and apathy. Symptoms typically develop gradually, begin during young adulthood, and in many cases never become resolved. There is no objective diagnostic test; diagnosis is based on observed behavior, a history that includes the person's reported experiences, and reports of others familiar with the person. To be diagnosed with schizophrenia, symptoms and functional impairment need to be present for six months (DSM-5) or one month (ICD-11). Many people with schizophrenia have other mental disorders, especially substance use disorders, depressive disorders, anxiety disorders, and obsessive–compulsive disorder. About 0.3% to 0.7% of people are diagnosed with schizophrenia during their lifetime. In 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Vision
Peripheral vision, or ''indirect vision'', is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the visual field is included in the notion of peripheral vision. "Far peripheral" vision refers to the area at the edges of the visual field, "mid-peripheral" vision refers to medium eccentricities, and "near-peripheral", sometimes referred to as "para-central" vision, exists adjacent to the center of gaze. Boundaries Inner boundaries The inner boundaries of peripheral vision can be defined in any of several ways depending on the context. In everyday language the term "peripheral vision" is often used to refer to what in technical usage would be called "far peripheral vision." This is vision outside of the range of stereoscopic vision. It can be conceived as bounded at the center by a circle 60° in radius or 120° in diameter, centered arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Perception
The study of time perception or chronoception is a field within psychology, cognitive linguistics and neuroscience that refers to the subjective experience, or sense, of time, which is measured by someone's own perception of the duration of the indefinite and unfolding of events. The perceived time interval between two successive events is referred to as perceived duration. Though directly experiencing or understanding another person's perception of time is not possible, perception can be objectively studied and inference, inferred through a number of scientific experiments. Some temporal illusions help to expose the underlying neural mechanisms of time perception. Pioneering work, emphasizing species-specific differences, was conducted by Karl Ernst von Baer. Theories Time perception is typically categorized in three distinct ranges, because different ranges of duration are processed in different areas of the brain: * Sub-second timing or millisecond timing * Interval timing o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
