Hallucinations

Hallucinations exist when the mind has a sensory experience (auditory, visual, etc.) in the absence of an external stimulus; it is forcing a sensation as though it is real when there is nothing to be perceived. They may be mild distortions or they can go beyond the normal range of most experiences to immersing visions, sounds, smells and anything else one might imagine. Hallucinations are commonly tied to psychiatric disorders, especially schizophrenia; however, they can stem from a range of causes including sleep deprivation, neurological conditions (e.g., Alzheimer’s disease), emotional distress and even certain cultural or spiritual practices. Each type has its own unique traits and surprising triggers, which we explore here.

Hallucinations and Other Things Caused by Fasting

Hallucination due to Fasting Any perceptual experience including hunger and thirst that occurs with fasting more prolonged period of time. Fasting has been a part of spiritual practices in many cultures for thousands of years, since it induces an altered state of consciousness. Fasting influences brain chemistry, for example glucose and neurotransmitters. Those sensory distortions can include everything from seeing flashing lights to an elaborate vision with spiritual or mystical meaning. Assumed to be generated by a brain that is starving of nutrients essential for high-level processing in the frontal cortex, such hallucinations disturb normal ongoing thought and sensory processing.

Auditory Pareidolia

Auditory pareidolia occurs when sounds constitute from random or background noise to misinterpretation as voices or other meaningful auditory cues. This inherent feature emerges when the brain, operating in an uncertain or noisy world, unconsciously looks for familiar structures. To illustrate — a person might hear a song or conversation in the sound of an air conditioner or radio static. Auditory pareidolia or merely a sensory misperception, technically not a hallucination (in the true clinical sense) because this process means that sounds are making their way to one ear or another but only maladaptive wiring in the brain that leads it misinterpreted the signals arriving inside instead of generating inexplicable sound. Still it is an example of what influence behaviour and ambient sounds in the meeting room might play on perception and expectation.

Sound Photism

Sound photism (also named as auditory-visual synesthesia) is when sounds are visualized with some color or pattern. Those with sound photism may see flashes of color or shapes when exposed to certain sounds—the most common being musical notes, followed by human voices. Synesthesia in this way occurs because the synesthetic wires cross in the brain's sensory-processing regions, allowing auditory and visual areas to communicate more freely. In people with this condition, everyday sounds may trigger elaborate light shows, which creates a special synesthetic experience by overlapping visual and auditory stimuli.

Sound Seeing

Sound seeing is a kind of synesthesia where sounds conjure up vivid images. Sound seeing is less of a reflexive experience than sound photism — though with practice, the visualization might happen in a more organic fashion. A once opposite but related example is auditory imagery caused by annotative audio or a music, inducing ostensive imagery (or imagery of scenes) in mind’s eye. The musicians who write cinematic or orchestral music might have sound seeing since they convert sounds to visuals. As such, this experience is often employed productively in art but sometimes appears randomly triggered by some noise.

Phonemic Chromesthesia

Chromatic phonemic synesthesia is when colors are evoked by sounds (i.e., spoken words or phonemes, which are basic sounds). These synesthetes might associate a certain sound or letter with a certain color, intertwining language and color perception. Scholars believe that this phenomenon is a result of atypical wiring between the regions of semantic processing and color perception areas in the brain. People with chromatic phonemic synesthesia may be treated to a particularly colourful chat.

Phonopsia

Phonopsia is a phenomenon when sounds represent light flashes or other visual experiences. Phonopsia, like sound photism, is when it mixes between auditory and visual stimulation but phonopsia does so through loud sounds or unexpected noises. This just-creepy-enough phenomenon combines unrelated stimuli into a sensory mismatch, where hearing and sight overlap in disarray. It is actually a condition in which the brain misinterprets noise (as sound itself does note have innate meaning until the brain interprets it) rather spontaneously or due to certain neurological conditions and reflects how sensory information can be misperceived by human brains.

Presence or Sensed Presence (Anwesenheit)

Anwesenheit (perception of presence, or sensed presence), is a feeling that another human being or humanoid presence is nearby when there are none present physically. Sensed presence, a feeling of another person nearby; it is said to be a function of unusual brain activity (possibly in the temporal lobe) and often experienced in isolation, extreme environments, or times of sleep paralysis. Scenarios like this happen a lot to explorers, climbers and people under excruciating pressure — the surprise is not uncommon when men and women in jeopardy feel exposed or deprived preventative; but they almost never talk about it. Sometimes the sensed presence is comforting, sometimes terrifying — again, it depends on the context and who is involved.

Erotic Hallucinations

In other words, a person experiences sexual sensations or even engages in sexual intercourse with someone when no such thing is really happening — and this phenomenon is referred to as erotic hallucination. Such hallucinations may take place in sleep, especially during periods of REM sleep, or while awake caused by neurological disturbances, hormone changes and some psychiatric conditions. For the people who experience erotic hallucinations, these may be very intense and intrusive, potentially turning into nightmares. They point to the deep intertwining of sensory and emotional perception and how this can express involuntarily in certain mental states.

Negative Autoscopy

Negative autoscopy: looking in a mirror, not seeing oneself—self-erasure. While a visual hallucination is one sees something which is absent, negative autoscopy can be viewed as the opposite condition – detects imperceptibility of what ought to be perceptible. It feels disturbingly alien, because it interferes with his self-perception — the ability to here and now recognize oneself as a person inhabiting one’s own body.] For this reason it is often linked to severe depersonalization and neurological conditions, emphasizing the fragile complexity of self-image in perception.

Pre-Lucid Dream

A pre-lucid dream is a state of lucidity in a dream preceding awareness, where the dreamer feels like they may be dreaming but has not reached full awareness. During this stage, dreamers may experience discrepancies in the dream setting or contemplate their reality. This is not a hallucination in the traditional sense, but rather an experience that challenges the perception of reality during lucid dreams: Here you exist within and outside the world of tangible sensation. Lucid dreamers will even practice recognizing times like these so that they can flip into full lucidity.

Gedankenhören

Gedankenhören (pronounced goat-hank-er-uh), which is German for "thought-hearing", is a perceptual phenomenon that seems so common, most of us experience it in some form. This sound you hear could be the brain turning one of those internal thoughts audible for a period, especially through stress or fatigue. Thought hearing, or gedankenhören (the latter is a neologism) as it is usually not permanent ánd context-specific. Similar to auditory hallucinations in schizophrenia but different in the sense that these type of readings are transient. It gives an understanding of the brain's way of separating sounds derived from internally generated signals or externally produced signals, and where this line can sometimes become less distinct.

Bereavement Hallucinations

When someone sees or feels a dead relative near her, almost always they are sensations (bereavement hallucinations) that imply we perceive the presence of the deceased person. Such hallucinations often happen in people with a major loss — seeing the person, hearing his or her voice, or feeling that he/she touched. These experiences are normally reassuring rather than distressing and are believed to assist with bereavement. They highlight the ability of the brain to generate neuron patterns as if a sensory experience is taking place, particularly under emotional stress.

Twilight State

Twilight state which is commonly present with temporal lobe epilepsy in which one may have distorted experience of visual and auditory or sensory hallucinations. In a dual realm of dreaming, perception becomes hallucinatory; some sensory input is abstract and mixed with reality. That state, which is now called postictal and which often comes after (and before) a seizure to describe someone who is confused, depersonalized or has memory disturbances. Twilight states, as TW and co note, expose the brain to intermittent sensory illusion (Hallucination), hardwired by the history of neurological disturbance.

Negative Heautoscopy

In negative heautoscopy, they see a double — or "dopplegänger" -- of themselves but do not carry the subjective feeling of being in that body. Positive heautoscopy recognizes the double as self, while negative creates a feeling of strangeness. It can be a traumatic experience leading the person to have an experience of fragmentation. Heautoscopy is negative in nature and frequently happens in dissociative or neurological processes, revealing the complexities of the mind within construction and stabilizing a stable self-identity (Cuypers et al.

Asomatoscopy

Asomatoscopy — A rare kind of hallucination in which the patient imagines or sees himself as invisible or without a body. Asomatoscopy — popularly viewed as absolute dissociation or extreme neurological pathology — injures body image and other mind-body sensations of presence in the vehicle. It may relate to conditions such as depersonalization disorder, when you feel detached from your body; or neurological problems with awareness of the body.

Other Types of Hallucinations

Beyond these well-characterized forms, there are multiple other varieties of hallucination, each highlighting different features of sensory and cognitive processing.

Taste Hallucinations (ThisType relates to tase things that are not there, often seen with seizures or as an adverse effect of a drug.) Its taste can be pleasing or unpleasent like a metallicor sweet tastes.

Olfactory Hallucinations — This refers to smelling things that are not present, which may be activated by epilepsy and migraines. Many of these scents are strange, such as burning rubber or decomposing food.

Hypnagogic and Hypnopompic Hallucinations: Occurs when drifting off (hypnagogic) oneor waking up (hypnopompic), accompanied by dynamic visualizations, sounds or feelings. If you have ever experienced a hypnagogic hallucination yourself, you probably know they can seem extremely real — so much so that many people think the stuff they see is actually happening.

Lilliputian Hallucinations: A rare type of visual hallucination characterized by small people or animals usually perceived to be playful, like trickster animals. It is occasionally connected with drug use or brain disease, as it reflects a type of change in the size perception of the organism (a.k.a it's mind).

Tactile Hallucinations — Tactile hallucinations are defined as feeling things on or under the skin, such as insects crawling. This may happen in withdrawal syndromes or some psychiatric disorders.

The different types of these hallucinations emphasize our brain ability to create vivid lifelike events without any external stimulation, showcasing the complex interactions between perception, memory and emotion.