Alliesthesia describes the dependence of the perception of pleasure or disgust perceived when consuming a stimulus

Stimulus (physiology)

In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....

 on the "milieu intérieur

Milieu interieur

Milieu intérieur or interior milieu, from the French, milieu intérieur, is a term coined by Claude Bernard to refer to the extra-cellular fluid environment, and its physiological capacity to ensure protective stability for the tissues and organs of multicellular living organisms.-Origin:Claude...

" of the organism. Therefore, a stimulus capable of ameliorating the state of the interior milieu, will be perceived as pleasant. In contrary, a stimulus disturbing the milieu interne of the organism will be perceived as unpleasant or even painful. The sensation elicited therefore depends not only on the quality or on the intensity of the stimulus, but also on internal receptors

Sensory receptor

In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...

, and is subjective

Subjectivity

Subjectivity refers to the subject and his or her perspective, feelings, beliefs, and desires. In philosophy, the term is usually contrasted with objectivity.-Qualia:...

.

Alliesthesia is a physiologic

Physiology

Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 phenomenon

Phenomenon

A phenomenon , plural phenomena, is any observable occurrence. Phenomena are often, but not always, understood as 'appearances' or 'experiences'...

 and should not be confounded with the pathologic

Pathology

Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....

 symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

 of allesthesia.
Another phenomenon based on sensory cues and not to be confound with alliesthesia is "sensory-specific satiety

Sensory-specific satiety

Sensory-specific satiety is a sensory hedonic phenomenon that refers to the declining satisfaction generated by the consumption of a certain type of food, and the consequent renewal in appetite resulting from the exposure to a new flavor or food. The phenomenon was first described in 1956 by the...

".

Forms of alliesthesia

• thermic alliesthesia: alliesthesia of the thermic perception (heat and cold) - she contributes fundamentally to homeostatic
  Homeostasis
  Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
  
   thermoregulation
  Thermoregulation
  Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
  
  
• olfactory alliesthesia: alliesthesia of olfaction
  Olfaction
  Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
  
   (sense of smell
  Smell
  Smell may refer to:* Olfaction, sense of smell, the ability of humans and other animals to perceive odors* Odor, the percept resultant from the sense of smell...
  
  )
• gustatory alliesthesia: alliesthesia of taste
  Taste
  Taste is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc....
  
   - see primary tastes
  Taste
  Taste is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc....
  
   (sweet, salty, bitter, acid, umami
  Umami
  Umami , popularly referred to as savoriness, is one of the five basic tastes together with sweet, sour, bitter, and salty.-Etymology:Umami is a loanword from the Japanese meaning "pleasant savory taste". This particular writing was chosen by Professor Kikunae Ikeda from umai "delicious" and mi ...
  
   and "calcium
  Calcium
  Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
  
  ")
• olfacto-gustatory alliesthesia or alimentary alliesthesia: alliesthesia of tastes/flavors pertaining to food intake
• visual/optic alliesthesia: alliesthesia of vision
  Visual perception
  Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
  
  
• auditory alliesthesia: alliesthesia of the sense of hearing
  Hearing (sense)
  Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
  
  

Each of these forms of alliesthesia exists in two opposite tendencies:

• negative alliesthesia: transformation of the sensation from pleasure to displeasure
• positive alliesthesia: transformation of the sensation from displeasure to pleasure

Discovery

The founder of the phenomenon of alliesthesia is the French physiologist Michel Cabanac. The first scientific publication from 1968 was succeeded by over 40 publications in international journals, for example: 1970 in Nature

Nature (journal)

Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

and 1971 in Science

Science Magazine

Science Magazine was a half-hour television show produced by the Canadian Broadcasting Corporation from 1975 to 1979.The show was hosted by geneticist David Suzuki, who previously hosted the daytime youth programme Suzuki On Science...

.
The term alliesthesia was first mentioned in the annex of Physiological Role of Pleasure and has been chosen in collaboration with the coauthor Stylianos Nicolaïdis. Originally, alliesthesia has been discovered by experiment

Experiment

An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...

s in human subjects, and later been confirmed in rats (Rattus norvegicus).