The receptors of the retina are sensitive to changes in the light reflected on objects; the ear ones, to the mechanical waves generated by interactions of objects; the smell and taste ones, to molecules with information about various elements of the environment, appetitive and/or adverse ...
There are light receptors, mechanical receptors, thermal receptors, chemical receptors... and there are also necrotic damage (consummated or imminent) receptors.
The body is packed with sensors-receptors of consummated necrosis, located in the membrane of specific neurons and immune system cells, vigilant, capable of detecting violent cell death (necrosis).
Receptors of the retina (photoreceptors) detect light, photons, and the vigilant neurons of necrosis (nociceptors) detect signs of necrosis. If there is no light, there is no activation of photoreceptors. If there is no necrosis, there will be no activation of necrosis sensors (truism).
The necrotic cell loses membrane integrity and internal chemicals are released. Necrosis receptors pick them up and the reaction ‘molecules-death---necrosis sensor’ generates an electrical signal that contains information about the deadly incident, an electrical signal that is carried by the neuron to various assessment and defensive response centers.
In threat of imminent but not consummated necrosis, neurons and immune vigilant cells detect dangerous agents and states: extreme temperatures, germs, mechanical stimuli, lack of oxygen, acids... Membrane sensors react to such agents and states and report the hazard and the need to respond to the threat. Signals of necrosis danger are produced, but not signals of consummated necrosis.
In imagined, probabilistic, speculated necrosis, no nociceptors are activated for the same reason as in the dark no photoreceptors are activated or in the silence no ear receivers are activated.
In the absence of sensory activation (light, sound waves, aromatic molecules, extreme hot and cold, stretches, mechanical compressions, insufficient oxygen quantities, pH...) the brain can activate the areas responsible for visual, sound, touch, scent, taste perception, and generate a mild and fading perceptual version. We can imagine tastes, smells, sounds, images, pain, hunger...
Usually the absence of sensory signal contains the imaginative function, it reduces it to something very subtle and inconsistent.
When we sleep, sensory inputs are disconnected. The imaginative brain processes past and future sensory data, real and fantastic, constructs impossible narratives, free ones. The brain dreams, plays with the real and the unreal. The perception becomes realistic, hallucinatory. It doesn’t need any senses. They are an obstacle.
Reality can be experienced or imagined. Senses hold the imagination but don’t always succeed at doing it.
The IASP says (International Association for the Study of Pain) that pain is an unpleasant sensory and emotional experience. I disagree. Current sensory experience is not needed. Consummated or imminent necrotic damage sensors can be mute.
"... Vision is a sensory experience ...". Not always. Sometimes we see things that are not there. There is no activation of photoreceptors, but apparently what we see is real.
- Does this mean that my brain has hallucinations, delusions of mind?
- It creates hallucinatory states of imminent necrotic damage, but not mental delusion or madness. It’s just wrong. It rates some non-existent threats as true. It doesn’t wait until necrosis occurs. It tries to prevent danger. Turn on the pain...