What is the absolute threshold in neuroscience?
People's nervous systems process sensory information by interpreting external and internal stimuli and transferring information to the brain for processing. Neurons in the brain receive electrochemical impulses. Like any type of sensory tool, different afferent or receptor, neurons have a minimum stimulus that can actually detect. This stimulus, called the absolute threshold, varies between people and can be influenced by external conditions. When individuals are tested, they may or may not experience a stimulus; Therefore, the absolute threshold is defined as the lowest detectable level of 50% of the time.
Vision relies on two types of cells, rods and cones that have different functions. Cones detect color; Rods detect shapes and are best suited for seeing in the dark. The absolute threshold for vision or the minimum number of photons that the eye can detect is generally accepted as 90 photons, of which only nine reaches retina and on foot, the most sensitive part of the eye. This measurement assumes OPTimal conditions; ie eyes completely groomed to darkness and wavelength, on which the cells of the rod are the most sensitive.
Hearing work transmits electrochemical impulses through the auditory nerve as air vibrations transmit from the ear drum to the cilia in the inner ear. The minimum atmospheric pressure that causes sound sound when the source adjacent to the ear is 20 micropascals, provided no hearing damage. The ear aims to hear sounds of 20 to 20,000 Hertz, but it is most sensitive when it is exposed to frequencies between 1,000 and 5,000 hertz.
Several factors can affect the reported absolute threshold of man: the expectations or expectations of the stimulus, repeated exposure, damage to the sensory organs and mental or emotional state. If a person expects to receive a specific stimulus, he or she will naturally be more attuned. Repeated exposure, on the other hand, causes the sensory nervous system to filter this typeinput. Damage to the sensory organs increases the absolute threshold value and the high level of stress causes the body to secrete adrenaline, which increases the sensory organs tuned to incoming stimuli and probably react.
Absolute threshold value differs from the sill value of the difference. This measurement concerns the minimum difference between two or more stimuli needed to detect any difference. The threshold value of the body can be trained; For example, wine tasters learn to distinguish between almost identical flavors of wine.