He lived 1795 to 1878, studied psychophysics, invented theory of signs {Lokalzeichentheorie}, measured skin sensitivity to separated stimuli [1826], studied inhibition by vagus nerve [1845], and developed law of sensation [1834], with Fechner. People can distinguish between two similar sensations {just-noticeable difference}. For each sense, ratio of just-noticeable-difference to intensity is approximately constant for all intensities. Subjective sensation increases as logarithm of physical-stimulus magnitude. Just-noticeable difference increases in direct proportion to stimulus intensity. If I is sensation intensity, intensity change divided by intensity equals constant {Weber-Fechner law} {Weber's law}: (I2 - I1) / I1 = Weber's constant. Weber's constant {Weber fraction} represents smallest stimulus intensity difference that people can perceive. If intensity is higher, differences must be larger for people to perceive them. Weber's constant is typically greater than one to three percent, differs for different senses, and tends to increase with age.
He lived 1755 to 1826.
He lived 1837 to 1900 and found rhodopsin retinal pigment {visual purple} in rod photoreceptors for twilight vision [1877].
He lived 1834 to 1918. Lung receptors signal distension, stop inspiration {Hering-Breuer reflex}, and partly control respiration.
He explained brightness perception, color vision, afterimages, and complementary colors by starting from neutral point and moving in anabolic or catabolic direction {opponent color theory, Hering}. Yellow does not subjectively appear to mix green and red and is stable over intensity changes, so yellow is a primary-color complement. Eye-movement, color-detection, and brightness-detection mechanisms are inborn. People see unique blue, unique green, and unique yellow, because they affect all three cones and, at that wavelength, people perceive no other color mixed in. People do not see unique red, because only two cones affect red.
Brain substance can contain memories, and memory is a material process, because memory survives unconsciousness and sleep.
He lived 1823 to 1915 and studied insect behavior and sense capacities.
He lived 1852 to 1932 and studied pain and touch sensations.
He lived 1886 to 1983. Fish can have color vision and can hear. Special honeybees {scout honeybee} convey information about food-source direction and distance by performing symbolic dances after they return to hive floor. Bee determines direction in reference to Sun or to sky light-polarization angle, detectable by bee compound eye. Dances have a symmetry line, which indicates food-source direction. Dance kinds and speeds indicate food-source distance: slow and round for near and fast, and waggly for far.
He lived 1928 to ?. Living cells rebuild themselves {autopoiesis, Maturana}.
He lived 1924 to ? and studied visual-cortex organization, with David Hubel. Not using eye during critical or sensitive period to detect stimulus feature makes visual cortex unable to detect stimulus feature {sensory deprivation, Wiesel}.
He lived 1926 to ? and studied visual-cortex organization, with Torsten Wiesel. Not using eye during critical or sensitive period to detect stimulus features makes visual cortex unable to detect stimulus features.
Brain detects color in round vertical columns, located 0.5 mm apart in regular arrays between primary-visual-cortex orientation columns, using double-opponent neurons, with both ON-center and OFF-center circular fields, to compare colors. He found blobs by staining primary visual cortex with cytochrome oxidase (CO), with Margaret Livingstone. Interblob regions detect orientation.
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He lived 1956 to ?. Neural activity differs in dreaming, awake, or brain-damaged {activity principle, Koch}. Different animal types can have different neural-activity patterns. Perhaps, some neuron set has same ion channels, shape, receptors, axons, or biochemistry {neuronal correlates of consciousness, Koch}.
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Date Modified: 2022.0225