Central Nervous System
True about weber Fechner law? (AIIMS NOV 2008)
|A||It states that localization of two pts depends on the magnitude of the stimulus.|
|B||Intensity of stimulus is proportional to sensational feel.|
|C||Dorsal columns are sensory and ventral columns are mortal|
|D||Stimulus of sensation is directly proportional to stimulus applied.|
I. Low of projection states that, no matter where a particular sensory pathway is stimulated along its course to the cortex, the conscious sensation produced is referred to the location of the receptor.
II. Phantom limb is a phenomenon seen in amputees. The patient complains of pain and proprioceptive sensation sin the absent limb. This is because, the ends of the nerves cut at the time of amputation, are stimulated by pressure on them or may even spontaneously. The impulse generated in these nerve fibers previously came from sense organs in the amputated limb, thus the sensations felt are projected to where the receptors used to be.
III. Bell Magendie Law
IV. States that in the spinal cord, the dorsal roots are sensory and the ventral roots are motor.
V. Weber Fechner and the Power law both principles are used to explain one’s Judgment of sensory stimulus intensity.
VI. Weber Fechner low
VII. It states that gradations of stimulus strength are discriminated approximately in proportions to the logarithm of stimulus strength.
VIII. Power Law
IX. States that a person interprets changes in intensity of sensory stimuli approximately in proportion to a power function of the actual intensity.
X. Its given by formula.
Interpreted signal strength = K x (stimulus – K) y
(In this formula the exponent y and the constant K and k are different for each type sensation)