2014 Sensory Physiology

Stimulus Modality

Types of stimulus energy

  1. Electromagnetic and thermal energy: "visible" light, infrared, temperature, electric, magnetic

  2. Mechanical energy: sound and sonar, touch and vibration, pressure, gravity, inertia

  3. Chemical energy: tastants, odorants, humidity

 

Specificity

Critical Fact Icon(doctrine of specific nerve energies - Mueller, 1826)

Receptors:

ADEQUATE STIMULUS: the type of energy that a receptor responds to under NORMAL conditions (i.e., the type of energy that has the lowest threshold for receptor activation)

    Adequate stimulus cartoon
    The principle of specificity does NOT mean that a receptor cannot respond to other forms of energy (e.g., photoreceptors responding to intense pressure). However, due to the segregation of sensory pathways (think of the organization of sensory cortices, with each system in a different physical location), any stimulus is perceived as if it was the adequate stimulus (e.g., pressure on photoreceptors is perceived as "seeing stars").
Email: Dr. Janet Fitzakerley | ©2014 University of Minnesota Medical School Duluth | Last modified: 4-feb-14 8:26 PM