Stimulus Modality
Specificity
(doctrine of specific nerve energies - Mueller, 1826)
Receptors:
- respond to one form of energy more than any other
- respond to only a narrow range of stimulus energy
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)
 |
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, any stimulus is perceived as if it was the adequate stimulus (e.g., pressure on photoreceptors is perceived as "seing stars"). |
Special Senses |
"Not-so-special" Senses |
|---|---|
Audition (hearing) |
Mechanoreception (touch) includes both somatosensation and visceral sensation (e.g., blood pressure) |
Vision (sight) |
Nociception includes both somatosensation and visceral sensation |
Olfaction (smell) |
Body position (part of proprioception) |
Gustation (taste) |
Internal sensation: pH, osmolarity |
Head rotation |
|
Gravity detection |