Question

How is sensory information coded? That is, how can your CNS distinguish the type of stimulus, the location of the stimulus, and the intensity of the stimulus?

Answer 1

Coding in sensory systems means

• the way the energy of the stimulus is transformed to changes in nerve
• membrane potential.
• the way information about the stimulus is conveyed to sensory centers.
• the control of a sense organ's output by coded signals from the central
• nervous system.
• the system by which sense organs are protected from adaptation.

CNS Detection of a stimulus is called sensitivity and receptors are responsible for Sensitivity where receptors are typically neurons or cells that are able to sense changes in the environment.

Some of the receptors are

• Chemoreceptors
• Photoreceptors
• Mechanoreceptors
• Thermoreceptors
• Nociceptors

Location of Stimulus

There are 5 types of stimuli that can be perceived by the skin: Touch, pressure, pain, temperature, and vibration.

Acuity is the ability to localize a stimulus. It is determined by receptive field size and receptor density. There is an inherent paradox between the intensity of a stimulusand the ability to localize it.

In sensory neurons, stimulus intensity is coded by

• Absolutely labeled lines for each intensity.
• Topographical organization.
• Across fiber patterning.
• Variations in spike frequency.