Explain how sensory coding and processing allow the central nervous system to communicate information on the four properties of a stimulus.

Question

What will be an ideal response?

Answer 1

The four properties of a stimulus are modality, location, intensity, and duration. Modality, or nature of the stimulus, is indicated by which neurons are activated and where their associated sensory pathways terminate. As each receptor type has an adequate stimulus and labeled line coding ensures that whenever that receptor is activated, the adequate stimulus will be perceived independent of what activated the sensory receptor associated with a particular region of the body. The cerebrum and other brain areas are highly organized into topographic maps of the receptive fields of their sensory receptors, ensuring that location of a stimulus is accurately detected. The number of receptors activated and the frequency of action potentials along the sensory pathway both increase as stimulus intensity is increased. The information on duration depends upon the adaptive properties of the receptor: tonic provide continuous information on a particular parameter whereas phasic provide information that a parameter has changed.