The awareness of changes in the internal & external environment
What is perception?
The conscious interpretation of sensation stimuli
Somatosensory System organization
* Input comes from: exteroceptors, proprioceptors, & interoceptors * Three main levels of neural integration: receptor level, circuit level, & perceptual level
Receptor level processing
* The sensory receptors * Must have specificity for the stimulus energy * The receptor's receptive field must be stimulated * Stimulus energy must be converted to a grated potential * Generator potential in sensory neuron must reach threshold
Sensory receptor adaptation
* Occurs when sensory receptors are subjected to unchanging stimulus * Receptor membrane becomes less responsive * Receptor potentials decline in frequency or stop
Which sensory receptors adapt quickly?
The receptors that respond to pressure, touch, & smell
Which sensory receptors adapt slowly?
The receptors resonding to Merkel's discs, Ruffini's corpuscles, & interoceptors that respond to chemical blood changes
Which sensory receptors do NOT adapt?
The receptors responding to pain & proprioceptors
* Soma reside in dorsal root or cranial ganglia * Conduct impulses from the skin to the spinal cord or brain stem
* Somas reside in dorsal horn of spinal cord or medullary nuclei * Transmit impulses to thalamus or cerebellum
* Located in thalamus * Conduct impulses to the somatosensory cortex of the cerebrum
How occurs at the perceptual level
Thalamus projects fibers to the somatosensory cortex & sensory association areas
Detecting a stimulus has occurred & requires summation
How much of a stimulus is acting
Identifying the site or pattern of the stimulus
Used to identify a substance that has specific texture or shape
Ability to identify submodalities of a sensation (like sweet or sour)
Ability to recognize patterns in stimuli (like a melody or a familiar face)