1. Sensory Systems
Lecture 12

2. Sensory Information Detection of changes in environment
external or internal
4 main functions
perception
control of movement
regulation of body function
maintenance of arousal
Not all conscious experience ~

3. Sensation vs. Perception
detection of stimulus
1st interaction with NS
filtering
Perception
integrated of information
selected, organized & interpreted
Different perceptions of same event ~

4. Sensory Receptors Specialized cells similar properties to neurons
Transduction
environmental energy  neural signal
receptor potential ~

5. Sensory Receptors Mechanoreceptors auditory, somatosensory
Chemoreceptors
taste, smell
Photoreceptors
vision
Thermoceptors
hot, cold ~

6. Sensory Information: 4 types
Modality
visual vs. pain vs. auditory, etc.
Doctrine of specific nerve energies
Intensity
frequency code
Duration
fast & slow adapting receptors
Location
receptive fields ~

7. Cortical Organization
Topographic
area in receptive field
mapped onto cortex
Examples
cochlea  A1
retina  V1
dermatomes  S1 ~

8. Organization of Pathways
Hierarchical (serial)
receptor  1st order neuron  higher order neuron
levels: different processing function
Parallel (simultaneous)
different submodalities
color vs. monochrome vision
pain vs. touch
converge at higher cortical levels ~

9. Sensory Modalities
Auditory
timbre
pitch
Vision
color
shape
motion ~

10. Sensory Modalities Chemical senses Gustatory – taste Olfactory - smell
Orienting senses
vestibular system
head orientation, rotation, balance
mechanoreceptors in middle ear ~

11. Sensory Modalities: Somatosensation
Primarily mechanoreceptors
Touch
pressure, vibration
Kinesthesis
body position & movement ~

12. Sensory Modalities: Somatosensation
Pain (stretch receptors)
itch (chemoreceptors)
temperature (thermoreceptors)
Haptic System
touch & kinethesis