Sensory Systems

Lesson 14

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 ~

Sensation vs. Perception Sensation

detection of stimulus 1st interaction with NS filtering

Perception integrated of information selected, organized & interpreted

Different perceptions of same event ~

Sensory Receptors

Specialized cells similar properties to neurons

Transduction environmental energy neural

signal receptor potential ~

Sensory Receptors Mechanoreceptors

auditory, somatosensory Chemoreceptors

taste, smell Photoreceptors

vision Thermoceptors

hot, cold ~

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 ~

Cortical Organization

Topographic area in receptive field mapped onto cortex

Examples cochlea A1 retina V1 dermatomes S1 ~

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 ~

Sensory Modalities

Auditory timbre pitch

Vision color shape motion ~

Sensory Modalities

Chemical senses Gustatory – taste Olfactory - smell

Orienting senses vestibular system head orientation, rotation, balance mechanoreceptors in middle ear ~

Sensory Modalities: Somatosensation

Primarily mechanoreceptors Touch

pressure, vibration Kinesthesis

body position & movement ~

Sensory Modalities: Somatosensation

Pain (stretch receptors) itch (chemoreceptors) temperature (thermoreceptors)

Haptic System touch & kinethesis