Sensory Integration

General senses

touch, pressure, temperature, itch, pain

• found in throughout the body

Special senses

vision, hearing, equilibrium, smell, taste

• Located in specialized sensory organs

Sensation

awareness of stimuli

Perception

interpretation of stimuli

Complex “thinking” occurs in the

cortex where sensory information is processed and interpreted

Somatosensory cortex processes

general senses (ex: touch, temp, pain)

Special senses go to their

specific brain region

Three levels of sensory integration:

1. Receptor level

2. Circuit level

3. Perceptual level

Receptors level

detects stimuli and converts it into electrical signals

Circuit level

route signals through the nervous system, often filtering and modifying them

Perceptual level

Brain interprets signals and determines a response

Adaptation

when a sensory receptor stops responding to a constant stimulus over time

• Ex: you stop feeling your clothes after wearing them for a while

Adaptations can happen at any

three levels involved in sensory integration

Receptor level adaptation

Happens at the site of detection (sensory receptors)

• If stimulus is constant, receptors reduce their response over time

• Ex: Too much light = transducin moves away, stopping phototransduction

Circuit level adaptation

Neural pathways filter or modify sensory signals before they reach the brain

• Some signals are dampened or ignored to prevent sensory overload

• Ex: Reticular formation filters out background noise

Perceptual level adaptation

happens in the cortex

• brain learns to tolerate or ignore certain stimulu over time

• Ex: Pain tolerence can be trained. If you focus on something else, the brain reduces pain perception

Reticular formation

filters out unimportant sensory input to prevent overload

• function: alertness + filter sensory info

Reticular formation is located in the

brain stem and filters incoming sensory information before it reaches the cortex

If the reticular formation is damaged a person may

lose consciousness or enter a coma due to lack of sensory processing

Phasic receptors

adapt quickly

• help us focus on changes in environment

• (Ex: light, touch, smell)

Tonic receptors

adapt slowly or not at all

• stay away of crucial information like pain or balance

Why are pain receptors tonic?

Pain is essential for survival, if they adapted quickly we wouldn’t notice injuries leading to further damage