1. Introduction to Sensation
The Basics

3. Streams of info coming in from different senses interact.
Translation of info from outside the nervous system into neural activity.
Streams of info coming in from different senses interact.
Reality of sensation differs from person to person.

4. Which do you prefer?
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5. Sensory Interaction
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6. What is this image? Don’t take the sensory process for granted!
Your visual system had to detect the light reflected off the screen and translate (or transduce) the light energy into neural activity the brain could interpret.
Your brain doesn’t interpret raw physical energy.
Our sensory systems are so efficient we are rarely aware of the process.

7. Sensation & Perception
The process through which the senses are given meaning
Sensation
Info about the world is gathered from forms of energy
Sound, light, heat, physical pressure.

8. Sensory Systems
Auditory/Visual/Gustatory/Olfactory/Tactile/Proprioceptive Systems
Humans rely primarily on vision/hearing/skin sensations to gather info about the world
Humans rely less on smell & taste to gather info about the world

9. Sensory System Process
Energy contains info about the world
Accessory structure modifies energy
Receptor cells transduces energy into a neural response
Sensory nerves transfer coded activity to the CNS
Thalamus processes and relays the neural response
Cerebral cortex receives input and produces the sensation & perception
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10. Example Accessory Structures
Lens of the Eye
Pinna of the Ear
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11. Receptor Cells in the Sensory Systems
Respond to changes in energy
Constant levels of stimulation result in adaptation
Transduction is the process of converting incoming energy into neural activity.
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12. Examples of Sensory Adaptation
Visual dark adaptation
Turning off the lights
Smell (good or bad) adaptation
Walking into someone’s house
Temperature (not too extreme) adaptation
Adjusting to the temperature outside
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13. Coding of Sensory Information
Coding is the process of translating the physical properties of a stimulus into a pattern of neural activity that specifically identifies those properties.
Think about action potential.

14. Types of Sensory Coding
Temporal Coding
TIMING patterns of a nerve firing.
The more INTENSE the energy, the faster the neuron fires
Spatial Coding
Involves the location of firing neurons relative to their neighbors.
Allows us to know where sensations are coming from.

15. Doctrine of Specific Nerve Energies
Stimulation of a particular sensory nerve codes for that sense no matter HOW the stimulation takes place
1. With your eyes closed, press on your eyeball…gently!
2. Ever get hit by something on the ear/side of your head?
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