Introduction to Sensation: EQ: How do our sensory systems function and how do they allow us to interact with the world around us?

I. What is a Sense? A sense is a biological system that translates information from outside the nervous system into neural activity These sensations (raw information from the senses) go to the brain where they are perceived These sensations and perceptions dictate many aspects of our behavior

What to do???

II. Sensory Systems: How it Works!!! (Copy Me) Energy Contains information about our world. Accessory structure modifies energy. Receptor transduces energy into a neural response Sensory nerves transfer the coded activity to the central nervous system Thalamus processes and relays neural response. Cerebral Cortex receives input and produces the sensation and perception

A. Accessory Structures: Accessory Structures are specifically designed to modify stimulus EX: The Pinnae of the ear. EX: The Lens of one’s eye

B. Transduction: Once the stimulus has been accessed, it needs to be transduced. During this process, the energy from the accessory structures is changed from incoming energy into neural activity in the receptor organs This is a very complicated process that involves coding (Discussed Later)

Transduction in Action!!!

C. Sensory Nerves: The sensory nerves are designed to specifically to carry the coded messages created in transduction to the central nervous system This neural impulse will be carried into the brain

D. The Thalamus: The Thalamus works like a central processing system and re- directs the coded message to the correct part of the brain -Hearing: Temporal Lobe -Vision: Occipital Lobe -Olfaction (Smell): Frontal Lobe -Gustation (Taste):Parietal Lobe -Touch: Parietal Lobe

E. The Cerebral Cortex: Once the coded message reaches the correct part of the brain, we become aware of the sensation and perception of the stimulus. Without our brain, we would not be able to decode the message.

F. Behavior: Our behavior is determined by many variables. In the case of sensation, our behavior will generally be based on a pre-programmed response to certain types of stimuli EX: Loud Scream EX: Smelling a fart EX: Bright Light

III. Coding in Transduction Imagine you are trying to describe a sunset to a person who has always been blind. Now imagine trying to describe what a song sounds like to a person who cannot hear. In these examples, the difficulty is that these people have no experience with which to understand what you are trying to say. They may understand to some extent, but they cannot fully appreciate it like you can This is similar to coding

III. Coding in Transduction Coding (translating the physical properties of a stimulus into a pattern of neural activity that specifically identifies those properties) is what allows the information from our senses to be carried to the brain. Without coding, or if we had coding errors, we would not be able to understand the stimuli in the world around us.

A. Doctrine of Specific Nerve Energies Doctrine of Specific Nerve Energies: The discovery that the stimulation of a specific sensory nerve provides codes for that sense, no matter how it is stimulated. In other words, If I want to see the that Pagani, I must stimulate my optic nerve. If I want to smell it…

B. Types of Coding Temporal Codes: Coding attributes of a stimulus in terms of changes in the timing of neural firing EX: Lightning will impact your vision differently than a gradual increase in light Spatial Codes: Coding attributes of a stimulus in terms of the location of firing neurons compared to their neighbors EX: A girl in a bar grabs your Hiney. You will feel it in your hiney, not your foot.