Sensory System. Sensory channels Discriminative: spatial and temporal localization of events Affective: pain and positive emotional experiences monitoring.

Sensory System

Sensory channels

• Discriminative: spatial and temporal localization of events

• Affective: pain and positive emotional experiences

monitoring internal and external environment

Multisensory Experiences

• Interconnecting networks• Most information as quickly as possible• Must integrate that information

• Experiment 1: flavors of liquid• Experiment 2: jellybean flavors

Experiment 1• Observe the liquids, record your hypotheses in the table. • Place a cut straw into cup A.

• Put a finger on the exposed end of the straw, trapping liquid in the straw.

• Open your mouth, placing the straw over your tongue, and release your finger from the top of the straw. Do not allow the straw to touch your tongue.

• Taste the solution and write down the flavor in the table.

• Use a different straw for each solution, repeating the same procedure for each liquid.

Experiment 2

• Obtain a jelly bean• Record your hypothesis about the flavor• Hold your nose, eat the bean. Record taste.• Release your nose, what do you taste now?

Receptors

• Specialized area of a sensory neuron that detects a specific stimulus.

5 types:

• Chemoreceptors• Thermoreceptors• Mechanoreceptors• Photoreceptors• Nocioceptors

Stimulus

5 types:

• Chemoreceptors: changes in chemical concentrations

• Thermoreceptors: changes in temperatures• Mechanoreceptors: changes in pressure or

movements of body fluids• Photoreceptors: light energy• Nocioceptors: tissue damage or distension

associated sense(s)…

Experiment 3

• Peppermints• Sour patch kids

• Hold nose, eat, record flavor

Sensation

• Conscious awareness of incoming sensory information

Perceiving a Sensation

• Stimulus receptor sensory nerve special area of brain

Aristotle Illusion: Experiment 4

• Cross your middle finger over your index finger.• Place a marble on the table top and place the

pads of your crossed fingers on top of the marble.

• Look away from your hands, and then slightly roll the marble back and forth in the crevice of your crossed fingers.

• Record your findings and answer questions.

Experiment 5: wooden dowel tapping

• Follow instructions as given

Aristotle’s Illusion

• Usually fingers aren’t crossed when manipulating objects

• Brain doesn’t account for it – felt two marbles

Dowel Rods

• Sense of touch not altered – perception was• Harder to tell which was tapped first when

crossed arms• Both crossed (arms and dowel rods) – easier

to tell which one was tapped first.

Both activities

• Illustrate a limitation to PERCEPTION of sense of touch.

• you are “hardwired” for “normal” operating circumstances

Experiment 6: vinegar

• Follow procedure as given

Adaptation

• If a receptor is continuously stimulated, sends fewer signals to the brain.

• Why would this be advantageous? • Receptors vary in ability to adapt: – Pressure and touch: rapid– Nocio- not at all– Body position and blood chemistry – slow

Projection

• Process by which the brain, after receiving a sensation, refers that sensation back to its source.

pain

General Senses

• Pain• Touch and pressure• Temperature• Proprioception

Pain: main triggers

• Tissue injury – releases particular chemicals• Oxygen deficiency – heart attack and admin of

oxygen• Stretching or deformity of tissue – mechanical

rather than chemical (bloating/distention)

Referred pain – shared sensory pathways

Pain medications – how do they work?

Touch and Pressure

• Tactile receptors• Mostly on skin• First sense to develop in utero• Essential to growth and development

Kangaroo care

• Skin to skin contact from early on• Warmth and physical contact• Causes neurobiological changes:– Calming– Stabilizing temperature– Improve feeding Failure to thrive

Temperature

• Scattered widely throughout body, many in skin

• Cold: 10oC – 25oC (50oF – 76oF)• Heat: 25oC – 45oC (76oF – 112oF)• Pain receptors stimulated on either end of

scale• Adapt quickly

People from Phoenix…versus people from Chicago…

Experiment 7

• Cooling effect of menthol?– Halls (or any cough drop with menthol)– Drink a hot beverage – do you know its hot?

Proprioception

• Sense of orientation/position• Knowing where your body is in space• Can locate a body part without looking at it• Essential role in maintaining posture and

coordinating body movement

proprioreceptors

• Located in muscles, tendons, and joints• Also in inner ear (for equilibrium)• Cerebellum receives messages (coordinating

skeletal muscle activity).• Movement and position info sent to parietal

lobe of the cerebrum

Finding Fingertips

• Close your eyes and raise both hands above your head

• Keep the fingers of your left hand completely still• With your right hand, quickly touch your index finger

to your nose, then quickly touch the tip of your thumb of your left hand (with your right index finger).

• Quickly repeat the entire process attempting to touch each fingertip.

• Switch hands and try again.

“X” marks the spot

• Mark an X on a piece of paper.• Pencil in hand, raise your hand above your

head, close your eyes, and make a dot as near as possible to the X.

• Open your eyes and check your success. • Repeat several times. • Try it with the other hand.

Handwriting Analysis

• Lined sheet of paper, write proprioception. • Place your pencil on the same line next to the

written word, close your eyes, and write proprioception again.

• You can try it again and see if you improve.• You can try it again with your nondominant

hand.

Special Senses

• Smell: olfactory cortex• Taste: gustatory cortex• Sight: visual cortex• Hearing: auditory cortex• Balance: cerbellum