Sensation and Perception Sensation: your window to the world Perception: interpreting what comes in your window.

Sensation and Perception Sensations: Messages FROM the senses that make up raw information from outside the nervous system into neural activity Perceptions: USING the raw sensations and interpreting them

Transduction Transforming signals into neural impulses. Information goes from the senses to the thalamus, then to the various areas in the brain.

Sensory Adaptation Decreased responsiveness to stimuli due to constant stimulation. Do you feel your underwear all day?

Cocktail-party phenomenon The cocktail party effect describes the ability to focus one's listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations. Form of selective attention.

Energy v. Chemical senses Energy SensesChemical Senses

VisionVision Our most dominating sense. Visual Capture

Phase One: Gathering Light The height of a wave gives us it’s intensity (brightness). The length of the wave gives us it’s hue (color). ROY G BIV The longer the wave the more red. The shorter the wavelength the more violet.

Phase Two: Getting the light in the eye

The Blind Spot Can actually see it from outside someone's eye Light from the flash travels into the eye, gets reflected by the retina, and comes out again along the same path that it went in

The retina is covered with blood vessels and photoreceptors, it absorbs most of the light, and only reddish light comes back out Blind Spot: No photoreceptors, no light absorption, so most of the light landing on the blind spot simply gets reflected

Fovea

Fovea and Color Blindness

Function of the Fovea Accurate vision in the direction where it is pointed It comprises less than 1% of retinal size but takes up over 50% of the visual cortex in the brain

Phase Three: Transduction

Transduction Continued Order is Rods/Cones to Bipolar to Ganglion to Optic Nerve. Sends info to thalamus- area called lateral geniculate nucleus (LGN). Then sent to cerebral cortexes. Where the optic nerves cross is called the optic chiasm.

Phase Four: In the Brain Goes to the Visual Cortex located in the Occipital Lobe of the Cerebral Cortex. Feature Detectors. Parallel Processing We have specific cells that see the lines, motion, curves and other features of this turkey. These cells are called feature detectors.

Parallel Processing Allows the brain to conduct separate analysis of the same information at the same time – Color – Form – Movement

Color Vision Two Major Theories

Trichromatic Theory Three types of cones: Red Blue Green These three types of cones can make millions of combinations of colors. Does not explain afterimages or color blindness well.

Opponent-Process theory The sensory receptors come in pairs. Red/Green Yellow/Blue Black/White If one color is stimulated, the other is inhibited.

Afterimages

Hearing Our auditory sense

We hear sound WAVES The height of the wave gives us the amplitude of the sound. The frequency of the wave gives us the pitch if the sound. Sound is measured in decibels

The Ear

Transduction in the ear Sound waves hit the eardrum then anvil then hammer then stirrup then oval window. Everything is just vibrating. Then the cochlea vibrates. The cochlea is lined with mucus called basilar membrane. In basilar membrane there are hair cells. When hair cells vibrate they turn vibrations into neural impulses which are called organ of Corti. Sent then to thalamus up auditory nerve. It is all about the vibrations!!!

Pitch Theories Place Theory and Frequency Theory

Place Theory Different hairs vibrate in the cochlea when they different pitches. So some hairs vibrate when they hear high and other vibrate when they hear low pitches.

Frequency-Matching Theory All the hairs vibrate but at different speeds.

Volley Theory groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain to be analyzed.

Deafness Conduction Deafness Something goes wrong with the sound and the vibration on the way to the cochlea. You can replace the bones or get a hearing aid to help. Nerve (sensorineural) Deafness The hair cells in the cochlea get damaged. Loud noises can cause this type of deafness. NO WAY to replace the hairs. Cochlea implant is possible.

Touch Receptors located in our skin. Gate Control Theory of Pain

Taste We have bumps on our tongue called papillae. Taste buds are located on the papillae (they are actually all over the mouth). Sweet, salty, sour and bitter.

Vestibular Sense Tells us where our body is oriented in space. Our sense of balance. Located in our semicircular canals in our ears.

Kinesthetic Sense Tells us where our body parts are. Receptors located in our muscles and joints. Without the kinesthetic sense you could touch the button to make copies of your buttocks.