1. How do we get sensory information from the environment to the brain?

1. Sensation p 204:

• The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

2. Bottom-up processing p 204:

• Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information

3. Transduction p 208:

• Conversion of one form of energy into another

  • The transforming of stimulus energies, such as sounds, sights, and smells into neural impulses our brain can interpret

II. When do we pick up or register a sensory experience and when do we miss it?

4. Absolute threshold p 209:

• The minimum stimulus energy needed to detect a particular stimulus 50% of the time

5. Signal Detection Theory p 209:

• A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise).

  • Assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivations, and awareness

6. Sensory adaptation p 211

• Diminished sensitivity as a consequence of constant stimulation

  • When exposed to an unchanging stimulus, we became less aware of it because nerve cells fire less frequently

III. When do we notice when the stimuli are getting stronger or weaker?

7. Just-noticeable difference (or difference threshold) p 209:

• AKA difference threshold

  • The minimum difference between two stimuli required for detection 50 perent of the time

  • Just a noticeable difference

  • Detects differences in stimuli

8. Weber’s law p 211 & https://www.alleydog.com/glossary/definition.php?term=Webers+Law#:~:text=Weber's%20Law%20is%20related%20to,50%20percent%20of%20the%20time.: 

• To be perceived as different, two stimuli must differ by a minimum percentage, rather than a constant amount

  • Percentage depends on stimulus

IV. How do the senses interact to help perceive our complex environment? 

9.  Sensory interaction (use link): https://www.alleydog.com/glossary/definition.php?term=Sensory+Interaction#:~:text=Sensory%20interaction%20refers%20to%20the,others%20if%20information%20seems%20contradictory.

• The interaction of the senses with one another and how they influence each other 

  • Ex: taste and smell work together

  • Some senses can overrule others if information is contradictory

10. Synesthesia (not a disorder but a unique interaction of sensory information) https://www.alleydog.com/glossary/definition.php?term=Synesthesia:

• Hi I actually have this you do not need to tell me what synesthesia is 

• The stimulation of one sense results in other senses being activated

• For me, sounds are perceived as color

• Not much is known about the causes of synesthesia - might be hereditary

  • Except it’s not for me, because no one else in my family has it

• Can be acquired through brain injury, but most people have it for their entire lives

VISION: mod 22 from pages 222-232 (review answers: 1. A  2. D   3. B   4. B   5. C)   

V. How does the eye transduce light energy into what the brain can understand (neural language)?

11. Retina p 223 and Fovea p 225

• Retina

  • The light-sensitive inner surface of the eye

  • Contains receptor rods and cones plus layers of neurons that begin the processing of visual information

• Fovea

  • The central focal point on the retina

  • Eye’s cones cluster

  • Towards back of eye

12. Photoreceptors: p 224

• Cells that convert light energy into neural impulses and forward those to the brain which reassembles them into an upright seeming image

• Rods and cones are photoreceptors

13. Rods vs Cones (blue, green, red): p 224

• Rods

  • Retinal receptors that detect black, white, and gray

  • Sensitive to movement

  • Necessary for peripheral and twilight vision, when cones don’t respond

• Cones

  • Retinal receptors that are concentrated near the center of the retina

  • Function in daylight or well lit conditions

  • Detect fine detail and give rise to color sensations

14. Ganglion cells (become the visual or optic nerve): p 224

• Activated by bipolar cells

• Axons come together to form the optic nerve

VI. How do visual blindspots happen?

15. Blindspot: p 225

• The point at which the optic nerve leaves the eyes

  • Creates a blindspot because no receptor cells are located there 

16. Optic or visual nerve: p 224

• The nerve that carries neural impulses from the eye to the brain

VII. How does our eye adjust for distance and what happens when this process  isn’t working properly:

17. Lens p 223

• The transparent structure behind the pupil that changes shape to help focus images on the retina

18. Accommodation: p 223

• The process by which the eye’s lens changes shape to cous near or far objects on the retina

19. Nearsightedness: ttps://medlineplus.gov/ency/imagepages/19511.htm#:~:text=A%20nearsighted%20person%20sees%20near,focusing%20power%20being%20too%20weak.

• Blurred vision when visual images are focused in front of the retina, rather than directly on it

  • Physical length of eye is greater than the optic length

  • Seeing near objects clearly

20. Farsightedness

• The result of visual imaging being focused behind the retina

• Caused by eyeball being too much or focusing power being too weak

• Seeing faraway objects clearly

VIII. How do we see color and why can’t everyone see the same colors?

21. Wavelength (electromagnetic spectrum): p. 222 & p 223 

• The distance from the peak of one light or sound wave to the peak of the next

• Varies from gamma rays (short) to radio transmission (long)

• Wavelengths

  • Short - high frequency, bluish colors

  • Long - low frequency, reddish colors

• Amplitudes

  • Great - bright colors

  • Small - dull colors

22. Trichromatic theory: p 227

• The retina contains three different types of color receptors - one most sensitive to blue, one to green, and one to ed

  • When stimulated in a combination, can production perception of color

23. Opponent-process theory: p 228

• Opposing retinal process (red-green, blue-yellow, white-black) enable color vision

  • Ex: some cells are stimulated by green and inhibited by red, others are opposite

24. Afterimages: image 22.9 on page 228 and https://www.alleydog.com/glossary/definition.php?term=Afterimage

• Occurs when visually perceiving an image after you are not looking at the stimulus anymore

• Negative afterimage occurs after staring at a colored stimulus

• Positive afterimages occur less frequently and are short

  • Stimulus must be very bright

25. Dichromatism: https://pilestone.com/blogs/news/different-types-of-color-blindness

• A person cannot see a certain set of two colors

  • Usually red/green or yellow/blue

  • Explained by Opponent Process Theory

26. Monochromatism:

• A person cannot see any color and only sees the world in black and white

IX. Can your eyes be functional without being able to “see”? 

27. Prosopagnosia:p 203-204 or  https://www.alleydog.com/glossary/definition.php?term=Prosopagnosia+%28Face+Blindness%29

• Face blindness

• People are unable to recognize faces

• Can see individual body parts but not an entire face as a whole

• Cannot commit faces to memory - not even their own face

• Everyone looks the same - makes it trouble to connect emotionally to others

• Can be from a brain injury or inherited

28. Blindsight: p 125 & 230

• A person can respond to a visual stimulus without consciously experiencing it

• Being able to complete activities as if you can see but in reality, you are blind