Untitled Flashcards Set

Sensation (bottom-up): binocular disparity

• When an object is closer, our eyes point more sharply inward

• Our brain automatically processes this angle and uses it to process depth perception

• This is why people lose some of their depth perception when they lose function in one eye

Top-down processing makes it a bit easier (cues)

• Monocular cues: parallel lines converge in distance, smaller objects = farther away, interposition (objects blocking others = closer)

• Provide shortcuts for us to perceive and navigate the environment… prone to illusions

Ponzo Illusion (train tracks… further away, one looks bigger)

Muller-Lyer Illusion

• The “outie” one looks like a farther, interior corner

• The “innie” one looks like a closer, exterior corner

• Would not work on people who comes from backgrounds with different architectural styles (people who are raised in cultures without carpentry or architecture)

The Hermann Grid

• Lateral inhibition: nearby neurons suppress each other’s activity to enhance contrast

  • When you focus on a white dot, nearby white/brightness neurons are suppressed to enhance contrast (creating false perception of gray dots)

The McGurk Effect

• Multisensory Integration: when your brain integrates conflicting signals, you perceive a cross between two signals

  • Hearing “ba” + seeing “fa” = “da”

• Synchresis: the brain’s automatic fusion of sound and sight (we’re wired to see synchronicity between sound and sight)

  • The random video will seem like it fits the music

The Double-Flash Illusion

• Crossmodal perception

• Brain expects synchronicity between sight and sound

• Your brain perceives a second beep to match the (more ambiguous) sight to the (clearer) sound

Rubber Hand Illusion (brain prioritizes visual input, you start to “feel” the fake hand)

• Multisensory integration

• Mirror-Box Therapy uses multisensory integration to solve amputee patients’ excruciating phantom-limb pain

Common Causes of Vision Impairment

Cataracts: clouding of the lens, making vision blurry

• Causes: aging, UV-light exposure, smoking diabetes, steroid use

• Surgery is among the most common; replaced with artificial lens

Glaucoma: damage to optic nerve due to increased pressure

• NO early symptoms

Macular Degeneration: foveal damage → loss of central vision (macula = fovea)

• Peripheral vision remains intact… reading and recognizing faces becomes difficult

• Causes by oxidative stress, eating antioxidants (spinach, kale) helps protect vision

Diabetic Retinopathy: blood vessel damage in the retina

• Affects people with uncontrolled diabetes; highest cause of vision loss amongst working-age adults

Common Ways to Lose Hearing

Noise-Induced Hearing Loss: hair cells in the cochlea die

• People who use headphones at/near max volume (especially earbuds)

Tinnitus (product of INHL): a persistent ringing in the ears

• Like phantom-limb pain, but for hearing

• Above 85 db, it is mandatory to wear hearing protection (over 8 hours)

Presbycusis: age-related hearing loss

• Most people over 60 experience it

* Hearing loss is a major risk factor for cognitive decline

• Reduced auditory input leads to… brain shrinkage

• Hearing loss leads to… social withdrawal (and that leads to dementia)

Class IDK: 2/13/25

Sugar

• Evolutionary Mismatch

The Current Sugar and Obesity Epidemic

• Since 1975… obesity rates have tripled, and sugar consumption has also tripled

How much should we eat?

• Fewer than 25g/day for women

• Fewer than 36g/day for men

• Average American consumes between 52-129 g of sugar PER DAY

How does sugar affect the body? - obesity, heart disease, diabetes, tooth decay, liver disease, joint pain, death

Recreational Drugs: for most of evolutionary history, humans did not have access to drugs

• Our resting brain chemistry is thrown off when using recreational drugs

• Associated with… impulsivity, poor self-regulation, low resting level of dopamine

Refined Sugar: acts like recreational drugs

• Our resting brain chemistry is thrown off when using refined sugar

• Associated with… the exact same things as recreational drugs

• Refined sugar strongly activates the reward pathway in the brain… the same pathway that is associated with addiction and drug use

Parallel between sugar and drugs

• “Replace their drug addiction with another addiction”

  • Drug addicts’ brains show increased sensitization to their drug of choice… causes abnormally high dopamine spikes (compared to non-addicts)

  • Cross-sensitization: once you become addicted to something, you’re more likely to pick up other addictions

Excessive sugar consumption leads to… memory impairment, degeneration of hippocampus

This highlights the importance of addressing underlying issues and finding healthier coping mechanisms to prevent the cycle of addiction from continuing.