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Retinal disparity

Binocular cue

• eyes view things differently due to 2.5 inches apart

Convergence

Binocular cue

• things far away, eyes are relaxed

• tings close to use, eyes contract

Weber’s law definition

Made the term “just noticeable difference”

• threshold at which you will feel a change in any sensation

Weber’s law equation

ΔI / I = K

• ΔI is the JND, I is the original stimulus intensity, and K is a constant specific to the sensory modality (like weight, sound, or light)

Absolute threshold of sensation

Minimum intensity of stimulus needed to detect a particular stimulus 50% of the time

Signal detection theory

How we make a decision under conditions of uncertainty—discerning between important stimuli and unimportant “noise”

Strength of a signal using d’ and c

d’: hit>miss (strong), miss>hit (weak)

• Big d’ is strong signal

c: conservative (no unless 100% signal is present), or liberal (always say yes, even if false alarms)

Bottom-up processing

Stimulus influences our perception

• Processing sensory information

Top-down processing

Background knowledge influences perception

• Driven by cognition

Similarity

items similar to each other are grouped together

Pragnanz

reality is organized and reduced to the simplest form possible (ex. 5 circles become olympic rings)

Proximity

objects that are close are grouped together

Continuity

lines are seen as following the smoothest path

Closure

objects grouped together are seen as a whole

What are rods? How many do we have?

Night vision (found in the periphery)

• 120M

What are cones? How many do we have?

Color vision: red, green, blue (centered in fovea)

• 6-7M

What is the mechanism in rods vs. cones

Both:

• Phototransduction cascade initiates if light hits rhodopsin

Rods: 1000x more sensitive, but slow recovery time

Cones: fast recovery time

Parallel processing

Using multiple pathways to process incoming stimuli that differs in quality

What is the function of the cribriform plate?

Separate olfactory epithelium from the brain, creating a space for the olfactory bulb, a bundle of nerves with specific receptors at each end.

Mechanism for smell

Molecule binds receptor → Glomerulus → Synapses with Mitral/Tufted cell → Brain → GPCR → AP

Pheremone

Chemical signal that induces innate response that leads to mating, fighting, and communication

Vomeronasal system

Basal and apical cells have receptors

• Basal cell sends signal to amygdala

What is the two different types of gustation mechanisms?

GPCR, G protein dissociates, ion channel, cell depolarize and AP

• Sweet, umami, bitter

Binds directly to ion channel → AP

• Sour (H⁺), salty (Na⁺)

What is the sequence for stages of sleep?

N1 → N2 → N3 → N2 → REM

Describe the first stage of sleep:

N1:

• Theta waves are dominant

• Hypnic Jerks

• Tetris effect

• Hypnagonic hallucinations

Describe the Tetris effect

If you play tetris before bed, you might see blocks

• Characteristic of N1 Sleep

Describe the second stage of sleep:

N2:

• People are harder to awaken

• MORE Theta waves present

• Sleep spindles

• K-complexes

What is the purpose of sleep spindles?

To inhibit certain perceptions to maintain a tranquil state during sleep allowing us to sleep through loud noises

What the purpose of K-complexes

• The suppress cortical arousal while you sleep

• Memory consolidation

• Moving somebody makes them show up.

Describe the third stage of sleep:

N3:

• Delta waves present

• Slow wave sleep

• Sleep walking and talking

What is REM sleep for

• Most important for memory consolidation

• Most dreams happen here

• Body is paralyzed but mind is active

• Waking up during REM prevents dream memory

What controls the Circadian rhythms?

Melatonin produced in the pineal gland across 24 hours

What is an indicator of a person dreaming?

Rapid eye movement

Prefrontal cortex activity is blocked (no logic)

What was Freud’s analysis on dreams

Unconscious thoughts and desires that must be interpreted

1. Manifest content (what happens-monster killed you)

2. Latent content (hidden meaning-got fired)

   Can help us resolve hidden conflict

What is the evolutionary principle behind dreaming?

Threat simulation

Activation synthesis hypothesis

Humans construct dream stories as soon as they wake up in an attempt to decode electrical brain impulses

What is the reasoning behind hypnosis?

• What are the two theories

To retrieve memories and alter them

• Dissociation theory

• Social influence theory

Dissociation theory:

Hypnotism is an extreme form of divided consciousness

Social influence theory

People do and report what is expected of them

What is the purpose of meditation?

Increased attention control

• More alpha waves than a regular relaxed state

• More theta waves in deep meditation

Depressants

Reduce body’s function, think slowly, disrupt REM sleep

• Alchohol

• GABA receptor

Barbiturates

Induce sleep and reduce anxiety

• Depresses the CNS

• Reduces memory, judgement, and concentration

• GABA receptor

Benzodiazapines

Suppressant, opens GABA Cl- channels

• Short and Intermediate for sleep aids

• Long for anti-anxiety

Opiates

Used to treat pain and anxiety

• Act at endorphin receptor

• Lead to euphoria