PSY100 Lecture 4 Flashcards

Spatial vs. Temporal Resolution

Spatial: Measures precise location of brain activity (e.g. it happened in the amygdala)

Temporal: Measures exact timing of that brain activity

Electroencephalogram (EEG) (and Advantages + Disadvantages)

Brain cap measuring electrical voltage changes over time

Advantages: EXCELLENT Temporal Resolution for fast events like sleep

Disadvantages: POOR Spatial Resolution since it cannot pin down exact small brain structures

Positron Emission Tomography (PET) (and Advantages + Disadvantages)

Using a Synthetic Radiotracer like FLUORODEOXYGLUCOSE (FDG) to measure metabolic activity

Advantages: Shows exactly where a chemical or metabolic issue is located in the brain structure

Disadvantages: DECENT Spatial Resolution, better than EEG but worse than MRI; POOR Temporal Resolution due to 20-30 minute tracer accumulation lag

MRI vs. fMRI (and Advantages and Disadvantages)

MRI: Scan showing grey vs white matter

fMRI (Functional MRI): Scan tracking BOLD signal (Blood Oxygen-Level Dependent); tracks changes in blood oxygen and flow

Advantages: GREAT Spatial Resolution; best out of EEG and PET for studying brain activity
Disadvantages: Decent Temporal Resolution; couple seconds lag between activity and signal but still better than PET

Weaknesses of Lesion Studies

Lesions (like damaged brains) are rarely neat, cannot prove direct experiment causality, and can create too limited theories about what a brain region does

Sensation vs. Perception

Sensation: Receiving, collecting, and amplifying info from environment (BOTTOM-UP; 5 senses taking raw info from environment)

Perception: Interpreting/Organizing this info so we can understand + react to it (TOP-DOWN AND BOTTOM UP); Top-Down is brain using past experiences to make sense of the information

General Structure of a Sensory Pathway

Sensory Organ → Receptive Cells → Peripheral Nerve → Thalamus Relay (Thalamus routes all 5 senses EXCEPT SMELL/OLFACTION from body to cerebral cortex for conscious awareness) → Specific Cortical Areas

Cortical Area for Each Sense

Visual: Occipital

Hearing: Temporal

Touch: Parietal

Taste: Insula

Smell: Piriform

Structure of Vision Pathway

Eye → Photoreceptors → Optic Nerve → Thalamus → VISUAL/OCCIPITAL CORTEX (Image processor; takes signals from eyes and turns it into images you can see)

Rods vs. Cones

Rods: Photoreceptors packed in PERIPHERY for dim light and night vision

Cones: Photoreceptors packed in FOVEA/CENTRE for bright light and fine detail

Trichromatic Color Theory

Young-Helmholtz Theory; every perceived colour is created by blending RED, GREEN, and BLUE cone signals together

Opponent-Process Color Theory

Young-Helmholtz Theory; colour vision relies on three competing channels: red vs. green, blue vs. yellow, and black vs. white, where fatiguing the neurons for one colour causes brain to temporarily see its opposite as an afterimage

Types of Perceptual Visual Adjustments

Color Constancy - Adjusting object colour based on background lighting like the dress illusion

Spectral Sensitivity - Shift where yellow looks brightest in daylight while blue shifts in darkness

Contrast Enhancement - Process that detects brightness or colour transitions and increases contrast immediately around them

Blindsight

Phenomenon where people who are blind can respond to visual stimuli without consciously seeing them (because part of their brain is still processing visual information without them knowing it)

Auditory Pathway

Eardrum → Ossicles (malleus, incus, stapes; 3 smallest bones in human body) → Cochlea fluid → Hair Cells (receptors) → Vestibulocochlear Nerve → Thalamus →Temporal Cortex

Vestibular System

Fluid-filled canals in inner ear beside cochlea that process our perception of balance

Proprioception vs. Nociception

Proprioception: Body's unconscious ability to sense its own position, movement, and force in space without needing to look

Nociception: Nervous system's process of detecting harmful or potentially harmful stimuli (e.g. as intense heat); DIFFERENT from pain, since Nociception is just the biological alarm system

Taste Pathway

Taste buds → Bipolar cells (receptor) → Cranial nerves → Brainstem structures → Thalamus → Insula Cortex

Taste Map vs. Supertaster Bud Theory

Taste Map: FALSE theory that says certain parts of tongue are responsible for certain tastes (like bitter, sour, salty)

Supertaster Bud: People experiences flavours with different intensity depending on amount of taste buds they have

Olfactory/Smell Pathway

Starts with olfactory receptors in OLFACTORY EPITHELIUM (turns odours into electrical signals for brain); Bipolar cells (receptors)→ Glomerulus (hub that collects and sorts those signals before sending them deeper into brain) → Olfactory nerve → Piriform Cortex → Orbitofrontal Cortex

Sensory Interactions

McGurk Effect: Visual illusion showing that mismatched lip movements can trick brain into hearing a completely different sound ("ba" + "ga" = "da")

Synesthesia: When one sense triggers another (like tasting colours)

Absolute Threshold

Lowest stimulus intensity at which we can detected the stimulus correctly more than 50% of time

Subliminal Stimulus

Any sensory signal (e.g. image, sound, or word) presented below your threshold of conscious awareness, meaning it is too faint or shown too quickly for you to consciously notice, yet your brain still processes it (e.g. a single frame in movie flashing “BUY POPCORN”)

Signal Detection Theory Matrix

2x2 framework for detection performance; Hit (present + "yes"), Miss (present + "no"), False Alarm (absent + "yes"), Correct Rejection (absent + "no")

Response Bias

Your tendency to lean toward guessing "Yes" or "No" based on what you stand to gain or lose; Bias TOWARD detection (e.g. $10 reward per frog found) creates maximum hits, but high false alarms, Bias AGAINST detection (e.g. $10 penalty per wrong guess) creates maximum correct rejections, but high misses

Just Noticeable Difference (JND) and Weber's Law

JND: KNOWN AS DIFFERENCE THRESHOLD; Minimum change in a stimulus that a person can detect >50% of the time

Weber's Law: States that JND is PROPORTIONAL to background intensity (harder to notice 5kg added to 50kg than 5kg added to 1kg due to ratio of each; 10% vs. 500%)

Conscious vs. Unconscious

Conscious: Automatic Behaviours and Implicit Memory

Unconscious: Controlled Behaviours and Explicit Memory

Theories of Why We Sleep

Brain maintenance (clearing toxic waste), Memory consolidation (process that changes short-term memories into long-term), Emotional regulation, Energy conservation, and Dreaming

Sleep Stages and How To Distinguish

NREM1 & NREM2 (Light Sleep): Theta waves (4-7 Hz)

NREM3 (Deep Sleep): Delta waves (slowest, <4 Hz)

REM Sleep: Fast, awake-like waves (resembling Beta waves, >13 Hz)

Chronotypes

Preferences/variations in sleep-wake cycle

Theories of Why We Dream

Dream Protection: Freud's theory; Dreams act like a guardians, turning annoying noises or thoughts into harmless stories so you stay asleep)

Evolutionary: Dreams aren't random, but are survival tool to help humans survive and pass on their genes; like a “SURVIVAL SIMULATION”)

Activation-Synthesis: Dreams are your brain's attempt to make stories from random electrical signals produced during sleep

Neurocognitive: Dreaming is just your normal everyday brain thinking out loud while you sleep.

Overfitted Brain Hypothesis: Dreams create weird, random scenarios so your brain doesn't get locked into strict daily routines and stays adaptable (your mind might dream about driving a flying boat through a jungle so it stays adaptable when real life throws something weird at you if you spend all day in real life driving the same route to work)

Hypnosis and Factors Correlated

Induced trance-like state where about 20% are highly responsive; Eagerness/Expectation, Openness, and Focus make you more sensitive to hypnosis

Hypnosis Theories

Dissociative: Hypnosis causes a split in consciousness, where one part of consciousness follows the hypnotist while another part independently observes

Socio-Cognitive: Hypnosis is NOT a split of consciousness; instead, people are simply acting how they believe a hypnotized person should act (so like placebo effect)

Integrative: Combines both views, arguing that hypnosis involves genuine cognitive state changes (dissociation) AND role-playing working together simultaneously

Near-Death Experiences (NDEs)

Characteristics: Transformative, calming experiences during impending death evaluated on Greyson NDE (Near-Death Experience) scale

Causes: Impending death or can be chemically mimicked by ketamine, DMT, or hypoxia (oxygen deprivation)

Consequences: Transformative; changes in how you view the world after the Near-Death Experience

What Disorders Meditation Can Treat

Stress, anxiety, depression, and chronic pain