AP Psych Unit 1B: Sensations

Thalamus

The brain's sensory relay center, responsible for sending touch information from the body to the somatosensory cortex ***Is bypassed by the sense of smell, it does not happen here

Limbic System

In the brain, involved in emotion, memory, and behavior regulation. Includes the hippocampus, amygdala, and hypothalamus. Olfactory signals bypass thalamus and go straight here and to the olfactory cortex

Olfactory System

The sensory system responsible for sense of smell. Involves receptors in the nasal cavity that detect chemicals in the air and relay signals to the brain (transduction)

Transduction

Sensory stimuli is converted into electrical impulses in the nervous system, allowing the brain to interpret them. ***taste and smell use transduction

Gustation

Sense of taste that involves the detection of dissolved substances by taste buds on the tongue, allowing perception of flavors.

Taste Buds

Specialized structures on the tongue that contain taste receptors

5 primary taste categories

sweet, sour, salty, bitter, umami (savory taste, often linked to proteins)

Taste Receptors

Located within the taste buds, detect chemicals dissolved in saliva and sends signals to the brain via gustatory pathway

Skin Receptors

detect pressure, temperature, and pain (they send signals to the brain for processing)

Mechanoreceptors

detect pressure and texture (ex. touching a smooth surface)

Thermoreceptors

detect changes in temperature

Nociceptors

detect pain (damage to tissues)/ only sends signals if threshold is met

Somatosensory Cortex

located in the parietal lobe (processes touch sensations)/ the cortex reflects the sensitivity of different areas in the body (ex. hands and lips have more representation due to their high sensitivity)

Gate Control Theory

suggests the spinal cord contains a neurological “gate” that can block or allow pain signals to pass to the brain.

Difference between large/small nerve fibers

Small- carries pain signals

Large- carries other touch signals (ex. pressure)/ when large fibers are activated, the gate blocks some pain signals from reaching the brain and perception of pain is reduced

Phantom Limb Sensation

feeling sensations, like pain in a limb that has been amputated because the brain can still produce sensations as if the limb is still there

Oleogustus

the sixth category of taste, new term for taste of fat, plays a role in food preferences

Vestibular Sense

Maintains our balance, posture, and spatial orientation by detecting changes in the position of our head. Crucial role in our ability to move smoothly and coordinate actions.

Semicircular Canals

three fluid-filled tubes in the inner ear, each one is in a different plane (horizontal, vertical, diagonal) to detect different types of head movements. This bends tiny hair cells within the canal, which send signals to the brain, and it uses this information to adjust posture and balance.

Vertigo

brain receives conflicting signals from the vestibular system and other senses leading to a spinning sensation

Kinesthetic System

Body movement and position awareness: the body’s ability to detect the position and movement of muscles, joints and limbs. Allows you to know where your body parts are without looking at them.

Sound Waves (amplitude, frequency and wavelength)

bands of compressed and expanded air that our ears detect due to changes in air pressure/ they vary in amplitude (different loudness) and frequency and wavelength (measured in hertz and we experience as differing pitch)

Frequency

Number of sound wave cycles per second/ determines pitch**

Pitch

a sound’s highness or lowness, depends on frequency**

Amplitude

height of sound waves (determines loudness**)

Pinna

(in outer ear) visible part of the ear that collects sound waves & funnels them into the ear canal/ helps capture sound from the environment

Ear/ Auditory Canal

(in outer ear) A tube that channels sound waves from the pinna to the eardrum/ amplifies the sound waves as they travel toward the middle ear

Eardrum

(in outer ear) Thin flexible membrane that vibrates when sound waves hit it, vibrations mark the transition from the outer ear to middle ear & start process of turning sound waves into mechanical energy

Ossicles

(in middle ear) Three tiny bones: malleus, incus, stapes (stirrup) that amplify vibrations from eardrum & transfer them to inner ear

Eustachian

(in middle ear) a canal that connects the middle ear to the throat/ helps equalize air pressure on both sides of the eardrum (ex. when ears pop during a flight)

Cochlea

(inner ear) Small fluid-filled, converts the mechanical vibrations from ossicles into electrical signals/ inside cochlea is the basilar membrane lined w/ hair cells

Auditory Nerve

(inner ear) Carries the electrical signals generated by the hair cells in the cochlea to the brain, where they are interpreted as sound

Place Theory

how we hear high pitched sounds/ idea that different frequencies of sound waves stimulate different places or locations along the basilar membrane in the cochlea (acts like a piano, where each location along the membrane corresponds to a particular pitch)

Frequency Theory

how we hear low pitched sounds/ idea that the rate (frequency) at which the auditory nerve sends electrical signals to the brain matches the frequency of the sound wave, helping us detect lower-pitched sounds, so the entire basilar membrane vibrates at the same frequency as the sound wave

Volley Theory

how we hear higher pitched sounds (especially between 1000 Hz and 4000 Hz)/ idea that individual neurons can’t fire on their own to keep up with high frequency sound waves, so instead groups of neurons work together by taking turns firing rapidly

Sound Localization

helps determine where sounds are coming from

Conduction Deafness

problems w/ conducting sound waves to cochlea

Sensorineural Deafness

damage to the cochlea or auditory nerve

Cochlear Implants

helps restore hearing by stimulating the auditory nerve 

Transduction in the Retina

the retina converts light into neural signals through photoreceptors/ retina captures light that enters the eye and helps translate it into images you see —> light passes through the lense at front of the eye and hits the retina —> photoreceptors change light energy into an electrical signal —> travels through the optic nerve and into the brain to become the p

Photoreceptors

cells inside your retina that react to light

Cornea

Clear outer layer at front of the eye/ helps focus light coming into eye

Pupil

Black circle in middle of the eye/ right behind cornea/ controls how much light enters the eye by getting bigger or smaller

Iris

Colored part of the eye/ responsible for changing size of pupil/ regulates light energy

Lens

behind pupil/ bends to focus light onto the retina

Retina

back of the eye before optic nerve/ where light is turned into signals/ where rods and cones are that help us see

Fovea

small area in center of the retina/ where vision is sharpest/ used for detailed tasks like reading

Optic Nerve

nerve that sends visual information from the eye to the brain for processing

Rods

detect light and are used in low-light conditions (black & white)

Cones

detect color and are concentrated in the fovea, the center of the retina “cones see color”

Lens Accommodation**

lens changes shape to focus light on the retina for clear vision

Trichromatic Theory

retina contains three types of color receptors (red, green, blue) and their combination allows us to perceive the full color spectrum

Opponent-Process Theory**

certain cells in the brain are stimulated by some colors and inhibited by others, helping to explain afterimages

Afterimage

an image that appears to be seen in the eyes after a period of exposure to original image

Blind Spot

the spot in the retina where the optic nerve connects/ there’s no light sensitive cells so this part of the retina cannot see

Color Vision Deficiencies (Dichromatism and Monochromatism)

Dichromatism - two types of cones

Monochromatism - only one type of cone or none, leading to color blindness

Prosopagnosia

can see faces visually, but cannot recognize people’s faces

Sensation

process where our sensory receptors and nervous system receive and represent stimuli from the environment

Absolute Threshold

minimum intensity of a stimulus that can be detected 50% of the time

Just-Noticeable Difference

smallest detectable change in a stimulus

Weber’s Law

size of the JND is proportional to the intensity of the stimulus

Sensory Adaptation

constant exposure to a stimulus leads to a decrease in sensitivity over time

Sensory Interaction

idea that one sense may influence another (ex. smell can affect taste)

Synesthesia

rare condition where stimulation of one sensory pathway leads to involuntary experiences in a second sensory pathway (ex. seeing colors when hearing music)

Priming

exposure to one stimulus can influence how we perceive a subsequent stimulus (ex. being primed w/ the color yellow —> more likely recalling yellow objects)

Ganglion Cells

neurons located near the inner surface of the retina

Suprachiasmatic Nucleus (SCN)

in the hypothalamus, controls circadian rhythms 

Circadian Rhythm

a 24-hour biological clock that regulates sleep, wakefulness and other bodily functions

Jet Lag

the result of disruptions in the circadian rhythm/ due to irregular sleep patterns —> impacts mood, alertness and cognitive abilities

Altered States of Consciousness

any conditions that different significantly from a normal waking state, affecting awareness and perception

NREM Stage 1

lightest sleep, marked by alpha waves (“alpha means awake”) & hypnagogic sensations (hallucinations or falling sensations)/ transition between wakefulness and sleep

NREM Stage 2

deeper relaxation, characterized by sleep spindles & EEG patterns showing more synchronized brain activity

NREM Stage 3

deepest sleep, slow delta waves (“delta means deep sleep”) & hardest stage to wake from/ crucial for physical restoration, muscles relax, blood pressure & breathing rate drop

REM Sleep

Paradoxical sleep (brain’s active but body is paralyzed), where dreams happen, role in memory consolidation

Delta & Alpha Waves

delta - deep NREM sleep, slow brain waves

alpha - awake state, relaxed

REM Rebound

natural response to sleep deprivation, stress, or drug/alcohol use that causes a person to have more REM sleep than normal (body will try to catch up)

Activation Synthesis Theory

idea that dreams are the brain’s way of making sense of random neural activity

Consolidation Theory

dreams help process and solidify memories and experiences from the day

Narcolepsy

sudden & uncontrollable “sleep attacks” often directly into REM sleep

Hypnagogic Sensation and Hallucinations

sensations of falling or hearing sounds as you drift into sleep, often occurs in NREM stage 1

REM Sleep Behavior Disorder

acting out dreams due to lack of muscle paralysis

Insomnia

difficulty falling asleep or staying asleep

Sleep Apnea

breathing rapidly, disrupts sleep and causes excessive daytime sleepiness

Somnambulism

sleepwalking, typically occurs in NREM 3

Importance of Sleep

physical restoration, memory consolidation, and emotional regulation