Unit 1 (Part 3): Biological Bases of Behavior (Sensation Edition)

sensation

process by which our sensory receptors and nervous system RECEIVE and REPRESENT stimulus energies from our environment

perception

the process of organizing and INTERPRETING sensory information to make sense of the world around us
-involves the brain’s interpretation of sensory inputs, which can be influenced by past experiences, expectations, and context
-MAKING MEANING OF RAW DATA

transduction

-CONVERSION of sensory stimuli into neural impulses that can be understood by the brain
-transformation of physical energy into electrochemical signals
-allows the brain to interpret and perceive sensory information

absolute threshold

MINIMUM amount of sitimulation required for a stimulus to be detected by a sensory system
-represents the point at which a stimulus becomes noticeable to an individual at least 50% of the time

just-noticeable difference (JND)

the smallest change in a stimulus that can be detected by an individual
-MINIMAL difference needed for a person to perceive a change has occurred
-measures SENSITIVITY to DIFFERENCES in stimulus intensity

weber’s law

-the perceived difference in a stimulus must be PROPORTIONAL to the original intensity of the stimulus
-the more intense something is, the stronger the change must be to notice a difference

sensory adaptation

process by which sensory receptors become LESS responsive to constant stimuli over time

synesthesia

-a condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in another sensory pathway
-when senses mix together

retina

light-sensitive inner surface of the eye containing PHOTORECEPTOR CELLS that CONVERT LIGHT into NEURAL SIGNALS

rods

-photoreceptor cells
-located in retina
-responsible for vision in LOW LIGHT conditions and DETECTING MOVEMENT
-provide BLACK and WHITE vision
-highly sensitive to LIGHT

cones

photoreceptor cells
located in retina
-responsible for COLOR vision and detail in BRIGHT LIGHT
-allows us to perceive colors and fine visual details

fovea

contains lots of CONE CELLS (NO ROD CELLS)
central area of retina
-responsible for SHARP CENTRAL VISION

blind spot

area on the RETINA where the OPTIC NERVE EXITS the eye
-lacks photoreceptor cells

ganglion cells

neurons
located in the retina
-RECEIVE visual information from bipolar cells and TRANSMIT it to the BRAIN via the OPTIC NERVE
-play a crucial role in PROCESSING VISUAL SIGNALS and RELAYING them to the BRAIN for further interpretation
-DETECT CHANGE IN LIGHT

lens

-transparent structure in the eye that FOCUSES LIGHT onto the RETINA
-adjusts its shape to help the eye properly reflect light
-allows for clear vision at different distances

accomodation

-process by which the LENS CHANGES ITS SHAPE to FOCUS ON OBJECTS AT DIFFERENT DISTANCES
-allows for CLEAR VISION of both NEARBY and DISTANT objects by ADJUSTING the CURVATURE of the lens

nearsightedness

-common vision condition where CLOSE OBJECTS APPEAR CLEAR, but DISTANT OBJECTS APPEAR BLURRY
-occurs when the EYEBALL is TOO LONG or when the CORNEA is TOO CURVED, causing light to focus IN FRONT OF the RETINA instead of on it

farsightedness

vision condition where DISTANT OBJECTS are seen more CLEARLY than close ones
-occurs when the EYEBALL IS TOO SHORT or CORNEA is TOO FLAT, causing light to focus BEHIND the RETINA rather than directly on it

trichromatic theory

-theory proposing that color vision is based on THREE types of CONE RECEPTORS, each sensitive to different wavelengths of light (red, green, and blue)
-3 types of cones:

1. short cones/S cones: sensitive to BLUE light

2. medium cones/M cones: sensitive to GREEN light
3. long cones/L cones: sensitive to RED light
-brain COMBINES SIGNALS FROM CONES to create the perception of a wide range of colors

opponent-process theory

-theory suggesting that color vision is based on PAIRS of OPPOSING COLOR PROCESSES
(red-green, blue-yellow, black-white)
-activation of one color in the pair INHIBITS the other
-leads to perception of color afterimages and explains certain aspects of color vision

afterimages

visual sensations that persist AFTER a stimulus is removed
-occur due to TEMPORARY OVERSTIMULATION OF CONE CELLS in the retina
-leads to a brief perception of an INVERTED or COMPLEMENTARY image

dichromatism

-type of color vision deficiency where an individual has only TWO types of FUNCTIONING CONE CELLS
-results in difficulty DISTINGUISHING BETWEEN COLORS, specifically reds and greens

monochromatism

-form of color blindness where an individual has only ONE type of FUNCTIONING CONE CELL or NONE at all
-results in an INABILITY to perceive colors, causing people to see the world in shades of GRAY

blindsight

-phenomenon where individuals with DAMAGE to their VISUAL CORTEX can respond to visual stimuli WITHOUT CONSCIOUSLY PERCEIVING them
-implies that some visual processing can occur unconsciously

prosopagnosia

neurological condition
-inability to recognize familiar faces, including one’s own face, despite intact vision and intellect
FACE BLINDNESS

wavelength

distance between sound wave PEAKS
-shorter _______ = higher-pitched sounds
-longer ________ = lower-pitched sounds

amplitude

-measure of the INTENSITY or LOUDNESS of a sound wave
-represented by the HEIGHT of PEAKS
-greater _______ = louder sounds
-lower ________ = softer sounds

pitch perception

the brains’s INTERPRETATION of the FREQUENCY of sound waves, determining whether a sound is high or low in tone
-higher frequencies are perceived as higher pitches
-lower frequencies are perceived as lower pitches

place theory

the idea that different PARTS OF THE INNER EAR detect different SOUND FREQUENCIES
high pitches are sensed near the entrance of the cochlea
low pitches are sensed near the end of the cochlea

frequency theory

-theory of pitch perception proposing that the FREQUENCY of a sound wave directly corresponds to the RATE at which AUDITORY NEVER FIBERS FIRE
-higher frequency sounds lead to faster firing rates, leading to higher perceived pitches

volley theory

-theory of pitch perception proposing that GROUPS of AUDITORY NEURONS FIRE in RAPID SUCCESSION (volleys) to encode the FREQUENCY of sounds ABOVE 1000 Hz
-allows the brain to perceive pitches that EXCEED the FIRING RATE of individual neurons

sound localization

-brain’s ability to determine the LOCATION of a SOUND SOURCE in space
-relies on cues such as differences in arrival time and intensity between the ears, as well as spectral cues, to LOCATE SOUNDS

conduction deafness

hearing impairment
-caused by problems with the outer or middle ear
-ex: damage to the ear canal, ear drum, or middle ear bones
-typically results in difficulty hearing SOFT sounds and can often be treated medically or surgery
-SOUND CAN’T REACH INNER EAR

sensorineural deafness

hearing loss
-caused by DAMAGE to the INNER EAR or AUDITORY NERVE
-results in difficulty hearing SOFT sounds and understanding speech, and is often permanent
-common causes: aging, exposure to loud noise, certain medical conditions, and damage to cochlea

sensory interaction

-the principle that one sense can influence another
-shows how senses WORK TOGETHER to create our overall perception of the world

olfactory systems

-responsible for SMELL
-receptors in the nose detects smells and send signals to the brain via the OLFACTORY NERVE
-thalamus helps process this information, which lets us identify different colors

pheromones

chemical substances
-released by animals, including humans
-trigger SOCIAL or BEHAVIORAL responses in others of the same species
-play a role in COMMUNICATION, MATING, and TERRITORIAL MARKING

gustation

-sense of TASTE
-involves receptors on the TONGUE that detect different flavors

supertasters

individuals that are HIGHLY SENSITIVE to taste
-experience flavors more intensely, especially bitterness

medium tasters

-individuals that have an AVERAGE SENSITIVITY to taste
-experience flavors moderately

nontasters

-individuals that are LESS SENSITIVE to taste
-experience flavors less intensely than others

warm/cold receptors

-specialized sensory neurons
-located in skin
-detect CHANGES in TEMPERATURE
-warm receptors respond to increases in temperature, cold receptors respond to decreases in temperature
-HELP US PERCEIVE AND REGULATE BODY TEMPERATURE

pain

NOT A SENSATION
-emotional response to stimuli

gate control theory

-theory that proposes that the experience of pain is controlled by a neural “gate” in the spinal cord
-gate can OPEN to ALLOW PAIN SIGNALS to be transmitted to the brain or CLOSE to BLOCK them

phantom limb

-sensation of pain or other feelings in a missing limb
-occurs due t othe brain’s continued perception of the limb, even though it’s no longer there

vestibular sense

-sense of BODY ORIENTATION and MOVEMENT
-includes BALANCE and SPATIAL AWARENESS
-relies on receptors in the inner ear that detect changes in HEAD POSITION and MOVEMENT
-helps to maintain stability and coordinate bodily movements

semicircular canals

fluid-filled structures in inner ear
-detect rotational movement of the head
-play a crucial role in VESTIBULAR SENSE
-helps to maintain balance and coordination by SENDING SIGNALS to the brain about CHANGES IN HEAD POSITION AND MOVEMENT

kinesthesis

-sense of body movement and position
-includes awareness of MUSCLE and JOINT SENSATIONS
-allows us to PERCEIVE and CONTROL body’s movements
-provides feedback to brain about position and orientation of body parts