Bio Psych Midterm 3

Front 1

Receptive Field Sensitivity Depends on 2 Things

Back 1

• Individual receptor sensitivity—different types of receptors have different sensitivities—rods are more light sensitive than cones

Senstiivty depends on how sensitive each receptor Is itself
• Rods are more light sensitive- dim light rods more likely to be more activated- night vision- allow us to discirminate stuff in light– don’t need as much light to activate a.p.
• Density of the receptive field—The total number of receptors in the receptive field

Front 2

Can You Think of Examples of Differences in Receptive Field Density?

Back 2

• Density differences across the body—
• Density differences of different species—
• More touch receptors in certain body areas- concentrated in certain places- face, hands, lips, and tongues
• Species- dogs have way more smell receptors in their noses and thus have a more powerful sense of smell- more smell receptors

Front 3

Receptive Fields

Back 3

Each sensory modality has thousands to millions of receptors
• Receptive field: the array of receptors for a given sensory modality
• Each receptor receives slightly different information
• These differences allow us to locate events in time and space
• Senses arranged in receptive fields- instead of 1 sensor have 1000s sensing the environment
• Each diff. receptors receiving diff. info
• Ex. back of hand- poked it– where exact point of pen is poked.. Certain receptors release signal– farther away from pen poked, less receptors will be active

Front 4

Sensory Coding and Representation

Back 4

· The presence of a sensory stimulus is encoded by a change in the number of action potentials fired by the sensory receptor per unit time, or the rate of discharge

Front 5

· Stimulus intensity—

·

Back 5

greater intensity like a brighter light or louder noise is encoded by a greater discharge rate

Front 6

Stimulus quality—

Back 6

red vs. green light for example can be coded for by activity of different receptors or by different levels of discharge in the same receptor

Front 7

factors contributing to perception.

Back 7

The nature of the sensation

· Context in which sensory events take place

· Our emotional state

· Past experiences and memories

· Depends on nature of sensation- are we seeing. Smelling, feeling something

· Same sensory signal can have different context from another

· Ex. footsteps behind you on campus walking to class vs. walking in a dark alley alone– contex changes- same stimulus, different perception

· Emotional state- ex. just saw a scary movie, now hearing footsteps in dark alley– past experiences- concerned about the sound of the foot steps– what differs is what your brain is doing with the

· Pic B- same length in line– same context– how you see things a lot to do with context, emotional state, etc.

Front 8

Fovea—

Back 8

region containing the largest density of photoreceptors; vision is actually sharpest here; makes up <1% of visual field but eye movements called saccades driven by neurons in the midbrain move your fovea around your visual field to give a bigger more detailed picture

Front 9

· Blind spot—

Back 9

region containing no photoreceptors because the sensory neuron axons exit the eye here as the optic nerve but the other eye, and photoreceptors around each blind spot “fill in” missing visual info

· Almost blind in every part of the eye (retina) except for the fovea= 20/20 vision

· Focus fovea on whatever you want to look at

· Blind spot- no photo receptors– compensate for blind spot of other eye

· Periphial part of retina- bad as sensing color

Front 10

RODS

Back 10

· Larger & cylindrical

· More numerous

· More sensitive, respond to dim light

· Responsible for night vision

· Only one type of light absorbing pigment

Front 11

CONES

Back 11

· Smaller and tapered at end

· Less numerous except in fovea

· Less sensitive, respond to bright light

· Responsible for color, fine detail, and motion

· 3 different types of light absorbing pigment

Front 12

Flow of Visual Information into the Brain

Back 12

Retinal ganglion neurons send their axons to the lateral geniculate nucleus of the thalamus

· The lateral geniculate nucleus neurons sends their axons to the striate cortex

Front 13

The Striate Occipital Cortex is the Primary Visual Cortex

Back 13

· Visual information is roughly processes in the striate occipital cortex to start to identify color, form, and movement

Front 14

Ventral Stream & Temporal Cortex—

Back 14

the “what” path, object identification

Ventral stream- pathway that tells us what we’re looking at

Front 15

Dorsal Stream & Parietal Cortex:

Back 15

the “where” path, spatial location

Dorsal stream- send axons up the back of the brain– comes up back of brain– sent to the parietal lobe—that info. tells us where an object is

Front 16

The Visual System Processes 3 Components:

Back 16

· Form or shape

· Color

· Motion

Front 17

what are the 5 different tastes?

Back 17

· SWEET-surface receptors bind to glucose and similar sugars,

· SALTY-ion chanllel lets Na+ enter cell,

· SOUR-ion channels lets H+ ions into cell,

· BITTER-binds to a wide range of aromatic compounds,

· UMAMI- “savory”- binds to the amino acid glutamate

· FAT??– may be 6th taste, may bind to fatty acids

Front 18

What Are Some Factors Influencing Taste?

Back 18

· Emotion

· Smell of the food

· Factors influencing taste

· Emotional state- when were sad or anxious, foot tastes less good– comfort foods

· Past experiences– food that’s have sickened us taste less good, new/strange food taste less good than familiar ones

· Genetics– some people have certain taste proclivites and aversions, particulary for bitter tastes– bitter snese helps us dteremine that we might be eating something that’s poisionus

· Other sensory inpurs- smell, tetxure, color– flavor vs. tatse & OFC

Front 19

how smell affects human behavior.

Back 19

· Nearly all reactions to smell are learned—babies show no difference in reaction to good vs. bad smells, there are no universally recognized smells across cultures

· Mothers can identify blood offspring but not stepchildren, and siblings can identify blood siblings but not half- or step-siblings—may be responsible for the Westermarck Effect

· Women tend to find the smell of men who are genetically different from them more pleasant, which may be a mechanism by which genetic variation is increased during mate selection

Front 20

Know what the loss of the senses of smell and taste are called and what their primary symptoms are.

Back 20

Anosmia—Loss of Sense of Smell

· Causes—genetics, some medications, neurodegenerative diseases, damage to olfactory nerve, strokes or tumors affecting the cortical smell centers, nasal polyps

Front 21

Know the main neural structures involved in the neural control of movement and their main functions.

Back 21

Frontal cortex—initiates and plans movement

· Brainstem—relays commands to the spinal cord

· Spinal cord—transmits signals to lower motor neurons

· Muscles—carry out movements

· Basal Ganglia—regulates the force of movements

· Cerebellum—detects and corrects errors in movement

· Somatosensory system—provides sensory feedback about movement

Front 22

Know the three main parts of the frontal cortex and their role in movement functions.

Back 22

Prefrontal cortex—initiates movement goals

· Premotor cortex—organizes movement patterns

· Motor cortex—actually sends out the commands for producing specific movements through different patterns of muscle activation

Front 23

What do you think a lesion or damage to the prefrontal cortex might result in?

Back 23

o lesions to the prefrontal cortex often result in impulsive or inappropriate behaviors

Front 24

What do you think lesions to the premotor cortex might result in?

·

Back 24

o lesions in the premotor cortex affect the ability to put together complex movements

Front 25

What do you think lesions to the motor cortex result in?

Back 25

lesions to the motor cortex result in paralysis or inability to carry out specific movements

Front 26

muscle

Back 26

Consists of long, cylindrical cells called muscle fibers

· Special proteins inside muscle fibers called contractile proteins pull on one another, causing contraction or shortening of muscle fibers

· Contracting muscles pull on bones and move joints and produce movements

Front 27

, motor unit,

Back 27

Each muscle fiber gets innervated by a single motor neuron

· However a single motor neuron can innervate multiple muscle fibers—motor unit

Front 28

agonist,

Back 28

a muscle that causes specific movement or possibly several movements to occur through the process of its own contraction

Front 29

antagonist.

Back 29

a muscle that acts in opposition to the specific movement generated by the agonist

· Most movements require the coordinated, alternating activation of agonists and antagonists

Front 30

Know the two different types of movement symptoms associated with damage to the basal ganglia, which diseases are associated with each, and which pathway (direct vs. indirect) they are associated with

Back 30

· Hyperkinetic symptoms and the direct pathway—involuntary and/or excessively forceful movements—Huntington’s chorea and Tourette’s Syndrome tics

· Hypokinetic symptoms and the indirect pathway—rigidity & decreased movement production—Parkinson’s Disease

· Basal ganglia regulates the force of movements and suppresses involuntary movements

Front 31

Know the 4 different types of somatosensory information and what they respond to.

Back 31

Nocioception—(skin) pain

· Thermoreceptor—(skin) temperature

· Hapsis—(skin) fine touch and pressure

· Proprioception—(muscles, tendons, and joints) body awareness, muscle stretch and joint angle

Front 32

Know the functions of sensory reflexes and what defects in them represent.

Back 32

Sensory Reflexes

· Sensory information entering the spinal cord synapses on lower motor neurons

· Activation of the stretch receptor causes activation of motor neurons, resulting in a twitch

· Reflexes allow us to respond much more rapidly than when we process sensory information in the brain

Front 33

· What does testing our reflexes tell us?

Back 33

o testing of reflexes tells us about how well our sensory motor neurons are working but tells us nothing about the brain

Front 34

Know the main components of human thought or cognition.

Back 34

4 Main Components of Cognition

· Perception—the ability to recognize & interpret sensory stimuli

· Attention—ability to sustain concentration on a particular object, action or thought

· Memory—the ability to store & recall information

· Executive Functions--abilities that enable goal-oriented behavior, such as the ability to plan and execute a goal, impulse control, problem solving, coming up with new ideas, etc.

Front 35

How Do We Study Cognitive Function?

Back 35

· Psychological testing

· Brain imaging

· Psychophysiological methods

Front 36

Psychological Tests of Cognitive Function

Back 36

· Perception tests—how long it takes to recognize an object

· Attention tests—how long can a subject focus on something

· Memory tests—remembering numbers, symbols, words, etc.

· Executive function tests—are people successful in solving a particular problem—Erickson Flanker Task, Stroop Task