Behavioral Neuroscience

Front 1

Which color has the shortest wavelength? The longest?

Back 1

Blue, around 400. Red, around 750.

Front 2

What are some of the main parts of the eye?

Back 2

Retina, Fovea, Optic Nerve, Cornea, Pupil, Lens

Front 3

The Retina

Back 3

Lines the back of the eye
Light is converted to neural signals to be sent to the brain.
3 layers - photoreceptor layer, bipolar cell layer, ganglion cell layer

Front 4

Retinal Pigment Epithelium

Back 4

These pigmented cells form a layer behind the retina.
Stops light from bouncing back out/ being reflected
Some animals have a more reflective layer to see better in the dark

Front 5

What are the 3 layers of the retina?

Back 5

1) Photoreceptor Layer
2) Bipolar Cell Layer
3) Ganglion Cell Layer

Front 6

Photoreceptor Layer

Back 6

Contains photoreceptors, rods, cones
By the back of the eye

Front 7

Bipolar Cell Layer

Back 7

Contains Bipolar Cells
Connects photoreceptors to the third layer
The horizontal cells are like an octopus reaching across multiple photoreceptors

Front 8

Ganglion Cell Layer

Back 8

Contains ganglion cells
Sends axons to the brain - Form optic nerve
Light comes into the ganglion layer and is sent back

Front 9

Optic Disk

Back 9

Blind spot
No photoreceptors, just axons

Front 10

Optic Nerve
AKA
Cranial Nerve

Back 10

Very back of eye, where info is sent

Front 11

Cornea

Back 11

Light bends here
(Coming in from the top goes to the bottom back)

Front 12

Rods and Cones

Back 12

Photo pigments are in the outer segments of the rod
Sensitive to light
Transmitters released from base of rods

Front 13

Cones

Back 13

Most prevalent in central retina, found in fovea
Sensitive to moderate to high levels of light
Provide info about hue
Provide excellent acuity

Front 14

Rods

Back 14

Most prevalent in the peripheral retina, not found in the fovea
Sensitive to low levels of light
Provide only monochromatic info
Provide poor acuity

Front 15

Fovea

Back 15

Central focus of vision (center of retina)
contains only cones, no rods
central vision (all other is peripheral, where rods are)

Front 16

Fovea

Back 16

The blind spot- 1 eye fills in the blind spot of the other

Front 17

Wavelength Examples

Back 17

Blue or short wavelength cones - almost 550
Rods - A little over 600
Green or medium wavelength cones - 650
Red or long wavelength cones - about 675

Front 18

Phototransduction

Back 18

Light is converted into electrical signals in the retina

Front 19

Phototransduction - Receptor Responses in Darkness

Back 19

1) photopigment phodopsin consists of retinal and opsin bound together
2) Retinal is in 11-cis form
3) Photoreceptor cell produces cGMP
4) cGMP causes sodium channels to open
5) Protoreceptor cell is depolarized
6) Increased release of glutamate
(rod in depolarized state - glutamate released)

Front 20

Phototransduction - Receptor Responses When Light is Absorbed

Back 20

1) Retinal absorbs a photon
2) Retinal changes to all-trans form. Rhodopsin molecule breaks apart
3) Enzymes are released, which break down cGMP
4) Sodium channels close (no cGMP)
5) Photoreceptor becomes hyperpolarized. (The more light absorbed, the more hyperpolarized)
6) Decreased release of glutamate

Front 21

Graded Potentials - Action Potentials

Back 21

Photoreceptor - hyperpolarizing membrane potential
Bipolar Cell - depolarizing membrane potential
Ganglion Cell (to the brain) - Recording of action potentials
AP in 3rd step

Front 22

Cones and Bipolar Cells

Back 22

On-Center/Off-Surround Receptive Field (when light hits the center, it turns on, hits the surrounding, turns off)
Light hits the cones and starts process of sending AP's
Surrounding area of cones inhibit the gang. cells (send fewer AP's)

Front 23

On- and Off-center ganglion cells

Back 23

When there's no illumination @ all, gang.'s continue to fire (still watching, waiting, alive)

Front 24

Mach bands - Hermann Grids

Back 24

When it looks like there is a darker line between two shades (when there isn't)

Front 25

Visual Processing Pathways

Back 25

Contains Suprachiasmatic Nucleus, Lateral Geniculate Nucleus, Superior Colliculus

Front 26

Suprachiasmatic Nucleus

Back 26

Circadian Rhythms

Front 27

Superior Colliculus

Back 27

Sensory- info

Front 28

Lateral Geniculate Nucleus (LGN)

Back 28

3 parts
1) Magnocellular Layer
2) Parvocellular Layer
3) Koniocellular Sublayer

Front 29

Magnocellular Layer

Back 29

Transmits info from the rods
bigger cells
two inner layers; form, movement, depth, and small differences in brightness

Front 30

Parvocellular Layer

Back 30

Color info from cones
Smaller cells
Four outer layers; color and fine details
(red and green)

Front 31

Koniocellular Layer

Back 31

sublayers between the magno. and parvo.
transmits info from short wavelength (blue) cones to the primary cortex

Front 32

Occipital Lobe

Back 32

V1 = Primary visual cortex (layer 4)
V1 - V2 - segregated to different pathways
V4 = Colors, Motion = MT
V3 = Form (shapes, textures, edges)

Front 33

Simple Cortical Cells

Back 33

Related to lines
Tested on monkeys

Front 34

Complex Cortical Cells

Back 34

Larger receptive fields
No off regions
Sensitive to movement

Front 35

Ocular Dominance Columns

Back 35

Method = computer to control stimulus and record and process data from camera

Front 36

Orientation Columns

Back 36

Method = computer to produce different stimulus orientations and process data from camera

Front 37

Trichromacy Theory

Back 37

3 color processes account for all the colors we're able to distinguish
Red, blue & green are the primary colors

Front 38

Young & Helmholtz

Back 38

From Trichromacy Theory, we have 3 types of photoreceptors
We have 3 types of cones
Light of different wavelengths will stimulate these cones by different amounts
The system must compare activity in all 3 to determine which wavelengths of light you're seeing

Front 39

Opponent Process Theory

Back 39

Attempts to explain color vision in terms of opposing neural processes (& fill in gaps Trichromacy Theory leaves)
Includes afterimages & Complementary colors

Front 40

Afterimage

Back 40

If we view colored stimuli for an extended period of time, we will see an afterimage in a complementary color

Front 41

Complementary Colors

Back 41

colors that cancel each other out to produce a neutral gray or white

Front 42

Hering (Opponent Process Theory)

Back 42

We have 2 types of color opponent cells:
red-green opponent cells
blue-yellow opponent cells

Front 43

Color Vision

Back 43

Today, based on Trichromatic & Opponent Process Theory

Front 44

Retinotopic Map

Back 44

in the visual cortex
adjacent retinal receptors activate adjacent cells in the visual cortex

Front 45

Form Vision

Back 45

The detection of an object's boundaries and features (such as texture)

Front 46

What & Where Pathways

Back 46

Where = Dorsal stream
What = Ventral Stream

Front 47

Parahippocampal Place Area (PPA)

Back 47

Strong category-selective region that responds to houses, landmarks, & indoor/outdoor scenes
Responds weakly to other types of stimuli, like faces, bodies, etc

Front 48

Germ Layers

Back 48

Formed w/in the first week of contraception
3 layers:
Ectoderm - Top layer (skin & nervous tissue)
Mesoderm - Muscles, bones
Endoderm - Bottom layer (internal organs)

Front 49

Neural Tube

Back 49

Retained in mature brain as the ventricle system & central canal of spinal cord

Front 50

Neural Development

Back 50

Cell Proliferation
Migration (as cells divide, they migrate out)
Differentiation (once they get to the right spot)
Circuit Formation (Synaptogenesis) (Connections formed with near & far neighbors, Form synapses with other neurons)
Neuron Death (Apoptosis)
Rearrangement of connections (Circuit Pruning & refinement of synapses)

Front 51

Cell Proliferation
(Neurogenesis)

Back 51

New cells born
Cells divide & multiply & multiply
New neural cells formed in ventricular zone
Symmetrical & Asymmetrical Division

Front 52

Migration

Back 52

Once the daughter cell migrate from the progenitor
Neurons just work their way up the radial glia

Front 53

Differentiation

Back 53

Daughter cells differentiate into neurons or glia
Neural Tube differentiate in 2 directions:
1) along the rostral-caudal axis
2) between the dorsal & ventral halves
Many different genes & chemicals responsible

Front 54

Circuit Formation
(Synaptogenesis)

Back 54

Start connecting to neighbors through use of growth cones
Growth cones respond to chemical & physical properties of the extracellular environment to reach their destinations - extend our in different directions, find a partner & influence other neurons to form a synapse)
Once axons & dendrites are in place, both pre- & postsynaptic structures influence synaptic development
The cell's major neurotransmitter is influenced by the postsynaptic neuron

Front 55

Rearrangement of Connections

Back 55

Because so many & extra were formed
Those getting used are strengthened, while the others die away

Front 56

Symmetrical Division

Back 56

lateral (getting bigger and farther away)

Front 57

Asymmetrical Division

Back 57

1 cell stays as a progenitor cell, the other becomes something in the nervous system

Front 58

Radial Glia

Back 58

Special glia with fibers that grow radially outward from the ventricular zone to the surface of the cortex
Provide guidance for neurons migrating outward during brain development
Doesn't just push another up, it goes through the layer & forms a new one above it (so 6th formed first, then 5th...)
@ any 1 time, a billion neurons working up the glia

Front 59

Growth Cone

Back 59

Just sorta move & feel around
A molecule is released that attracts the growth cone
Other release those that repulse the cone

Front 60

Apoptosis
(Cell Death)

Back 60

Neurons compete for nerve growth factors, & those that fail to obtain this stimulus die
Caspases
(synapses follow same thing, called pruning)

Front 61

Caspases

Back 61

suicide/grim reaper
Exists in all neurons @ all times

Front 62

NGF

Back 62

Nerve Growth Factor
Keeps neurons alive & happy

Front 63

Visual Synapses

Back 63

Peak at 1 year of age
Pruning - NGF comes from postsynaptic side,
send NGF back & sent up the terminal

Front 64

Myelination

Back 64

Occurs from spinal cord rostrally towards the forebrain
Sensory systems myelinated before motor systems
Most occurs early on, but continues till about 20 years old

Front 65

Critical Windows

Back 65

Ability to rearrange synapses can only occur during this time (others can continue throughout lifespan)
Examples :
Imprinting (ducklings)
Vision (develop ability to see with both eyes & each aspect of vision involves competition)
Language (even if learn a new one later, you'll never sound like a native)

Front 66

Input organizes the LGN

Back 66

right and left eyes provide different inputs - start off as overlapping, but eventually are segregated
can put a patch on strong eye while young to improve the weak one

Front 67

End of Critical Periods

Back 67

Multiple hypotheses:
axon growth ends
synapses mature
the presence of absence of neurotrophins influence plasticity

Front 68

Aging Nervous System

Back 68

The human brain is considered mature at 20 yrs
Brain weight begins to decrease at 45 yrs
People with college degrees have better preserved circuits (use it or lose it)

Front 69

Alzheimer's

Back 69

Begins with mild memory loss, then progresses to loss of language, social skills and problem solving.
Eventually, it's fatal
Typically doesn't occur until around 70 yrs
APOE4 gene is correlated with it
No current meds reverse it, but some can slow it down

Front 70

Emotion

Back 70

•Emotions are subjective experiences that arise spontaneously and unconsciously in response to internal and external events.
•Emotions have different components:
–Physical
•Behavioral (facial expressions, body language)
•Autonomic (rapid heartbeat, etc.)
•Hormonal (adrenaline, stress hormones)
–Cognitive - conscious experience or feeling
–Valence (positive or negative)

Front 71

Purpose of emotion

Back 71

•Arousal
•Approach/avoidance
•Communication

Front 72

James-Lange Theory

Back 72

specific pattern of autonomic arousal leads to specific emotions

Front 73

Biological Connection to Emotions

Back 73

The Autonomic Nervous System
–Flight or fight response
–ANS produces different patterns of arousal during different emotional states based on valence

Front 74

The Amygdala

Back 74

Imaging studies show more activity in the amygdala when viewing expressions of fear.
•Klüver-Bucy syndrome reduces fear.
•Human damage to the amygdala produces difficulty identifying fear and anger.
•The amygdala contains many benzodiazepine receptors.

Front 75

The Cortex & Emotion

Back 75

•Hemisphere lateralization
for emotion
–Left hemisphere damage
results in depression
–Dichotic listening tasks

Front 76

Affective Blindsight

Back 76

–The ability of a person who cannot see objects in his or her blind field to accurately identify facial expressions of emotion while remaining unconscious of perceiving them; caused by damage to the visual cortex.
–The subcortical input (from the superior colliculus and the pulvinar, a large nucleus in the posterior thalamus) appears to provide the most important information for this task

Front 77

Different Emotions Produce Patterns of Brain Activation

Back 77

Fear – amygdala; Disgust - insula
•Feeling excluded from a game produced activity in the cingulate gyrus, an area that responds to physical pain.

Front 78

Types of Muscle

Back 78

•Smooth muscles:
•Digestive tract
•Arteries
•Reproductive system
•Striated muscles:
•Skeletal muscles
•Cardiac muscles of the heart

Front 79

Muscle Fibers

Back 79

•Sarcomere: single segment of a myofibril.
•Z line: boundary of each sarcomere.
•Thin filaments are made of actin
•Thick filaments are made of myosin

Front 80

Muscle Fiber Contraction

Back 80

•In the resting muscle, troponin prevents interactions between actin and myosin.
•The arrival of an action potential leads to an internal release of calcium.
•Calcium binds with troponin and allows actin and myosin to interact.
•The myosin filaments slide past the actin filaments, shortening the sarcomeres and contracting the fiber.
•Calcium is taken up again into internal organelles, troponin prevents actin and myosin interaction, and the fiber relaxes.

Front 81

Muscles

Back 81

Can only contract
Additional muscles allow joints to rotate

Front 82

Alpha Motor Neurons

Back 82

produce muscle contraction through their activity at the neuromuscular junction
The gray matter of the spinal cord is larger in segments serving the arms and legs due to large numbers of alpha motor neurons.

Front 83

The Motor Unit

Back 83

consists of an alpha motor neuron and all the fibers it controls
•Size of a motor unit corresponds to its function.
–Neurons serving slow twitch fibers have small cell bodies, innervate few fibers and produce little force.
–Neurons serving fast twitch fibers have larger cell bodies, innervate more fibers and produce greater force.

Front 84

Control of Muscle Contraction

Back 84

•A single action potential may be sufficient to produce contraction.
•Varying amounts of force may be supplied by:
- varying the firing rate of alpha motor neurons. - recruitment (activating more motor units as more load is placed on a muscle).

Front 85

Control of Alpha Motor Nuerons

Back 85

•Alpha motor neurons receive input from:
–Muscle spindles
–Golgi tendon organs
–Brainstem and motor cortex neurons
–Spinal interneurons

Front 86

Circadian Rhythm

Back 86

•Any rhythmic change that continues at close to a 24-hour cycle in the absence of 24-hour cues
–body temperature
–cortisol secretion
–sleep and wakefulness
•In the absence of time cues, the cycle period will become somewhat longer than 24 hours

Front 87

Zeitgebers

Back 87

environmental event that resets and entrains rhythm

Front 88

Biological Rhythms

Back 88

Rhythm, Time Frame, Example
Circadian, Daily, Sleep-wake cycle
Ultradian, More than once a day, Eating Cycles
Circannual, Yearly, Migration

Front 89

Consequences of shift in clock

Back 89

•Shift work
–more accidents, psychological problems, less sleep
•Jet Lag – phase delays easier than advances