Chapter 28: Nervous Systems NEW AIM: What types of nervous systems have evolved among animals? I. Nervous Systems A. Most intricately organized data processing

Chapter 28: Nervous Systems

NEW AIM: What types of nervous systems have evolved among animals?

I. Nervous SystemsA. Most intricately organized data processing system on Earth

B. Neurons

i. Nerve cells specialized for carrying signals from one location to another (cellular wires)ii. 50,000,000 per cm3 in your brain

iii. A single neuron may communicate with 1,000 others




B. Neurons

i. Nerve cells specialized for carrying signals from one location to another (cellular wires)ii. 50,000,000 per cm3 in your brain

iii. A single neuron may communicate with 1,000 others




B. Neurons

Fig. 28.1

Central Nervous System (CNS)

- Brain and spinal cord – interneurons and supporting cells

Peripheral Nervous System (PNS)

- Along the central plane of the body

- Peripheral means out to the sides- Sensory neurons, motor neurons and supporting cells




B. Neurons

i. Three general types1. Sensory neurons

- conduct signals FROM sensory receptors to integration centers (brain/spinal cord – CNS)

Sensory receptors (special cells that convert a stimulus into an electrical signal):

a. Pain receptors (nociceptors)b. Thermoreceptors – sense temperature changec. Mechanoreceptors – sense touch, hearing (vibrations in air)d. Chemoreceptors – taste budse. Electromagnetic receptors – rod (grey scale) and cone (color) cells of eye



I. Nervous Systems

Figure of the skin showing neurons involved in sensing temperature (thermoreceptor), pain (nociceptor), light touch, deep pressure, and touching of hair (mechanoreceptors).



I. Nervous Systems

Figure showing “hair” receptor cells found in the ear (organ of Corti). The “hairs” are actually specialized cilia called stereocilia. The cilia will vibrate back and forth. When they bend to the right, they release a chemical signal called a neurotransmitter, which activates the neuron and sends a signal to the brain (mechanoreceptors).



I. Nervous Systems

Electromagnetic receptors

Rod and cone cells are found on the retina (the photographic film of the eye). Rod cells convey electrical signals to the brain, which interprets the signals as shades of grey, while cone cells convey electrical signals down the optic nerves to the a part of the brain that interprets them into color vision.



I. Nervous Systems

chemoreceptorsTaste buds on the tongue are collections of chemoreceptor cells with assorted protein receptors on their surfaces for all sorts of different molecules. When a ligand (ex. Sucrose) binds to the receptors, the receptor opens (it’s a ligand gated channel) causing a signal to be sent through the cell and neurotransmitter to be released, which activates the sensory neurons sending an electrical signal to your brain that is interpreted as the taste of sucrose. What would you taste if I swapped these sensory cells with ones that bind to molecules in a lemon? You would still taste sucrose (sweet) because they are connected to the same neurons and the signal goes to the same part of the brain. In fact, if I connected these neurons to your skin mechanoreceptors, every time I touch your skin you would taste sweetness!!! Think about this!!



I. Nervous Systems

chemoreceptorsThe nose also has chemoreceptor cells that work in a similar fashion to the taste buds, but of course the neurons go to a different part of the brain. What if I took the neurons from the nose that are activated when you small cabbage and connect them to your taste buds? What would happen when you eat something?...you would smell cabbage.




B. Neurons

i. Three general types

3. Interneurons (Integration neurons)

- Interpret the signal and formulate a response (spinal cord and brain)

2. Motor neurons

- conduct a signal from integration center (spinal cord/brain) to an EFFECTOR (that which is effected and performs the response) like muscle cells or gland cells of the adrenal medulla.




B. Neurons

C. Two main divisions of the NS

1. Central Nervous System (CNS)- site of most integration

- brain and spinal cord in vertebrates

2. Peripheral Nervous System (PNS)- nerves that carry signals to and from CNS- Nerves

i. Bundles of neurons (a nerve cell) wrapped in connective tissue- Ganglia

i. Clusters of neuron cell bodies in nerves




This wire on the left would symbolize a nerve. It is not one wire, but many wires wrapped together. The blue plastic would be connective tissue. If you cut a nerve, you will lose the function of whatever those millions of neurons attached to.



I. Nervous Systems

Fig. 28.11

All your Brain receives are electrical pulses

Everything you observe, what you are “seeing” right now is being imagined by your brain based on sensory data.




B. Neurons - sensory, inter, motor

C. Two main divisions of the NS - CNS, PNS

Fig. 28.1

D. The Knee Jerk Reflex (simple reflex)

1. Tap knee

2. Mechanoreceptors (sensor) detect stretch in muscle and a signal is conveyed to CNS (spinal cord) via sensory neurons…

3. …directly to motor neurons, which send the signal to contract the quads

4. …and to interneurons, which bridges to motor neurons to inhibit contraction of hamstrings

http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf







B. Neurons - sensory, inter, motor

C. Two main divisions of the NS - CNS, PNS

D. The Knee Jerk Reflex

1. Tap knee

2. Mechanoreceptors (sensor) detect stretch in muscle and a signal is conveyed to CNS (spinal cord) via sensory neurons…

3. …directly to motor neurons, which send the signal to contract the quads

4. …and to interneurons, which bridges to motor neurons to inhibit contraction of hamstrings

Fig. 28.1

Be able to Label:



I. Nervous SystemsE. The representative neuron…the motor neuron:

Fig. 28.2




1. Cell Body

a. houses nucleus and other organelles

2. Neuron Fibers (2 types)

a. dendrites- extend from cell body

- short, numerous, highly branched- receive INCOMING messages from sensory or interneurons and send them TO cell body

Fig. 28.2




1. Cell Body

a. houses nucleus and other organelles

2. Neuron Fibers (2 types)b. axon

- usually a single fiber- conducts signal TOWARD another neuron or effector cell

- can by VERY long (lower part of spinal cord to toes)

- terminates in a cluster of branches (100’s to 1000’s)

i. Synaptic knobs- on end of EACH branch- relays signal to next neuron or effector

Fig. 28.2




Neurons come in different shapes and sizes



I. Nervous SystemsF. Supporting cells

Fig. 28.2

1. Outnumber neurons 50 to 1 in NS

a. Ex. Schwann cells- form the myelin* sheath around rapid transmission neurons

- wrap the axon like tape around a hockey stick

2. Protect, insult, nourish neurons

*myelin = electrically-insulating phospholipid-rich layer (80% phospholipid, 20% protein) – prevents sodium signal from leaking



I. Nervous SystemsF. Supporting cells


a. Ex. Schwann cells

- form the myelin* sheath around rapid transmission neurons- wrap the axon like tape around a hockey stick


*myelin = electrically-insulating dielectric phospholipid layer (80% phospholipid, 20% protein)

Schwann cell

neuron

Cross section of a neuron axon with a schwann cell wrapped around it.



I. Nervous SystemsF. Supporting cells Fig. 28.2


a. Ex. Schwann cells

- form the myelin* sheath around rapid transmission neurons- wrap the axon like tape around a hockey stick- Nodes of Ranvier


i. Spaces b/w Schwann cells along the axon

ii. Only space where signal can come in or leaveiii. Saltatory conduction = Signal jumps from node to node at 150 m/s or 330 miles/hour - without myelin = 5 m/s

- Multiple Sclerosis (MS)i. Autoimmune disease against Schwann cells




I. Nervous SystemsF. Supporting cells Fig. 28.2





NEW AIM: How do neurons transmit signals?

I. Nervous SystemsG. Nerve Signals and their transmission

Fig. 28.3

1. Resting neurons have potential energy:


AIM: How do neurons transmit signals?


1. Resting neurons have potential energy: Fig. 28.3

i. Electrical charge difference across PMii. Cytoplasm slightly negative relative to IF

iii. Resting potential

- Voltage across PM at rest = -70mV

- mV = milliVolts- Volts describe the affinity for a charged particle or the potential to move

IF = interstitial fluid





iv. What generates the resting potential?

Fig. 28.3http://bcs.whfreeman.com/thelifewire/content/chp44/4401s.swf

http://bcs.whfreeman.com/thelifewire/content/chp44/4401s.swf





iv. What generates the resting potential?

Fig. 28.3

- proteins in cell tend to be negative- sodium-potassium pumps

a. Use ATP to pump 3 Na+ out for every 2 K+ in (more + out than in)

- Na+ is not allowed back in (channels are SHUT)- What about K+?

- K+ channels are open

- K+ allowed to diffuse down concentration gradient

-K+ diffuses out until electromagnetic force pulling it back equals tendency to diffuse (EM in = diffusion out) - see the video below

- cell becomes more negative inside (positive K+ leaving)



I. Nervous Systems

(The all or nothing nerve impulse - aka electrical signal that moves from dendrites to axon)

The Action Potential

Action Potential




2. Nerve signals begin with a change in membrane potentiala. Stimulus

- any factor that causes a nerve signal to be generated like touching your skin and activating a mechanoreceptor or a sucrose molecule binding to a receptor cell on your taste bud, etc…

- wave of voltage that travels along the membrane

*you send a signal from dendrite to synaptic knob or you don’t

b. The Action Potential (a nerve impulse)

- it is ALL or NOTHING (a neuron either fires or it doesn’t)

http://highered.mcgraw-hill.com/olc/dl/120107/bio_d.swf

- They are all the same strength – there is no such thing as a strong action potential or a weak one…




2. Nerve signals begin with a change in membrane potential

b. The Action Potential (a nerve impulse)

i. Voltage-gated channels

- only open at certain membrane potentials

- examples

- voltage-gated Na+ channel

- voltage-gated K+ channel

Opens at a membrane potential of -50mV

Opens at +30mV





b. The Action Potential

1. Neuron is at resting potential (-70mV)Fig. 28.4

McGraw Hill Animation






1. Neuron is at resting potential (-70mV)

2. A stimulus is applied

- causes Na+ channels to open- Voltage begins to rise (depolarization)

- IF voltage reaches “threshold” potential (-50mV),

Fig. 28.4






1. Neuron is at resting potential (-70mV)

2. A stimulus is applied- causes Na+ channels of dendrites and cell body to open

- Voltage begins to rise (depolarization)

- IF voltage reaches “threshold” potential (-50mV), Voltage-gated VG-Na+ channels at the beginning of the axon called the axon hillock will open.

3. Na+ rushes in and inside becomes positive relative to outside

Fig. 28.4






4. Repolarize: Positive potential causes Na+ channels to close and K+ voltage-gated channels to open.

- K+ diffuses down electrochemical gradient

Reminder: Electrochemical gradient = down both a chemical gradient (high to low concentration) and a charge gradient (from + to - in this case)

Fig. 28.4






5. Undershoot (hyperpolarize): K+ voltage-gated channels are slow to close and potential across membranes goes below -70mV…it is now harder for the neuron to fire again, but not impossible (need to get it to -50mV).

Fig. 28.4

6. Na+/K+ pump restores membrane potential to -70mV









3. Action potentials propagate themselves down the neuron

a. The action potential moves along the axon toward synaptic knobs

Fig. 28.5

b. How come they only move in one direction?

- Na+ gates are inactive at +50mV while K+ gates are open

c. Action potential are ALL of NONE and always the same (there are no strong or weak/long or short signals down a neuron)d. So how do we know if something hurts a little or a lot?

- it is all about the frequency of signal being sent (many per second = very painful)



I. Nervous SystemsH. How are signals passed b/w neurons?

1. synapse

a. Junction b/w two neurons or b/w neuron and an effector cell (muscle cell)

Fig. 28.5

b. Two types1. Electrical synapse

- heart and digestive tract muscle

- found everywhere else (CNS, PNS, skeletal muscle, etc…)

- action potential (sodium) itself passes directly b/w neurons / muscle cells through gap junction like structures.

2. Chemical synapses Gap junctions can serve as electrical synapses




a. Synaptic cleft

2. Chemical synapses

Fig. 28.6

- narrow gap (20nm) b/w synaptic knob and receiving neuron

b. Electric signal to chemical signal to electric signal

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__chemical_synapse__quiz_1_.html

c. Action potential causes voltages-gated Ca++ channels to open on knob

d. Ca++ causes vesicles with neurotransmitter to fuse with membrane

http://brainu.org/files/movies/synapse_pc.swf





Fig. 28.6

e. Neurotransmitters (NT)- the chemical signal- stored in vesicles at synaptic knob

- NTs diffuse across cleft and binds to receptors (typically sodium Ligand-gated ion channels, which aim to excite the neuron or chlorine gated ion channels with make the inside more negative and therefore serve to inhibit the neuron from firing)

- new action potential generated if threshold potential (-50mV) is reached

Q. How is a one-way signal ensured at synaptic cleft?





Fig. 28.6

e. Neurotransmitters (NT)

- Where will the NTs go after binding the receptors on the effector cell?

- They must somehow be cleared from the synaptic cleft otherwise the effector will keep getting the signal (ex. Your muscle just keeps contracting)

- NT’s are either broken down by enzymes, taken up via endocytosis by the sending neuron and reused, or diffuse away



I. Nervous SystemsI. Making complex information processing possible

1. Many inputs on a single neuron

2. Each sending neuron can secrete

i. different quantity of NT

ii. Different kind of NT

- excitatory = open Na+ channels

3. Rate of signaling is the sum (called summation) of ALL the EPSP and IPSP. If the IPSP are stronger than the EPSP, no signal sent and vice versa.

Green = excitatory post synaptic potential (EPSP)

Fig. 28.7

- inhibitory = open Cl- or K+ channels

Red = inhibitory post synaptic potential (IPSP)http://brainu.org/files/movies/synapse_pc.swf



I. Nervous SystemsJ. Types of neurotransmitters

1. Most are small nitrogen-containing molecules

2. Types

i. Acetylcholine (Ach)

- signaling in brain - *****motor neuron to muscle (effector) signaling

- makes skeletal muscles contract





2. Types

ii. Biogenic amines (neurotransmitters derived from amino acids)

- epinephrine- norepinephrine - serotonin- dopamine

a. Examples

b. Important in CNS

- serotonin and dopamine - effect sleep, mood, attention, learning- schizophrenia associated with excess dopamine- depression associated with reduced levels or norepinephrine and serotonin- Parkinson’s associated with lack of dopamine

dopamine serotonin





2. Types

iii. Amino acids

- aspartate- glutamate- glycine- GABA (gamma aminobutyric acid) – major inhibitory NT of the CNS

a. Examples

b. Important in CNS

- 100X more GABA in brain than all other neurotransmitters combined

GABAAspartate





2. Types

iv. peptides

- endorphins- substance P

a. Examples (both involved in pain perception)

v. Dissolved gas

a. Nitric oxide (NO)

- memory storage and learning- relaxes smooth muscle

Substance P



I. Nervous SystemsK. Many drugs act at chemical synapses

1. Caffeine

2. Nicotine

3. Alcohol (ethanol)

4. Prozac

5. Valium, Xanax, amphetamines, cocaine, LSD, mescaline, opiates, etc…

- counters inhibitory neurotransmitters

- binds and activates acetylcholine receptors in nervous system

- believed to increase inhibitory effect of GABA in brain

- blocks REMOVAL of serotonin from synapse

Chapter 30: How animals Move

NEW AIM: What types of motor systems have evolved?

LOCOMOTION



IIB. Chemotaxis vs. Phototaxis

A. Chemotaxis – process by which a cell directs their movement depending on a chemical in the environment – taxis = to move (hence the word taxi).

Ex. 1. Movement of sperm towards the egg (egg secretes chemicals that sperm are attracted to);

2.Movement of macrophages to a site of bacterial infection (broken cells release a chemical attractant)

3. Movement of bacteria to a high concentration of glucose

These are all examples of positive chemotaxis (move towards the chemical)

There can also be negative chemotaxis (move away from the chemical).



IIB. Chemotaxis vs. Phototaxis

b. Phototaxis – process by which an entire organism directs their movement depending the stimulus of light (this is NOT a plant moving towards light, which is called phototropism).

Ex. 1. Algal cell moves toward light (positive phototaxis)

Mov

emen

tEx. 2. Moths or fruit flies attracted to light



VI. Muscle contraction and movementA. The skeleton and muscles interact in movement

B. Muscle system is an EFFECTOR of the nervous system

Fig. 30.7

D. Insertion of a muscle

i. Portion attached to bone that moves Insertion of bicep

Insertion of tricep

C. MUSCLES CAN ONLY CONTRACT (SHORTEN)

E. The ORIGIN is the attachment to the non-moving bone

Origin of bicep

Origin of tricep



VI. Muscle contraction and movementE. Extensor

Fig. 30.7Extensor

i. Muscle that extends or straightens the bones at a joint

Ex. Tricep is an extensor - it contracts and straightens arm at elbow F. Flexor

i. Muscle that bends a joint to an acute angle

Ex. Bicep is a flexor - it contracts and bends arm at elbow

Flexor

Bicep and Tricep are antagonistic muscles

ALL animals have pairs of antagonistic muscles



VI. Muscle contraction and movementG. Tendons (dense connective tissue)

i. Connect muscles to bones

Ex. Achilles tendon

Fig. 30.7



VI. Muscle contraction and movementH. Ligaments

i. Connect bones to bones



VI. Muscle contraction and movementI. Three types of muscles

i. smooth

ii. cardiac

iii. skeletal

- movement caused by CONTRACTION in ALL 3 types

- Contraction caused by sliding of actin and myosin filaments past each other inside cells…




i. Smooth muscle

a. involuntary muscles (autonomic NS) in arteries and veins, gastrointestinal tract, bladder, uterus

b. nonstriated

- simply means that actin and myosin do not have clear organized arrays

c. smooth muscle cells connected by gap junctions in tissues (allow action potential to pass from one cell to next) - electrical synapse

d. Single nucleus per cell




ii. Cardiac muscle

a. Single nucleus per cell

b. striated

- actin and myosin have clear organized arrays

c. connected by gap junctions in tissues (allow action potential to pass from one cell to next) - electrical synapse

d. Involuntary (autonomic NS)




iii. Skeletal muscle

a. Voluntary (intentional physical movement; somatic NS)

c. striated

- actin and myosin have clear organized arrays

d. Stimulated by nerves at neuromuscular synapses

b. Muscle cell = single, large, multinucleated fiber

e. Action potential along surface of muscle cell stimulates calcium release into cytoplasm, which in turn causes contraction


AIM: How do muscle fibers contract?

VIII. Neuromuscular junction

Fig. 30.10



IX. How does a motor neuron make a muscle fiber contract?Fig. 30.10

1. Action potential (AP) reaches synaptic knob

2. Acetylcholine released into synaptic cleft3. Sodium moves through muscle fiber (just like a neuron)

4. AP travels along T-tubules (membranous tubules that fold in through cells) deep into the fiber

Neuromuscular junction video on website



IX. How does a motor neuron make a muscle fiber contract?

Fig. 30.10

1. Action potential (AP) reaches synaptic knob

2. Acetylcholine released into synaptic cleft3. Sodium moves through muscle fiber (just like a neuron)

4. AP travels along T-tubules (membranous tubules that fold in through cells) deep into the fiber

5. AP causes Ca++ to be released from sarcoplasmic reticulum (SR = ER) of muscle cell (myocyte) into cytoplasm

Muscle action potential video on website




Fig. 30.10

Acetylcholine will be broken down by the membrane-bound enzyme (protease) acetylcholinesterase in the neuromuscular junction in order to terminate the signal to the muscle.


NEW AIM: How do muscle fibers contract?

VII. Muscle contractionA. Skeletal muscle

i. Muscle composed of bundles of fibers (cells)

- striation = alternating light and dark band of myofibrils

iii. Sarcomere - repeating unit of the myofibril (region b/w two Z lines) – you see sarco- you think muscle

ii. Muscle fibers (cells) contain numerous myofibril (contractile protein structures)

- thin filament: two strands of actin polymers and one strand of regulatory protein

- thick filament: staggered array of multiple myosins

- dark band vs. light band

Fig. 30.8


NEW AIM: How do muscle fibers contract?

VII. Muscle contractionB. Sliding-filament model

Fig. 30.9

Sarcomere contraction video on website




Fig. 30.9

1. ATP binds to myosin head (causes detachment from actin)

2. ATP hydrolyzes to ADP and Pi

- energy used ratchet back the head

- head is now in an unstable (high energy) state

3. Head binds to actin

4. ADP and Pi are released resulting in the power stroke

5. ATP binds, head releases, repeat again, but grab the next actin closer to Z-line

Sliding filament video on website




Fig. 30.8

1. ATP binds to myosin head (causes detachment from actin)

2. ATP hydrolyzes to ADP and Pi

- energy used ratchet back the head

- head is now in an unstable (high energy) state

3. Head binds to actin

4. ADP and Pi are released resulting in the power stroke

5. ATP binds, head releases, repeat again, but grab the next actin closer to Z-line

Aside: Rigor Mortis– when an animal dies, it becomes stiff (hence why we call dead people stiffs). This is because ATP is needed to release the myosin head from the actin filaments. No ATP, no release, muscle can’t relax.




Fig. 30.10

6. Myosin binding sites on actin usually blocked by regulatory strand (troponin and tropomyosin)

7. Ca++ binds to part of regulatory strand (troponin) of thin filament, which causes tropomyosin to move off myosin binding site so myosin can bind.

Muscle action potential video on website




Fig. 30.10

http://www.tvermilye.com/pmwiki/pmwiki.php?n=Animation.Video12



X. Vocabulary for a skeletal muscle cell

A. Sarcolemma: plasma membrane

B. Sarcoplasmic reticulum (SR): endoplasmic reticulum

C. Sarcomere: single unit of the myofibril

D. Sarcoplasm: cytoplasm


NEW AIM: What kinds of nervous systems have evolved?

ANIMAL BEHAVIOR



II. Behavior in animals (Chapter 37)

1. Simple relfexes

i. Automatic response to simple stimuli

Fig. 28.1

ii. Controlled at spinal level in vertebrates

A. Innate behavior

- Behavior that appears to be performed the same way by ALL individuals of a species




2. Fixed action patterns (FAPs)

i. Can only be performed as a whole from start to finish

Fig. 37.3A

ii. Once an animal initiates an FAP, it usually carries sequence to completion regardless of external stimuli

A. Innate behavior

- Behavior that appears to be performed the same way by ALL individuals of a species (a complex reflex)

Graylag goose retrieving an egg






Fig. 37.3B


A. Innate behavior


iii. Built into the neurons (a complicated reflex)

FAPs in a European Cuckoo

iv. Activated by a specific stimulus






Mating dance


A. Innate behavior


iii. Built into the neurons (a complicated reflex)

Web building

iv. Activated by a specific stimulus

yawning




B. Learned behavior

- a change in the way an animal behaves based on experience (i.e. learning)

Table 37.4




B. Learned behavior

1. Habituation (desensitization)

- loss of response to a stimulus after repeated exposure

Ex. Poke a snail once and it retracts into shell, keep poking and it will no longer retract (nervous system learns to ignore the stimulus)

Do you feel the closes touching your skin all over your body right now?

Do crows remain afraid of a scarecrow forever?




B. Learned behavior

1b. Sensitization (opposite of habituation)

- A repeated stimulus creates a stronger reflex response.

Ex. Rub your arm continuously…

At first your arm will warm up, but eventually it will become painful




B. Learned behavior

2. Imprinting

- imprinting is learning that interacts closely with innate behavior

- limited to a specific time period and is generally IRREVERSIBLE

-important in forming offspring/parent relationship in many species:




B. Learned behavior

2. Imprinting

Fig. 37.5

- imprinting is learning that interacts closely with innate behavior

- limited to a specific time period and is generally IRREVERSIBLE

-important in forming offspring/parent relationship in many species:




B. Learned behavior

2. Imprinting

Fig. 37.5

i. Konrad Lorenz experiment

- found critical imprinting period for graylag goose to be 2 days after hatching

- The critical period for imprinting is innate, but the actual imprinting is learned

- Lorenz was “imprinted” into the minds of the goslings as “momma”

http://www.youtube.com/watch?v=LGBqQyZid04




- associates bell with food

Pavlov’s experiment (1927)i. Food (unconditioned stimulus; UCS) causes salivation (unconditioned response; UCR)

ii. Ring bell (neutral stimulus), no salivation occursiii. Ring bell when giving food, salivation occurs

iv. Eventually, ring bell alone (conditioned stimulus; CS) causes salivation (conditioned response; CR)

B. Learned behavior3. Associative learning - learn that a specific stimulus or response is linked to

a reward of punishment

i. Classical conditioning - association of an involuntary or automatic response with an environmental stimulus






a. Press lever when light is green

- Skinner Box:

ii. Operant or Instrumental conditioning - conditioning a voluntary response (a behavior) to a stimuli (reinforcement/punishment)

- get food (positive reinforcement; reward)

b. Press lever when light is red

- get shocked (positive punishment)

- B.F. Skinner (1930’s)

- associates response to reward/punishment






Reinforcement vs. Punishment

ii. Operant or Instrumental conditioning - conditioning a voluntary response (a behavior) to a stimuli using a reward (reinforcement)

Reinforcement – anything that makes the behavior more frequent

Punishment – anything that makes the behavior less frequent

Positive vs. Negative (has nothing to do with something that is positive or negative in nature like a lolly pop vs. a slap in the face)

Positive – when something is given to the organism

Negative – when something is taken away from the organism

Now put the terms together…






1. Positive reinforcement


- You will make the behavior more frequent by giving something to the organism (a reward)

Ex. You jump in the air, I give you five bucks…guess what you do again…

2. Negative reinforcement

- You take something away to reinforce the behaviorEx. A rat is placed in a cage and given a mild shock until is presses a lever. When it releases the lever, a another shock is delivered causing is to press the lever again.

Ex. The beeping noise in the car goes off when you put your seat belt on.






3. Positive punishment


- You will make the behavior less frequent by giving something to the organism Ex. The rat presses the lever and gets shocked. The shock will cause the rat to press the lever less often.

4. Negative punishment

- You will make the behavior less frequent if you take something away.

Ex. Your cell phone is taken away if your grades are poor. Getting poor grades is the behavior we want to extinguish and we take away the cell phone to accomplish this.

Ex. Every time you turn in your homework late, I give you detention. This will reduce the frequency of turning in ones homework late.

http://www.wagntrain.com/OC/Part2.htm





a reward of punishmentDifferences Between Classical & Operant Conditioning:

- Classical conditioning is passive on the part of the learner. - Operant conditioning relies on the learner to actively participate in the learning process.

- In operant conditioning reinforcers act as incentives for learning. - Classical conditioning, on the other hand, does not provide incentives.






iii. Extinction

- organisms eventually unlearn the conditioned response in the absence of reinforcement – ring the bell often without giving food




iv. Trial and error learning (operant conditioning in nature)

Fig. 37.6B

B. Learned behavior3. Associative learning

- Behavioral act linked to a negative effect

- learn to associate behavioral act with a positive or negative effect

- learn that a specific stimulus or response is linked to a reward of punishment




i. Mating dance/song

c. Intraspecific interactions (interactions within a species1. Behavioral displays ( tend to be innate - FAPs)

ii. Agnostic displays (dog wagging its tail)

iii. Antognisitc displays (hair standing up when threatened)

iv. “waggle dance” of the scout honeybee

http://www.youtube.com/watch?v=-7ijI-g4jHg




i. Ranking of individuals based on social interaction

c. Intraspecific interactions2. Pecking order or dominance hierarchy

ii. Social heirarchy of a group

iii. Minimizes violent intraspecific aggressions

- alpha wolf = dominant wolf in pack

- omega wolf = lowest ranking member




- area defended by most land-dwelling species from intrusion by other members of same species (conspecifics = same species)

c. Intraspecific interactions3. Territoriality

- used for mating, nesting, and/or feeding (i.e. resources)

- shown by a minority of species

Gannets at a nesting ground Cheetah spray-urinatingSunbathers




i. Circadian rhythms

c. Intraspecific interactions4. Behavioral cycles

- daily cycles of behavior

Ex. - Sleep and wakefulness

- based on natural light/dark cycles

- Feeding patterns

- brainwave activity

- hormone production

- cell regeneration




i. Behavior that reduces the fitness of the individual, while increasing the fitness of the recipient

c. Intraspecific interactions5. Altruism

- ex. Female workers in honeybee hives are sterile, but they spend their life helping the one fertile queen reproduce.

How is this a selective advantage for the alleles of the non-reproducing individuals?

ii. Kin selection

- the genes coding for altruistic behavior will increase if those benefiting from the act also carry those genes (related individuals help each other since they have similar genes)

Kin selection




iii. Recipricol altruism and non-kin cooperation

c. Intraspecific interactions5. Altruism

- help another individual if the act can be repaid at a later date

Ex. Certain dolphins will help unrelated members raise their young in return for help with their young later, but nothing compares to human non-kin cooperation…this is our “trick”…our biggest advantage and may all stem from out ability to kill from a distance (to throw). Distance killing allows us to coerce each other into doing “the right thing”, without threat to ourselves (there is little threat to a gunman pointing a gun at a person

even if the gunman is much smaller and weaker). The coercion allows us to control out desire to be selfish and “force” people to help non-related individuals. We have since been able to evolve minds that behave in this fashion, which is the only reason I am able to speak to you now.

Documents

Chapter 28: Nervous Systems NEW AIM: What types of nervous systems have evolved among animals? I. Nervous Systems A. Most intricately organized data processing