The first step toward understanding psychology starts by looking at the physiology of the nervous system: the brain and its associated nervous system. Physiology determines nearly everything about the rest of psychology. Imagine buying a truck and discovering it had no motor. Physiology is the motor behind behavior.
On this page you will find the simplest layer of understanding. It, plus what you read in the text should be enough for you to pass the tests. Clicking on the links will give you a deeper layer and may help you understand the topics more fully. Try both out and see what works best for you.
THE NERVOUS SYSTEM (p. 62)
Characteristics
Complexity
Integration
Adaptibility
Electrochemical action
Pathways (more below)
Afferent: pathway for information entering the brain
Efferent: pathway for information exciting the brain
Divisions
Central Nervous System (CNS)
brain and spinal cord (70% of entire nervous system)
Peripheral Nervous System
everything except the CNS
Somatic Nervous System
relays information to brain
executes brain's commands
AKA: voluntary nervous system
Autonomic Nervous System
regulates involuntary functions such as breathing and heart rate
Contains two branches
Sympathetic
prepares the body for action
"fight or flight" response
Parasympathetic
calms the body "rest and digest"
DEMOS
This one is safe. Time yourself for how long you can hold your breath. At some point, your autonomic nervous system will make you breathe. Did you make it to 11 or 22 minutes, the world records? The first is without breathing pure oxygen first, the second is with breathing oxygen first. Here is a WEB PAGE that tells about those records.
This one is impossible: On the count of three, make your heart stop beating :-)
Reaffirms the example of the motor and the truck (see above). Physiology is a complex method for creating behaviors. The nervous system, the endocrine system, genetics, and the environment all play a role.
Two problems are introduced: Identity and Continuity
Identity in this case is best viewed as the answer to this question: "If I knew everything about physiology I could predict your behavior perfectly." I say the answer to that question is "no."
Continuity relates to natural history. Non-scientific accounts of human tend to make human beings special and unrelated to the rest of the natural world. Continuity sees humans as an integrated part of the natural world, or just another species.
There are a variety of techniques for studying the nervous system
Older ones include:
Lesion and Ablation
These invasive methods are not used on humans
Lesions are cuts made in an animal's brain with the idea being to see if behavior changes
Ablations are when selective and localized parts of animal's brain are destroyed by some method to see if behavior changes
Stimulation techniques include:
Electrical stimulation
Tiny electrodes permanently implanted in the brain to see what happens when a mild electric current stimulates a part of an animal's brain
Not used on humans
NEW Delgado stopping a bull from charging: If you look carefully you will see the antenna of the wireless transmitter in Delgado's hand. It is connected to electrodes in the bull's brain that he surgically implanted earlier
In that cartoon Dennis's dad is carrying him home, and Dennis says: "Of course I heard you, you just did not seem mad enough yet."
(If anyone finds that cartoon let me know! I spent two hours looking for it last night!)
Obviously, Dennis's dad had been calling him: Dennis, Dennis, DENNIS!
He was using a graded signal (raising his voice)
Neurons cannot do that. They can only change their rate of firing. Let me substitute the letter "D" for "Dennis" and look at a neuron. (In other words, neurons cannot "raise their voice." Instead, they might fire faster in order to communicate urgency
Here is the early signal D----------D----------D----------D----------D
Here is a later signal D-----D-----D-----D-----D-----D-----D
Here is the last signal D--D--D--D--D--D--D--D--D--D--D
The neuron changes its rate of firing and, thus, changes the information it is relaying
Note that because of the refractory period (see below) the neuron cannot fire without some delay between each action potential
Refractory period
In physiology, refractory means not responding
After a neuron fires it cannot fire again for a short period of time, that is its refractory period
There are two refractory periods in the neuron
Absolute Refractory Period where no stimulus can make the neuron fire again
Relative Refractory Period where, following the Absolute Refractory Period STRONGER than normal stimulation can make the neuron fire again, sooner than normal
Axons in the peripheral nervous system are covered in myelin
Myelin is white, hence the term"white matter"
Brain axons are unmylenated, hence the term "grey matter"
Myelin is laid down by Schwann cells and has two function
Insulate the axon to allow fine motor control
Saltatory conduction where the depolarization jumps (saltare is Latin for to jump) from between on Schwann cell to another. That makes the speed of nerve conduction faster
In humans neurons conduct from 30 to 100 meters/sec
Structures of the Brain and Their Function (p. 73)
The All-or-None law means neuron can only fire one way, fully, no fractional firing
A neuron can be either excited, meaning impulse will continue (EPSP)
Or a neuron can be inhibited, meaning the impulse will stop (IPSP)
Notice how either can convey information
In temporal summation the pre-synaptic neuron fires repeatedly making the post-synaptic neuron more like to fire during its relative refractory period
In the Temporal Summation movie below, the pre-synaptic neuron must fire twice before the post-synaptic neuron will fire
In spatial summation several pre-synaptic neurons firing simultaneously make the post-synaptic neuron more like to fire during its relative refractory period
3-D motor homunculus (shows how some parts of the body are under more precise control/larger = more control)
The size of the body part corresponds with the amount of brain tissue devoted to control. So you can control your hands and fingers better that your feet and toes.
Parietal
front contain sensory homunculus (shows how some parts of the body are more sensitive to tactile stimulation/larger = more sensitivity)
3-D sensory homunculus
Again, but now the size of the body part reflects the amount of brain tissue devoted to sensory understanding. So, your lips and fingers are more sensitive than you back or your feet.
Temporal
parts of this lobe deal with language
Occipital
parts of this lobe deal with vision
Limbic (in some texts)
parts deal with emotional behavior and memory
Much of cortex is "silent" (meaning that no overt is seen when directly stimulating these parts of the cortex)
The presence of dominant and recessive genes aided that process
Dominant genes override recessive genes
Most genetic characteristics are polygenic, meaning they are coded by more than one gene
Molecular Genetics
The study of genetics at its lowest level is molecular genetics
The Human Genome Project identified many gene locations related to health and well-being
Selective Breeding
Selective breeding or eugenics is very controversial
Nazi Germany practiced eugenics by promoting certain people to have children and denying others that opportunity
Tryon (1940) bred successive generations of rats to either excel or not in a laboratory maze. He was successful (p. 94) but discovered that the improvement or deficit was specific to maze running.
Selective breeding is practiced daily in animal husbandry and botany.
Right now, UPS is likely delivering frozen sperm from a prize-winning bull to a rancher somewhere in the USA
That rancher will artificially inseminate his cows to improve some genetic characteristic (e.g., better milk production or better quality of beef)
Thoroughbred race horses, too, are bred (but naturally, it's a rule) to make offspring more likely to win races
A Kentucky Derby winner will earn its owner much more money in stud fees than it ever did winning races
"Gattaca" (movie): describes dystopian future where only genetically superior humans are allowed to breed (Not on test)
Genome Wide Association Methods
Inspired by the Human Genome Project researchers search for groups of genes linked to diseases such as Alzheimer's or depression
Linkage analysis reveals genes that are nearby on chromosomes and are likely to be inherited as a group
Behavior Genetics
Genetics affects behavior, the question is by how much
Twin Studies
The study of identical twins raised apart has yielded much information about that question
Both twins are married to women named Betty and divorced from women named Linda.
One has named his first son James Alan while the other named his first son James Allan.
Both twins have an adopted brother whose name is Larry.
Both named their pet dog "Toy."
Both had some law-enforcement training and had been a part-time deputy sheriff in Ohio.
Each did poorly in spelling and well in math.
Each did carpentry, mechanical drawing, and block lettering.
Each vacation in Florida in the same three-block-long beach area.
Both twins began suffering from tension headaches at eighteen, gained ten pounds at the same time, and are six feet tall and 180 pounds.
Most such identical twins are not so similar, but are more similar to each other than regular siblings are
My take: My wife and I have three children, none are twins, but all are very different in behavior and personality from birth even though they were raised in the same home. Human behavior is the product of genetics and environment.
Genes in the Environment
Genotypes and Phenotypes
a genotype is the genetic information coded by the gene
a phenotype is the expression of the genotype in structure or behavior
Gene expression
The environment, indirectly, and hormones, directly, can turn on or turn off genes
Psychology's Biological Foundation and Health and Wellness (p. 97)
