Download Unit 3 "Cliff Notes" Review

UNIT 3 – BIOLOGICAL BASIS OF BEHAVIOR
Unit 3 Overview
Module 9 – Biological Psychology & Neurotransmission
Module 10 – The Nervous & Endocrine Systems
Module 11 – Studying the Brain & Older Brain Structures
Module 12 – The Cerebral Cortex
Module 13 – Brain Hemisphere Organization & the Biology of Consciousness
Module 14 – Behavior Genetics: Predicting Individual Differences
Module 15 – Evolutionary Psychology
9.1 – Biology, Behavior, and Mind
•Phrenology -Franz Gall was correct in his assumptions that different parts of the brain do control different aspects of behavior… but that’s
about it
•Biological psychology -study the links between biological activity and psychological events
9.2 – Neurons
Neurons
The body’s information system is built from billions of interconnected cells called neurons.
A nerve cell, or a neuron, consists of many different parts:
Parts of a Neuron
Cell Body: Life support center of the neuron.
Dendrites: Branching extensions at the cell body. Receive messages from other neurons.
Axon: Long single extension of a neuron, covered with myelin[MY-uh-lin] sheath to insulate and speed up messages through neurons.
Terminal Branches of axon: Branched endings of an axon that transmit messages to other neurons.
Action Potential
A neural impulse. A brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms in and out
of channels in the axon’s membrane.
Threshold
threshold: the level of stimulation required to trigger a neural impulse
Each neuron receives excitatory and inhibitory signals from many neurons. When the excitatory signals minus the inhibitory signals exceed a
minimum intensity (threshold) the neuron fires an action potential… or if the excitatory party animals outvote the inhibitory party
poopers, the party’s on.
9.3 – How Neurons Communicate
Synapses
Synapse[SIN-aps] –a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
This tiny gap is called the synaptic gap or cleft (which is less than a millionth of an inch wide!)
Neurotransmitters
Neurotransmitters are chemicals released from the sending neuron that travel across the synapse and bind to receptor sites on the receiving
neuron, thereby influencing it to generate an action potential.
Reuptake
Excess neurotransmitters in the synapse are reabsorbed into the sending neurons through the process of reuptake.
How is Flushing a Toilet Like a Neuron Firing
•All-or-nothing principle–the toilet either flushes completely or not at all; it doesn’t flush a little or a lot
•Direction of impulse–the toilet only flushes one way, the impulse can’t come the other direction (you hope!)
•Refractory period–after you flush the toilet, it won’t flush again for a certain period of time, even if you push the handle repeatedly
•Threshold–you can push the handle a little bit, but it won’t flush until you push the handle past a certain point (this corresponds to the level of
excitatory neurotransmitters that a neuron must absorb before it will fire)
•Resting potential–the toilet is waiting to fire, and the water in the tank represents the overall negative charge inside the neuron waiting for
depolarization
•Action potential–opening the flap in the tank and the water rushing through the pipes
9.4 – How Neurotransmitters Influence Us
Agonistis vs. Antagonists
10.1 – The Nervous System
The Nervous System
Peripheral Nervous System (PNS)
Somatic Nervous System: The division of the peripheral nervous system that controls the body’s skeletal muscles.
Autonomic Nervous System: Part of the PNS that controls the glands and other muscles, such as the heart.
Autonomic Nervous System (ANS)
Sympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations (fight-or-flight).
Parasympathetic Nervous System: Division of the ANS that calms the body, conserving its energy (rest and digest).
In everyday situations, these two systems work together to keep you in a steady internal state.
Central Nervous System
The brain’s neurons cluster into neural networks.
Neurons networked with each other can have short, fast connections. Learning occurs as feedback strengthens connections.
A grain-of-sand-sized speck of your brain contains some 100,000 neurons and 1 billion “talking” synapses!
10.2 – The Endocrine System
The Endocrine System
The endocrine system is the body’s “slow” chemical communication system.
Communication is carried out by hormones synthesized by a set of glands.
Hormones
Hormones are chemicals synthesized by the endocrine glands that are secreted in the bloodstream. Hormones affect the brain and many other
tissues of the body.
For example, epinephrine (adrenaline) increases heart rate, blood pressure, blood sugar, and feelings of excitement during emergency situations.
Pituitary Gland
The “master gland” (and is the most influential endocrine gland).
It releases hormones that influence growth and its secretions also influence the release of hormones by other endocrine glands.
11.1 – Tools of Discovery
Brain Scans
EEG: electroencephalogram
CT: computed tomography scan
PET: positron emission tomography scan
MRI: magnetic resonance imaging
fMRI: functional MRI
11.2 – Older Brain Structures
The Brainstem
The brainstem is the oldest part of the brain, beginning where the spinal cord swells and enters the skull.
It is responsible for automatic survival functions.
The medulla [muh-DUL-uh] is the base of the brainstem that controls heartbeat and breathing.
Helpful mnemonic: picture an Olympic athlete wearing gold medals around her neck and covering her heart and lungs.
The thalamus [THAL-uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs messages to the sensory areas in
the cortex and transmits replies to the cerebellum and medulla.
Hal & Amos are traffic cops….
Reticular formation is a nerve network in the brainstem that plays an important role in controlling arousal.
Cerebellum
The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance.
11.3 – The Limbic System
The Limbic System
The limbic system is a doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions
such as fear, aggression and drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus.
The amygdala[ah-MIG-dah-la] consists of two lima bean-sized neural clusters linked to the emotions of fear and anger.
The hypothalamus directs several maintenance activities like eating, drinking, body temperature, and control of emotions. It helps govern the
endocrine system via the pituitary gland.
Picture a HYPOdermic needle spraying two thirsty llamas with water to quench their thirst and cool them down.
12.1 – Cerebral Cortex Regions
The Cerebral Cortex
The cerebral cortex is the intricate fabric of interconnected neural cells that covers the cerebral hemispheres.
It is the body’s ultimate control and information processing center.
Imagine a Texas hat on your head which is covering the outermost part of your brain –
Each brain hemisphere is divided into four lobes that are separated by prominent fissures. These lobes are the:
frontal lobe(forehead),
parietal lobe(top to rear head),
occipital lobe(back of head),
temporal lobe(side of head).
The frontal lobe is where complex thinking occurs.
Use “front door” as your mnemonic. Put the front door on your forehead and put Einstein (complex thinker) behind the door.
The temporal lobe is where auditory processing occurs.
Use “tempo” as your mnemonic and picture a metronome above your ear (where the temporal lobe is located)
The parietal lobe processes sensory information.
Use a “piranha” fish as your mnemonic. The piranha bites you on the top of the head (where the parietal lobe is located). That’s a sensation the
parietal lobe would process!
The occipital lobe processes visual information.
Use the “Occ” part of the word Occipital and imagine an octopus. Then, picture eyeballs instead of suckers on the tentacles.
12.1 – Functions of the Cortex
Functions of the Cortex
The motor cortex is the area at the rear of the frontal lobes that control voluntary movements.
The sensory cortex (parietal cortex) receives information from skin surface and sense organs.
Association Areas
•A 19thcentury American railroad construction foreman
•In 1848, survived of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal
lobe
•The first case suggesting that damage to specific regions of the brain might affect personality and behavior.
12.2 – The Brain’s Plasticity
The Brain’s Plasticity
Plasticity refers to the brain’s ability to modify itself after some types of injury or illness.
Neurogenesis, the formation of new neurons, has been found in adult mice, birds, monkeys, and humans
13.1 – Our Divided Brain
Corpus Callosum
The Corpus Callosum connects the two hemispheres.
corPLUS calloSUM
The two hemispheres of the brain communicate through the Corpus Callosum.
Picture “corpus CALL SOMEONE”
Splitting the Brain
A procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers -mainly those of the corpus callosum.
Split-Brain Patients
With the corpus callosum severed, objects (apple) presented in the right visual field can be named.
Objects (pencil) in the left visual field cannot.
Divided Consciousness
Right-Left Differences
In an intact brain, each hemisphere does specialize in different functions, but the idea of being “right-brained” or “left-brained” is a myth.
13.2 – The Biology of Consciousness
Cognitive Neuroscience
•Cognitive neuroscience is the interdisciplinary study of brain activity linked with our mental processes
•Recent research has revealed much of our brain work occurs unconsciously, at the same time as conscious processing. This is known as dual
processing.
14.1 – Genes and Behavior Genetics
Behavior Genetics: Predicting Individual Differences
Behavior genetics is the study of our differences and the relative effects of heredity and environment.
Genes: Our Codes for Life
Segments within DNA consist of genes that make proteins to determine our development.
Genome
Genome-the common sequence within human DNA. It is this shared genetic profile that makes us humans, rather than chimpanzees or tulips
The Human Genome Project (an international 13-year effort) was completed in 2003. The project’s goals were to determine the complete
sequence of the 3 billion DNA sub-units, identify all human genes, and make them accessible for further biological study.
Twin and Adoption Studies
Separated Twins
A number of studies compared identical twins reared separately from birth, or close thereafter, and found numerous similarities.
Biological vs. Adoptive Relatives
Adoption studies suggest that adoptees (who may be biologically unrelated) tend to be different from their adoptive parents and siblings.
14.2 – Molecular Genetics
Molecular Genetics
•Molecular genetics studies the molecular structure and function of genes
•Find the genes that together orchestrate traits or reveal at-risk populations for diseases
14.3 – Heritability
Heritability
Heritability is the extent to which variation among individuals can be attributed to their differing genes.
Heritability focuses on the differences between multiple organisms for a single trait. It is a description of a certain population -not an
individual.
14.4 – Gene-Environment Interaction
Gene-Environment Interaction
Genes can influence traits which affect responses, and environment can affect gene activity.
A genetic predisposition that makes a child restless and hyperactive evokes an angry response from his parents. A stressful environment can
trigger genes to manufacture neurotransmitters leading to depression.
Epigenetics
Epigenetics studies the molecular mechanisms by which environmental triggers can switch genes on or off.
15.1 – Natural Selection and Adaptation
Natural Selection and Adaptation
Animal breeding experiments demonstrate the power of genetic selection
In humans, genes endow us with a capacity to adapt
Genes & experience together wire the human brain
Evolutionary Psychology
Evolutionary psychology studies why we as humans are alike.
In particular, it studies the evolution of behavior and mind using principles of natural selection. Traits that contribute to reproduction and
survival are more likely to be passed on.
15.2 – An Evolutionary Explanation of Human Sexuality
Gender Differences in Sexuality
Males and females, to a large extent, behave and think similarly.
Differences in sexes arise in regards to reproductive behaviors.
Natural Selection and Mating Preferences
Natural selection has caused males to send their genes into the future by mating with multiple females since males have lower costs involved.
However, females select one mature and caring male because of the higher costs involved with pregnancy and nursing.
15.3 – Key Criticism of the Evolutionary Perspective
Critiquing the Evolutionary Perspective
Evolutionary psychologists take a behavior and work backward to explain it in terms of natural selection.
Evolutionary psychology proposes genetic determinism and undercuts morality in establishing society.
Where genders are unequal, gender preferences are wide, but when they are closely equal, preferences narrow down.
Evolutionary Psychologists Reply
Evolutionary psychologists argue that we need to test behaviors that expound evolutionary principles.
Evolutionary psychologists remind us how we have adapted, but do not dictate how we ought to be.
Males and females are more alike than different, and if we study these differences we can establish their causes.
15.4 – Reflections on Nature and Nurture
Nature and Nurture
Genes form us.
Experiences form us.
“We are both the creatures and creators of our worlds.”
Biopsychosocial Approach
1
5-3