Introduction to Brain and Behavior
Dr. Gina O’Neil-Moffit
Exam 1 Study Guide(Chapters 1-4)
CHAPTER ONE: INTRO AND ORIGINS
• Descartes (Dualism): a nonmaterial mind and a material body both contribute to behavior
o Mind directs rational behavior
o Body and Brain direct behavior via mechanical and physical principles • Mentalism: behavior is a function of the nonmaterial mind
• Materialism (Monism): behavior is a function of the nervous system without the mind
• Aristotle (Psyche): Psyche is a synonym for mind, which was once proposed to be the source of all human behavior
• Darwin (Natural Selection): the way species change (evolve) over time • If a new trait leads to reproductive success and an increase chance in survival then it will be passed on to offspring
• Mendel (Genes): demonstrated inheritance occurs through genes
• Locked-in syndrome: condition where patient is aware and awake but cannot move or communicate due to paralysis of nearly all voluntary muscles
• Biological Psychology: the study of physiological, evolutionary and developmental mechanisms of behavior and experience
• Brain controls behavior
o Body-Mind Problem: how the brain produces both behavior and
consciousness/Mental mind versus physical brain If you want to learn more check out mea 150 class notes
• The CNS cannot work/do much without PNS
• Nervous system is composed of Neurons and Glia
• Animal Behaviors:
• 1. Inherited- relatively fixed behaviors If you want to learn more check out economics uncc
• 2.Learned- flexible behaviors
o Example: crossbill’s inherited behavior of how to eat pinecone seeds vs. roof rat which has to LEARN how to eat pine cone seeds
o Humans: Suckling (inherited) vs. eating later in life (influenced by learning and culture)
• Chromosomes: strands of genes, come in pairs
• DNA: deoxyribonucleic acid, what makes up genes
• RNA: ribonucleic acid, serves as template for the synthesis of proteins • Genes: hold genetic information
• (Homo)zygous: identical pair of genes on both chromosomes(ex: AA, aa) • (Hetero)zygous: unmatched pair of genes on both chromosomes(ex: Aa) • Dominant: strong effect on Homozygous or Heterozygous conditionIf you want to learn more check out What are the 6 functions of protein?
• Recessive: only has effect on homozygous condition
• Sex-linked: gene on a sex chromosome, usually X
• Sex-limited: on any chromosome(autosomal) BUT activated by sex hormones and has effects only in one sex or another
• Mutation: inheritable change in DNA molecule
o Can be detrimental or can be selected for
• Microduplication/Microdeletion: part of chromosome that might appear more than once (duplication) or not at all (deletion)
• Monozygotic twins: from one egg
• Fraternal twins: from 2 eggs
o Twins are used to study heredity and environment
• Heritablity: how much characteristics depend on genetic influences o PKU: the genetic inability to metabolize the amino acid phenoketonuria (environment can modify PKU)
• Epigenetics: study of changes in gene expression without modification of DNA sequence
o Genes and environment interact to shape behavior
• Principle of Proper Mass: species with more complex behaviors will usually posses larger brains If you want to learn more check out What methods can be applied to dispose of under applied or over applied manufacturing overhead?
• Encephalization quotient: ratio of actual to expected brain size according to principle of proper mass for an animal of a particular body size
o Actually better to compare cell counts and packing density
• Central Nervous System (CNS): brain and spinal cord, Peripheral Nervous System (PNS): everything else
CHAPTER 2: NEUROANATOMY
• Neuroplasticity: nervous systems potential for physical or chemical change that enhances its adaptability to environmental change and its ability to compensate for injury
Spinal cord •
Don't forget about the age old question of french 101 study guide
We also discuss several other topics like time spent ensuring that the product is not defective is referred to as
• Somatic Nervous System: carry sensory information from muscles, joints, and skin to CNS. Transmits outgoing motor instructions to produce movement
• Autonomic Nervous System: prepares internal organs for rest and digest response via the parasympathetic (calming) nerves or prepares fight-or-flight response through the sympathetic (arousing) nerves
• Enteric Nervous System: controls the gut. The ENS communicates with the CNS via the ANS but mostly operates autonomously.
• Afferent information is sensory information coming into the CNS o (A=arriving at the CNS)
• Efferent information is information leaving the CNS
o (E=exiting the CNS)
• Anatomical Orientations: (think of activity from class)
o Coronal section= a cut from the top of the head down
o Horizontal section= a cut through the brain from the eyes to the back of the head (think horizon)
o Sagittal section= cut right down the middle
o Dorsal=superior (above/top)
o Ventral/inferior (below/bottom)
o Anterior(front/ex: your belly)
o Posterior(back/ex: your back)
o Lateral(to the side)
• Sections of the Brain: (need to also know where located on brain) o Parietal= sensory integration, tactile functions
o Frontal= motor and executive function
o Temporal = visual, auditory and memory
o Occipital= vision
• Brainstem: medulla, pons, thalamus, hypothalamus and midbrain(responsible for unconscious behavior and greatly preserved in ALL species)
o Begins where spinal cord enters the skull
o Receives afferent nerves coming from senses and sends efferent nerves out to control movements
• Forebrain (prosencephalon, Diencephalon, Telencephalon)
o Diencephalon=thalamus, hypothalamus
▪ Thalamus= Gateway for RELAY OR FILTER of sensory information to the cortex
▪ Hypothalamus= Hormone function, Through connections with the pituitary gland, Feeding, Sexual behavior, Sleeping, Temperature regulation, Emotional behavior
o Telencephalon=cerebral cortex, hippocampus, basal ganglia
▪ Neocortex (cerebral cortex)=Regulates various mental activities,6 layers, constructs and responds to world
▪ Basal ganglia= Control of voluntary movement
• Principal structures: caudate nucleus, putamen, and globus
• Controls voluntary and involuntary movement
• Related disorders: Parkinson’s disease and Tourette’s
▪ Limbic system= Regulates emotions and behaviors that store and require memory
• Group of structures between the neocortex and brainstem
• Principal structures: amygdala, hippocampus, cingulate cortex • Regulation of Emotional (amygdala), Memory and spatial
▪ Olfactory System= the organs responsible for our sense of smell. • Principal structures: pyriform cortex, amygdala,
o Evolutionarily older
o Three or four layers of gray matter
o Controls motivational states and certain forms of memory
• Midbrain (mesencephalon): Tectum, tegmentum, superior and inferior colliculus, substantia nigra
o Tectum (roof of midbrain)
▪ Superior colliculi (vision) and inferior colliculi (hearing)
▪ Produces orienting movements (e.g., turning head to see source of sound)
o Tegmentum (floor of midbrain)
▪ Substantia nigra
▪ Periaqueductal gray (PAG)
• Hindbrain (Rhombencephalon): cerebellum, medulla, pons
o Metencephalon= pons, cerebellum
o Myelincephalon= medulla
o Controls various motor functions ranging from breathing to balance to fine movements
o Integrates both voluntary and involuntary body movement
o Reticular formation: Regulation of sleep–wake behavior and behavioral arousal
o Pons (“bridge”): Connects cerebellum to the rest of the brain
o Medulla: Control of breathing and heart rate
o Cerebellum: Controls complex movements and cognitive functions • Cerebrum: Major structure of the forebrain, consisting of two virtually identical left and right hemispheres
• Cerebellum: Involved in the coordination of motor and possibly other mental processes
• Corpus Callosum: band of white matter that runs much of the length of the cerebral hemispheres, contains about 200 million nerve fibers that join the two hemispheres • Sulcus: indent
o Fissure: deep sulcus
• Gyrus: bump
• Gray Matter: areas of the nervous system predominantly composed of cell bodies and blood vessels
• White Matter: areas of the nervous system predominantly composed of cell bodies and blood vessels (myelinated)
• Meninges: 3 layers of protective tissue, go down spinal cord, has CSF in subarachnoid space
o Dura mater: tough outer layer of fibrous tissue
o Arachnoid layer: thin sheet of delicate connective tissue, blood vessels o Pia mater: moderately tough inner layer that clings to brains surface o Meningitis: Infection of the meninges and cerebrospinal fluid (CSF)
• Stroke: Sudden appearance of neurological symptoms as a result of severe interruption of blood flow(remember impacts opposite side of body that it happens on in the brain)
• Brain Blood Barrier(BBB)
o Keeps out= viruses, bacteria, chemicals, nutrients(active transport to get nutrients in brain)
o Lets through=small uncharged molecules, fat soluble molecules, glucose ▪ Drugs= many illegal and legal drugs are made to penetrate BBB • Ventricles: cavities in the brain that contain cerebrospinal fluid (CSF) o 2 lateral(left and right), third ventricle, fourth ventricle
• Cerebrospinal fluid (CSF): Sodium chloride and other salts, Fills the ventricles and circulates around the CNS in the subarachnoid space (between the arachnoid layer and the pia mater), Cushions the brain, helps brain excrete metabolic wastes • Neurons: main nervous system cells
• Glia: Helper cells
• Lamina: row or layer of cell bodies separated from other cell bodies by a layer of axons and dendrites
• Column: set of cells perpendicular to surface of the cortex, with similar properties • Tract: set of axons within CNS
• Nerve: set of axons in PNS
• Nucleus: cluster of neuron cell bodies within CNS
• Ganglion: cluster of neuron cell bodies in PNS
• Spinal Cord: Controls most body movements, Can act independently of the brain • Cranial Nerves(*memorize)
11. Slot-spinal accessory-M
(some say marry money but my brother says only bad boys marry money)= how to remember sensory/motor/both
o Divided into segments(C,T,L,S, coccygeal)
• Dermatome: area of skin supplied with afferent nerve fibers by a single spinal cord dorsal root
• Bell-Magendie law: sensory info enters cord posteriorly (dorsally); motor info exits cord anteriorly (ventrally)
CHAPTER 3: NERVOUS SYSTEM CELLS
• Camillo Golgi: created dye that stained neurons, and said nervous system is composed of a network of interconnected fibers: a “nerve net.”
• Santiago Ramon y Cajal: illustrated pictures of neurons, discovered nervous system is made of discrete cells, neurons are the units of brain function
• Cells of the Nervous System contain:
• membrane – a structure that separates the inside of the cell from the outside environment.
• nucleus – a structure that contains the chromosomes.
• mitochondrion – structure that performs metabolic activities and provides energy that the cells requires.
• ribosomes – sites at which the cell synthesizes new protein molecules. • endoplasmic reticulum – network of thin tubes that transport newly synthesized proteins to their location.
• Phospholipid bilayer - 2 layers of fat molecules that are free to float around one another(hydrophilic head, hydrophobic tail)
• Soma=core/cell body
• Dendrites=branching extensions, collect information from other cells • Axon=main root, carries messages to other neurons
• Dendritic spines= Protrusion from a dendrite that greatly increases its surface area and is the usual point of contact with axons of other cells
• Axon hillock=Juncture of soma and axon, where the action potential begins • Terminal button=Knob at the tip of an axon that conveys information to other neurons; also called an end foot
• Synapse=Gap between one neuron and another neuron,Usually between an end foot of the axon of one neuron and a dendritic spine of another neuron
• Presynaptic Terminal: end point of an axon where the release of chemicals occurs to facilitate communication with other nearby neurons
• Postsynaptic Terminal: one that receives a chemical transmission from a nearby neuron
• Information flow (always this direction): dendrite-cell body-axon-terminal • Sensory neurons=carry information from the sensory receptors in or on the body to the spinal cord
o sensory neuron is specialized at one end to be highly sensitive to a particular type of stimulation (touch, light, sound, etc.)
• Interneurons (association neurons)=associate sensory and motor activity within the central nervous system.
• Motor neurons=send signals from the brain and spinal cord to muscles o motor neuron has its soma in the spinal cord and receives excitation from other neurons and conducts impulses along it axon to a muscle
• Language: Excitation and Inhibition
• Each neuron receives thousands of excitatory and inhibitory signals every second
• Neurons sum these signals and respond accordingly, becoming active or not. • From the simple yes-no language of neurons emerge enormous possibilities for behavior.
• Glial Cells:
• Structural support for neurons
• Transports substances between neurons and capillaries (blood–brain barrier)
• Scar tissue formation
o Ependymal cells
• Found in the walls of the ventricles; make and secrete cerebrospinal fluid (CSF)
o Oligodendroglial cell (CNS myelin)
• Glial cell in the central nervous system that myelinates axons
o Schwann cell (PNS myelin)
• Glial cell in the peripheral nervous system that myelinates axons o Microglia (phagocytosis scavenging of debris)
• Microglia monitor the health of brain tissue and play the role of its immune system.
• They identify and attack foreign tissue.
• When brain cells are damaged, microglia invade the area to provide growth factors that aid in repair.
• DNA-(transcription)->mRNA-(translation)->Amino acid chain
• A protein’s shape and its ability to change shape and to combine with other proteins are central to its function
o Proteins are necklaces of amino acids (long chain molecules.) Proteins are the basis of how biology gets things done.
o As enzymes, they are the driving force behind all of the biochemical reactions which make biology work.
o As structural elements, they are the main constituent of our bones, muscles, hair, skin and blood vessels.
o As antibodies, they recognize invading elements and allow the immune system to get rid of the unwanted invaders.
o Some proteins change shape when other chemicals bind to them; others, in response to changes in electrical charge.
o The protein molecule’s ability to change shape is analogous to a lock in a door.
• Golgi apparatus wraps proteins in a membrane and sent to where it needs to go in the cell, or outside the cell
• Cell Membrane:
o Phospholipid bilayer=2 layers of fat molecules that are free to float around one another (hydrophilic (phosphate) head and hydrophobic (fatty acid) tail) o Semipermeable: water, Oxygen and CO2 move freely, charged ions move through ion channels
• Channel=Opening in a protein embedded in the cell membrane that allows the passage of ions
• Gate=Protein embedded in a cell membrane that allows substances to pass only when open
• Pump=Protein embedded in a cell membrane that actively transports a substance across the membrane
• Genes -> proteins -> cells -> behavior
• Genotype: genetic makeup
• Phenotype: physical and behavioral traits
• Nucleus of each human somatic cell contains 23 pairs of chromosomes, or 46 in all.
• One member of each pair of chromosomes comes from the mother, and the other member comes from the father.
• The chromosome pairs are numbered 1 to 23.
• Chromosomes 1-22 are autosomal, they contain the genes that contribute most to our physical appearance and behavioral functions.
• Pair 23 are sex chromosomes, they contribute to our physical and behavioral sexual characteristics
• Allele: a cell has 2 copies of every gene(one from mother, one from father) and matching copies are alleles
• Epigenetics: the environment can allow a gene to be expressed or inhibit its expression
o Epigenetic Mechanisms influence protein production:
▪ Blocking a gene so it cant be transcribed
▪ Unlocking a gene so it can be transcribed
CHAPTER 4: THE NERVE IMPULSE
• Galvani (18th century): Electrical current applied to a dissected nerve induced a twitch in the muscle connected to the nerve; Galvani concluded that electricity flows along the nerve
• Bartholow (1874): Patient brain stimulation
• von Helmholtz (19th century): Flow of information in the nervous system is too slow to be exclusively electricity
o Nerve conduction: 30-40 meters a second
o Electricity 3 x 108 meters/second
• Bernstein (1886): It is not the ions themselves that travel along the axon but rather a wave of charge
• Hodgkin and Huxley (1930-1940): Used Giant squid Axon(on a neuron) which has a much large diameter than a human axon, they received a Nobel Prize • Electricity =A flow of electrons from a body that contains a higher charge (more electrons) to a body that contains a lower charge (fewer electrons) • Negative pole=The source of electrons; higher charge
• Positive pole=Location to which electrons flow; lower charge
• Electrical Potential: The difference in charge between the negative pole and the positive pole
• Concentration gradient=Ions flow from areas of high concentration to low concentration
• Voltage gradient=Ions flow to areas of opposite charge
o negative to positive, positive to negative
o opposite charges attract, similar charges repel
• Diffusion to reach equilibrium= movement of ions from an area of higher concentration to an area of lower concentration through random motion • Cations= + charge ions
• Anions= - charge ions
• The membrane of a NERVE cell maintains an electrical polarization • In cells, there are ions inside and outside the cell, which are NOT equally distributed. Due to this, the charge on the inside of the cell is different from the charge outside the cell this is known as a concentration gradient.
o The cell is polarized: at rest, an electrical gradient is maintained across the plasma membrane (negative charge is greater inside the cell)
o The cell has a resting potential: difference in voltage across the membrane of a cell (~ -70 mV) a rest(potential: the ability to use stored power, the charge is a store of potential energy)
• -70 mV is the RESTING potential.
o Less negative than -70 is DEPOLARIZED (influx of sodium ions) o More negative than -70 is HYPERPOLARIZED (can occur with efflux of K+ or influx of Cl-)
• Selective permeability of the membrane: some molecules pass more freely across the membrane than do other molecules; controlled by “channels”
o At rest:
▪ H2O, CO2, O2 pass freely
▪ K+ and Cl- ions pass slowly (not quite closed)
▪ Na+ channels are closed*
▪ Na+/K+ pump
o *certain types of stimulation cause the Na+ channels to open • A sodium/potassium pump acts to maintain proper concentrations of Na+ and K+. o Needed for maintaining resting potential and for recovery from an action potential.
o 3 Na+ out for every 2 K+ in, so more positive on outside
• ION MOVEMENT is the ACTION POTENTIAL!
• Action potential=Large, brief reversal in polarity of an axon
o Lasts approximately 1 millisecond (ms)
• Threshold=Voltage on a neural membrane at which an action potential is triggered o Opening of Na+ and K+ voltage-sensitive channels
o Approximately −40 mV relative to extracellular surround
• Voltage-gated ion channels: Protein channel that opens or closes only at specific membrane voltages
o Sodium (Na+) and potassium (K+)
o Closed at membrane’s resting potential
o Na+ channels are more sensitive than K+ channels and therefore open sooner • Absolute refractory period: A new action potential cannot (usually) be elicited • Relative refractory period: In the later phase of an action potential, during which stronger electrical current is required to produce an AP
• Nerve Impulse: Propagation of an action potential on the membrane of an axon o Refractory periods produce a single discrete impulse that travels along the axon in one direction only.
o Size and shape of action potential remain constant along the axon o All-or-none law:
• Although an action potential could travel in either direction on an axon, refractory periods prevent it from reversing direction
• Myelin: Produced by oligodendrocytes in the CNS and Schwann cells in the PNS o Speeds up neural impulse
o If myelin is damaged, a neuron may be unable to send any messages over its axons.
o In multiple sclerosis (MS), the myelin formed by oligodendroglia is damaged, which disrupts the functioning of neurons whose axons it encases
• Node of Ranvier: Part of an axon not covered by myelin
o Tiny gaps in the myelin sheath
o Enables saltatory conduction
• Saltatory conduction: Propagation of an action potential at successive nodes of Ranvier
o Saltare: to dance (Latin)
• Nerve impulses traveling from other neurons bombard the receiving neuron with all manner of inputs, excitatory and inhibitory.
• The cell body, which lies between the dendritic tree and its axon, can receive inputs from many other neurons.
• Ligand-gated ion channels: At synapses,Open when a ligand (neurotransmitter) binds,Allow ions thru, may also start biochemical cascade within cell • Excitatory postsynaptic potential (EPSP): Brief depolarization of a neuron membrane in response to stimulation
o Depolarized neuron is more likely to produce an action potential. o EPSPs increase the number of action potentials above the spontaneous firing rate
o Associated with opening of Na(sodium) channels, allows Na+ influx
• Inhibitory postsynaptic potential (IPSP):Brief hyperpolarization of a neuron membrane in response to stimulation
o Hyperpolarized neuron is less likely to produce an action potential. o IPSPs decrease the number of action potentials below the spontaneous firing rate
o Associated with opening of potassium channels(efflux of K+) or opening of chloride channels(influx of Cl-)
• The spontaneous firing rate refers to the periodic production of action potentials despite synaptic input.
• Temporal summation: Pulses that occur at approximately the same time on a membrane are summed.
o Repeated stimuli can have a cumulative effect and can produce a nerve impulse when a single stimuli is too weak.
• Spatial summation: Pulses that occur at approximately the same place on a membrane are summed.
o Synaptic input from several locations can have a cumulative effect and trigger a nerve impulse.
• The axon hillock is the junction of soma and axon
o Rich in voltage-gated channels
o Where EPSPs and IPSPs are integrated
o Where action potentials are initiated
• Synaptic Potential: EPSPs and IPSPs on the dendrites and soma, If membrane reaches threshold at the axon hillock: an action potential is initiated, it travels down the axon membrane
• Whether cell “fires” an Action Potential depends on the balance of E and I inputs: the sum of E and I must reach threshold at the axon hillock
1. A neurotransmitter is released from a neuron terminal into a synapse 2. The neurotransmitter binds to a receptor/channel in the postsynaptic cell 3. The neurotransmitter opens that ligand-gated channel
4. The channel lets ions into the cell
5. The ions slightly change the charge of the cell
6. If enough positive ions enter the cell, the cell’s charge is sufficiently changed, and there is an action potential which opens voltage-dependent channels and propagates down the axon
• We receive information about the world through: (Light Touch Example) o somatosensation = touch, temp, pain
o audition = hearing
o vision = sight
o gustation and olfaction = taste and smell (chemosenses)
o proprioception = body position and movement
• Neurons related to these diverse receptors all have ion channels on their cell membranes.
• These ion channels initiate the chain of events that produces a nerve impulse.
• Movement and Action Potentials:
o Spinal motor neurons send nerve impulses to synapses on muscle cells. o Axon of each motor neuron makes one or more synapses with target muscle. o End plate
▪ Part of the muscle membrane that is contacted by the axon terminal o Acetylcholine (ACh) works at ligand-gated channels to allow Na+ and K+ ions in to depolarize the cell.