Psych 2210 Exam 1

The mind-brain problem and monism and dualism

• mind-brain problem: Does the mind control the brain? Does the brain control the mind? Are they the same?

• monism is the idea that the mind and body consist of the same material

• dualism is the idea that the mind and body are separate

The early prescientific individuals who developed ideas about how nerves worked

• Descartes believed that behavior was controlled by animal spirits flowing through the nerves, relied on a small amount of anatomical knowledge and a lot of speculation

• Luigi Galvani was an Italian physicist who, in the 1780s, demonstrated the connection between electricity and nerves by using electricity to stimulate the nerves in the legs of frogs

• Gustav Fritsch and Eduard Hitzig stimulated certain brain regions in dogs to produce movement in certain muscles. Their work was later used to support the idea of localization

• Hermann von Helmholtz demonstrated that nerves do not behave like wires

The difference between localization and equipotentiality. Why are they both inaccurate?

• localization: the idea that specific areas of the brain carry out specific functions

• Equipotentiality: idea that brain can function as an undifferentiated whole

• these are the 2 extremes

The nature vs. nurture debate

• nature vs. nurture debate: ongoing debate about how important heredity is relative to environmental influences in shaping behavior

The terms associated with this debate and genetics

• Natural selection: those whose genes endow them with more adaptive traits are more likely to survive and reproduce

• Heritability: percentage of the variation in a characteristic attributed to genetic factors

• Vulnerability: genes contribute to predisposition for a disorder

What epigenetics is

• epigenetics: an emerging area of scientific research that shows how environmental influences – children’s experiences – actually affect the expression of their genes

The structure and parts of a neuron, The function of the different parts of a neuron

• Dendrites: extensions that receive information from other cells

• Soma: cell body

  • Cell membrane: bilipid layer with proteins “floating” within

• Axon hillock: generates impulse

• Myelin sheath: increases speed of the signals

• Axon: transfers signals

• Terminals: form junctions with other cells; contain neurotransmitters

The different types of neurons and the key differences between them - Where are they found? Where do they send information? What is the polarity?

• Motor neurons: carry commands to the muscles and other organs

  • Brain → body

  • Found mainly within the CNS

  • Multipolar

• Sensory neurons: carry information from the body and external world

  • Body → brain

  • Found mainly within the PNS

  • Unipolar, bipolar

• Interneurons: connect one neuron to another within CNS

  • Multipolar

  • Short or no axon

  • Communicates locally

The basic structure of the cell membrane

• lipid molecules with hydrophilic heads and hydrophobic tails, heads oriented toward the liquid, forming a double layer membrane

Resting potential - What is it? What is its actual voltage? How is it maintained? Hint: know what passive transport and active transport are and know the examples of both

• Resting potential: the difference in charge between inside and outside of the membrane of a neuron at rest (usually -70 mV)

  • Resting potential is as a result of unequal distribution of electrical charges on extracellular (outside of the cell) and intracellular (inside) fluid

  • The cell is “polarized”

• Resting potential is maintained by passive transport and active transport

• Passive transport can move ions when the voltage-gated channels are not active (short-term)

  • Concentration gradient (force of diffusion): high concentration to low

  • Electrostatic pressure: ions repelled from the side with similar charges; want to move toward the opposite charge

• Active transport (long-term)

  • Sodium-potassium pump: uses ATP, pumps 3 Na+ out and 2 K+ in, uses 40% of the cell’s energy to keep the cell negatively charged at rest

Ion channels, selective permeability

• Ion channels: proteins in cell wall; pore in the center allows ions to enter and leave the cell

• Selective permeability: some small molecules can pass through the membrane, larger molecules only pass through protein channels

Action potential - What is an action potential? Is it hyperpolarization, polarization, or depolarization? What does an action potential cause a neuron to do? What is the all-or-none law?

• Action potential: abrupt depolarization of the membrane that allows the neuron to communicate over long distances

• all-or-none: If local threshold (by a stimulus) can reach a certain threshold, action potential is initiated

  • The neuron will either fire or not fire, and will stay intense and strong the entire duration of its firing

Glial cells - What are the four types of glial cells? Which are in the CNS? Which are in the PNS? What are their functions? Why is myelin important? What happens if we don’t have myelin? What is saltatory conduction?

• Glial cells: nonneural cells that provide a number of supportive functions to neurons

  • Schwann cells: produce myelin in PNS, 1 cell wraps single internode

  • Oligodendrocytes: produce myelin in CNS, 1 cell can wrap multiple internodes

  • Astrocytes: support/form blood-brain barrier, insulate neurons, structural support, etc.

    • Compose 20-50% of brain volume

    • Arise from radial glia

    • in CNS

  • Microglia: mediate immune responses in the nervous system, engulf damaged tissue and invading organisms (in CNS)

• Myelin: fatty tissue that wraps around axon to insulate it, makes up myelin sheath

  • no myelin → nerve impulses can’t travel as quickly → diseases like multiple sclerosis

• Saltatory conduction: a form of transmission in which action potentials appear to jump from node to node

Neural communication

• Understand how vesicles release neurotransmitter from the presynaptic neuron in a stepwise fashion. Hint: look at the slide I showed you

  • Action potential arrives at terminal buttons

  • Opening of Ca2+ channels

  • Ca2+ enters

  • Vesicles move to presynaptic membrane

  • Fusion of vesicles

  • Neurotransmitter release

• Know the difference between excitatory postsynaptic potentials and inhibitory postsynaptic potentials

  • Excitatory postsynaptic potential (EPSP): when receptors open sodium channels to produce a partial depolarization of the dendrites and cell body

    • Partial depolarization - more likely to produce action potential

  • Inhibitory postsynaptic potential (IPSP): when receptors open potassium channels, chloride channels, or both to produce a hyperpolarization of the dendrites and cell body

    • Hyperpolarization - less likely to produce action potential

• Know the two main types of receptors

  • Ionotropic receptors

    • Ligand-gated ion channels

    • Binding of neurotransmitter to receptor directly opens or closes an ion channel

    • Local, fast, short

  • Metabotropic receptors

    • Ligand-activated proteins and enzymes “second messengers”

    • Binding to receptors activates g-protein

    • Distant, slow, long

• You should be able to recall all of the ways excess neurotransmitter is taken up from the synaptic cleft

  • Broken down by enzymes

  • Absorbed by glial cells (astrocytes)

  • Diffuse away

• Know what each of the neurotransmitters we talked about does (and what the main inhibitory and exhibitory neurotransmitters are)

  • Acetylcholine

    • Between nerves and muscles (movement)

    • Nerves communicate with muscles by releasing acetylcholine

    • ACh release → muscle contraction

    • ACh inhibition → muscle relaxation

    • Involved in learning

    • Memory - death of ACh neurons in Alzheimer’s disease

  • Amino acids

    • GABA

      • Main inhibitory neurotransmitter

      • Anti-anxiety drugs (e.g., valium) and alcohol act to enhance GABA

      • Deficiency in GABA can cause epilepsy

    • Glutamate

      • Main excitatory neurotransmitter

      • Involved in learning and memory - lots of glutamate in cerebral cortex

  • Monoamines

    • Serotonin: involved in mood, sleep and arousal, aggression, depression, OCD, and alcoholism

    • Dopamine

      • Movement (death of DA neurons impairs movement; Parkinson’s disease)

      • Promotes reinforcing effects of food, sex, and abused drugs

      • Motivation

      • Schizophrenia (blocking DA receptors improves psychological disturbance)

    • Norepinephrine: released during stress, increase arousal and promote sleep/waking cycle, related to depression

    • Epinephrine (adrenaline): stress hormone from adrenal glands (e.g., making heart beat faster), minor role in the brain

  • Neuropeptides

    • Endorphins/enkephalins: block pain, produce pleasure (heroin, morphine); placebo, acupuncture effects

      • Placebo can cause increase in enkephalin release/transmission

    • Substance P: transmission of pain information

    • Neuropeptide Y: initiates eating and produces metabolic shifts

• You should understand basic pharmacological terms (e.g. agonist, direct agonist, indirect agonist, antagonist).

  • Direct agonist: binds and mimics effect of transmitter (has efficacy: ability to produce a desired or intended result)

    • Affinity and efficacy

    • e.g., LSD (serotonin receptors)

  • Indirect agonist: increase neurotransmitters via a mechanism other than receptor interaction - changes could be in synthesis, storage, release, reuptake, or degradation stage

    • Efficacy, no affinity

    • In both direct and indirect agonists, the number of target chemicals increase

  • Antagonist: binds and does not have an effect; thus, prevents transmitter action

    • Affinity, no efficacy

    • e.g., histamine blockers (anti-histamines)

    • Blockers

Know the basic divisions of the central nervous system (brain and spinal cord) and the peripheral nervous system (autonomic [sympathetic and parasympathetic] and somatic).

• central nervous system (CNS): brain and spinal cord

• peripheral nervous system (PNS): all nerves and sensory structures outside of the brain and spinal cord

  • Somatic nervous system: voluntary control of skeletal muscle, movements, and reflex arcs; connecting brain to the body

  • Autonomic nervous system: involuntary control of glands and smooth muscle; heartbeat, blood flow, breathing, body temperature, etc.

    • Sympathetic nervous system: arousing; fight or flight

      • Increases heart rate, respiration, perspiration, glucose

      • Decreases digestion

    • Parasympathetic nervous system: calming; rest and digest

      • Controls organs when body is relaxed

      • Decreases heart rate, respiration

      • Increases blood flow, digestion

Understand the basic concept of neurulation and the neural plate forming the neural tube

• Neurulation: neural plate folds into the neural tube

  • Driven by sonic hedgehog protein (SHH)

  • Neural plate has 3 layers

    • ***Ectoderm → skin and CNS

  • Neural tube develops into brain and spinal cord

You need to know and understand the stages that occur after neurulation (e.g. proliferation, migration, circuit formation, circuit pruning, myelination)

• Proliferation: division and multiplication of cells

• Migration: move through radial glial cells to their final destination

• Circuit formation: form functional connections with others

• Circuit pruning: elimination of excess neurons and synapses

• Myelination

Understand CNS vs. PNS terminology (Ganglion vs nucleus, nerve vs tract)

Know your directional terms

• Dorsal: toward the back, ventral: toward the stomach (used more for animals)

• Anterior: toward the front, posterior: toward the rear

• Medial: toward the middle, lateral: toward the side

• Superior: above another structure, inferior: below another structure

Know terms for brain sections/planes (Coronal, sagittal, horizontal)

Know the parts that make up the forebrain, midbrain, and hindbrain

• Forebrain: know the parts of the limbic system and what they do

  • Amygdala: emotional behavior and expression

  • Hippocampus: learning and memory, neurogenesis, short-term memory → long-term memory

  • Basal ganglia: regulates the activity of cerebral cortex neurons

    • Involved in coordination of movement

  • Hypothalamus: controls autonomic nervous system and primitive behaviors

  • Thalamus: receives/relays sensory information

• Forebrain: be able to name the lobes of the brain and be able to name the main structures we talked about in each lobe (e.g., central sulcus, primary motor cortex, Broca’s area, etc.)

  • Frontal lobe

    • Prefrontal cortex: higher cognitive functions, behavioral control, emotions, impulsivity

    • Broca’s area: speech and language (production)

    • Primary motor cortex (precentral gyrus): planning and execution of intentional movement

    • Damage might affect impulses, language, social behavior, some voluntary movement

  • Parietal lobe: integrate sensory information from body

    • Primary somatosensory cortex (postcentral gyrus): processes touch, pain, temperature, etc.

    • Mapped similar to motor cortex

    • Damage might affect ability to recognize or locate body parts and sensation

  • Occipital lobe: contains areas that are involved in processing colors and shapes

    • Visual cortex: receives and processes visual information

    • Damage might cause problems with visual field defects and distorted perception

  • Temporal lobe: various aspects of memory

    • Auditory cortex: recognizing and processing sound

    • Wernicke’s area: speech comprehension

    • Damage might cause problems with hearing, understanding, and producing language, and the ability to recognize familiar objects or faces

• Midbrain: there is only one slide on the midbrain so know these parts. Most importantly, understand why the substantia nigra is important. Hint: Parkinson’s disease

  • Structures have secondary roles in vision and hearing

  • Superior/inferior colliculi

  • Substantia nigra: roles in movement, dopamine-related

  • Ventral tegmental area: reward

• Hindbrain: There is also only one slide on this. Know these parts and their functions

  • Pons: sleep, arousal, reflexes, respiration

    • Reticular formation: collection of nuclei that play a role in respiration, reflexes, posture, balance, sleep, etc.

  • Medulla: control of essential life processes like respiration

  • Cerebellum: movement refinement, balance, posture, motor learning

Spinal cord

• Understand the basics of a reflex circuit

  • reflex circuit: a neural pathway that controls a reflex

• Know the function of gray and white matter in the spinal cord

  • Gray matter is made up of sensory and motor nuclei (group of neurons). White matter is largely longitudinal myelinated axons carrying information to and from brain (tracts). Gray matter acts as the processing center, receiving sensory information, integrating it, and sending out motor commands by containing the cell bodies responsible for relaying signals between the body and the brain, essentially allowing for reflex actions and basic motor functions to occur; it is where sensory and motor neurons synapse with interneurons to process information before sending signals further up the spinal cord or to muscles.

Ventricles and Dura: Understand what the dura and ventricles do. You don’t need to name each ventricle or each dura layer

• Ventricles: cavities in brain which develop from the hollow interior of the nervous system

  • Filled with cerebrospinal fluid - carries material from blood vessels to the CNS and transports waste materials in the other direction

• Meninges/dura: covering of brain and spinal cord

Blood-brain barrier: Understand what the BBB does and why it is a problem if it is not intact or isn’t working properly

• Blood-brain barrier: between blood and the fluid that surrounds neurons

  • Protects brain from potentially toxic chemicals circulating into blood

Peripheral nervous system

• Know the divisions of the PNS

  • Somatic nervous system

  • Autonomic nervous system

    • Sympathetic nervous system

    • Parasympathetic nervous system

• Know the difference between afferent and efferent. A trick to remember: Afferent arrives (body → CNS), Efferent exits (CNS → body)

  • Afferent nerves (sensory): carry information from the body to the CNS

  • Efferent nerves (motor): carry information from the brain and spinal cord to muscle fibers

Know the difference between a theory and a hypothesis

• Theory: coherent explanation or interpretation of a one or more phenomena based on wide variety of findings

  • Concise, coherent, systematic, applicable

• Hypothesis: proposed explanation for a fairly narrow set of phenomena

  • Based on prior experience, literature, preliminary observation, and logic

“Observation” has a broad definition in science. Know the four types of observation that we discussed.

• Naturalistic observations

• Case studies

• Surveys

• Experiments

What are the downsides of a correlational study?

• Cannot determine cause and effect

• Chance of confounding variables

• Results are valuable but require careful interpretation

What is an independent variable? What is a dependent variable? What is a confounding variable?

• independent variable: the one you manipulate

• dependent variable: the one you measure

• confounding variables: outside variables that could affect results

Know what in vitro, in situ, and in vivo mean

• In vitro: translates directly to “in glass,” meaning the study takes place in a test tube rather than in a model organism

• In vivo: translates directly to “in life,” meaning the study takes place in a living cell or model organism

• In silico: an experiment done in a virtual setting such as a computer or virtual simulation

Know the different types of staining for neurons and know the basic definition of immunostaining

• Staining methods are used to visualize neuron morphology, receptor availability, protein expression

  • Golgi stain: randomly stains neurons

  • Myelin stain: stain myelin to identify pathways

  • Nissl stain: stain cell bodies of neurons

  • Retrograde stain: stain pathways - taken up by cell body to dendrites

• Immunostaining methods: use antibodies attached to a dye to identify cell components

Know what a scanning electron microscope does

• Scanning electron microscope: beam of electrons induces specimen to emit electrons

  • Enhancement of transmission electron technique

  • Magnifies images up to 2-3 million times

  • Produces 3D image

Know the different methods of imaging the brain (e.g. EEG, PET, CT, MRI, fMRI)

• Electroencephalogram (EEG): electronic amplifier detects electrical activity of all neurons between two electrodes (developed by Hans Berger)

  • Cost effective and simple

  • Event-related potential: averaging many recorded responses to stimulus

  • Cancels out background noise

  • Reveals brain’s unique response to stimulus

• Computed tomography (CT): produces series of X-rays then composites them into a 3D image

  • Image shows differing densities of blood vessels in the brain

• Positron emission tomography (PET): observation of brain regions through a radioactive substance injected into bloodstream

  • Scanner picks up emitted positrons to form a color-coded image

  • Indicates relative activity of brain regions

  • Difference scans

  • Cannot detect changes less than 30 seconds in duration

  • Results do not image the brain

• Magnetic resonance imaging (MRI): measures radio-frequency waves emitted by hydrogen atoms exposed to magnetic field

  • Shows structure, not function

  • Most hydrogen atoms within water molecules

  • Diffusion tensor imaging: MRI variant measuring the movement of water molecules

• Functional magnetic resonance imaging (fMRI): detects increases in blood flow and oxygen usage

  • Suitable for repeated measurements

  • Good spatial resolution

  • Alternative to PET scans

  • Costly due to expense of equipment

Know the methods of manipulating brain activity that we discussed and know why they are used (e.g., TMS and DBS)

• Transcranial magnetic stimulation (TMS): a noninvasive technique using a magnet coil to induce a voltage

  • **1 per second or lower decreases brain excitability, while frequencies of 5 seconds or higher increase excitability

  • Device held over scalp and pulsed at varying rates

  • Valuable in both research and therapeutically

  • **Used clinically to treat Parkinson’s disease

  • **Used in research to look at modifications in neural pathways recovered in stroke patients

  • Transcranial direct current stimulation (tDCS): uses electrical stimulation to active astrocytes and increase neuronal excitability and connectivity

• Deep brain stimulation (DBS): implanting electrodes within certain areas of the brain to produce electrical impulses that regulate abnormal impulses

Understand the difference between plagiarism and falsification

• Plagiarism: theft of another’s work or ideas

• Fabrication: faking results

  • More serious than plagiarism

  • Introduces erroneous information to the field

  • 2% of researchers admit to falsification

Be able to identify what informed consent is and why it is important

• Informed consent: individual’s voluntary agreement to participate with understanding of potential adverse effects

Know which committee oversees research with human subjects and which committee oversees research with animals

• Institutional Review Board (IRB) - humans

• Animal Care and Use Committee (ACUC) - animals

Be able to recognize what deception is in research

• Deception: misinforming or failing to disclose to participants the details of the study

  • Many restrictive guidelines on appropriate deception

  • Informed consent required if there is a risk of physical pain or severe emotional distress

Be able to recall the two controversial research studies we watched videos on in class.

• Milgram shock obedience experiment

• Stanford prison experiment