AP PSYCH Unit 1: 1.1-1.3

1.1 Interaction of Heredity and Environment

Video 1 -  Nature & Nurture, Epigenetics

• What influences your personality, preference, intelligence, etc.?

Nature: 

• Genetics, the genetic factor that distinguishes humans from animals (that makes language)

Nurture:

•  Everything else! John B. Watson, able to “train anyone into any type of specialist”

Work together!

• At conception, genetics determine

  • Eye/hair color, body shape, sex, temperament

• Experience and environmental influence

  • Culture, social groups, etc

Epigenetics 

• Mother rats pass on “love licking” behavior to kids

  • Eventually altered their DNA

• Nature & nurture work together to influence human development

• Epigenetic research helps us see the amazing impact NURTURE has on NATURE

Video 2 -  Twin Studies

Identical twins

• Same DNA, both are the same sex, one egg (monozygotic)

• Raised in separate environments  → similarities due to genetics 

• “Jim Twins”

  • Completely different environments but many similar experiences and traits

Heritability, how much can we attribute their differences and their similarities to genetics (nature.)

Fraternal Twins

• Different DNA, as genetically similar as non-twin siblings, opposite sex?

• -Raised in the same environment → similarities due to environment

• Twin studies can involve identical twins as well as fraternal twins

• (adoption, family, and DNA) all help us determine the influences of nature and nurture on our behaviors and mental processes

• Twin studies help determine the influences of genetic factors on personality traits, (intelligence)

1.2 Overview of the Nervous System

Video 1 - Divisions of the Nervous System

Nervous System

• Peripheral NS

  • Carry info from all over to CNS & from CNS

    • Ganglion, Nerve

  • Somatic NS 

    • Bring in sensory information from the CNS out to various glands and muscles

  • Autonomic NS 

    • Heart rate, blood pressure, breathing, digestion

    • Sympathetic (fight or flight)

      • Bear scenario- scary and need to get away

    • Parasympathetic (rest and digest)

      • Parachute → rest, etc. Calm homeostatic state

• Central NS (brain and spinal cord)

  • Encased in bone (VERY important)

• The human nervous system consists of several divisions and each division has its own specialized functions

1.3 The Neuron and Neural Firing

Video 1 - Types of Neurons and Helpers

Myths:

• People are right-brained or left-brained

• You can’t grow new neurons

• Only use 10% of our brain ….. Still a myth, but interesting story

Neurons

• Lead singers and back-up vocals

• Neurons & Glial Cells communicate

  • Ex: 90 billion neurons and 900 billion Glial Cells

    • Only use neurons, we only use 10% picked up from electrical signals 

  • Glia used to be thought of as just “helpers”

    • They do a lot more

    • Send and receive chemical signals to and from each other and to and from neurons, along with other cells. Does not communicate with electricity

What info?

• Thoughts, understanding, inspiration, insight (all cognitive)

• Limit discussion to things easily measured

  • How loud → sensory neuron, 

    • receive raw material from the body’s sense organs like free nerve endings in the epidermis

  • How much a muscle flinches → motor neuron

    • Are connected to muscle fibers and can make the muscle contract

Spinal Reflex Arc

• The receptor site is in the peripheral nervous system

  • Receive a sensation in the spinal cord

  • Sensory neuron connects to motor neurons with an interneuron

• Takes information from sensory neuron (receptor), talks to interneuron that talks to motor neuron, sending information “screaming” to the muscles

  • Measure how loud and how quick the reflex is

Not the S.A.M.E → Sensory Afferent, Motor Efferent

Video 2 - Basic Anatomy of the Neuron

Neuron

• Estimated 80 billion

• Building blocks of the nervous system, allow all communication in the nervous system

• Several different types, some of which have great specificity (ex, feature detector cells)

• Jobs

  • Receive messages from other neurons

  • Carry message down axon

  • Send messages to other neurons

• Cells fire in a particular pattern, which results in thoughts

Structure 

• Dendrites

  • Detect and receive messages, then pass them along the neuron

• Soma

  • Protects and keeps major parts of the interior and nucleus healthy

• Axon

  • Sends an electrical impulse, or action potential down

  • Some axons are protected by a myelin sheath

• Myelin Sheath

  • Fatty substance encasing most neurons in the brain

  • Protects and insulates the axon, speeding up the transmission of nerve impulses

  • Deterioration of myelin results in multiple sclerosis

• Terminal Buttons

  • Allow communication with other dendrites

• Synapse / Synaptic Gap

  • After each terminal button, there is a synapse / synaptic gap

  • Neurotransmitters cross this gap and lock into the dendrite of the postsynaptic neuron

  • If enough neurotransmitters lock into the postsynaptic neuron’s dendrites, that neuron will fire

DSATs

• The message starts at the Dendrite,

• then goes to the Soma, 

• Axon, 

• then the Terminal Button, 

• and synapse

Video 3 - Neural Firing

Summary of Neural Firing

• Neurons fire when there is a shift in electrical energy → creating an action potential

• When the action potential reaches terminal buttons, neurotransmitters are released into the synapse

• Neurotransmitters lock into the dendrites of the next neuron

• Some neurotransmitters are excitatory, other inhibitory

  • Excitatory → next neuron more likely to fire

  • Inhibitory → next neuron less likely to fire

Basics of allowing messages to be sent throughout the central and peripheral nervous systems:

• Resting potential: -70 millivolts → Polarized

  • Po = positive outside

• Firing threshold: 

  • Fires all or none: once at the threshold, the neuron WILL fire with the same intensity at each fire

• Action potential: An electrical impulse that travels down the axon

  • Depolarization 

    • Change in electricity creates a positive electrical charge (+30 millivolts) inside the neuron

• Refractory period: a brief period where the neuron can’t fire again

• Reuptake: The sending neuron recollects neurotransmitters

Ex, need 3 blue neurotransmitters to fire

• Vesicles open, neurotransmitters lock into postsynaptic dendrite receptors 

• Neuron fires

• Synaptic vesicles release neurotransmitters from the axon terminals

• Neurotransmitters travel across the synapse and fit into the postsynaptic receptor site like a lock and key

Video 4 - Neurotransmitters & Cognition and Behavior

Neurotransmitters

• Chemical messengers of the nervous system, can be excitatory or inhibitory 

• Neurotransmitters vs. hormones

  • Nervous system, floating in synapses and axon terminals

  • Hormones are released by glands in the endocrine system

• Dozens of neurotransmitters in the human nervous system, and each neurotransmitter plays a role in various cognitive and behavioral processes

Glutamate: How exciting it would be to be glued to your mate!

Gaba: Brakes of CNS

Get A Brake Adjustment

Acetylcholine (ACh)

• Found in both the central and peripheral nervous system

• ALL movement involves ACh

• Involved in learning and memory (many other functions too)

  • Alzheimer’s disease is associated with diminished ACh functioning

• To hit an ace in tennis, you need acetylcholine

• To ace your upcoming exam, you need acetylcholine

Dopamine 

• Linked to the anticipation of pleasurable or rewarding activities

• Involved in movement, attention, and learning

  • Lack of dopamine is associated w/ Parkinson’s

  • Excess dopamine is associated w/ Schizophrenia

• Dopamine is linked to pleasure and Parkinson’s

• DopaMINE! Pleasure is mine, mine, mine

Endorphins (endogenous morphine)

• Body’s natural painkiller → involved in pain reduction and reward

• Can be stimulated by intense and prolonged exercise, creating euphoric feelings

• Endorphins and pain

Epinephrine (adrenaline)

• Both a neurotransmitter and a hormone → boosts energy

• The primary chemical in “fight or flight” responses

Norepinephrine (Noradrenaline)

• Arousal, alertness, vigilance (heightened sensitivity to what is going on around you)

• Heavily involved in the sleep cycle

• Low levels associated w/ depression

Serotonin

• Plays a significant role in mood, appetite, sleep, and dreams

• Low levels have been associated with depression

• Serotonin – “rotten,” you avoid rotten food, rotten moods, and rotten nights of sleep
  

Video 5 - How Chemicals Influence Neural Firing

Agonists and Antagonists

• Psychoactive drugs and some other substances have a direct impact on one or more neurotransmitters at the synapse

• Psychoactive drugs work as agonists or antagonists based on how they influence neural transmission

Agonists 

• Enhance the actions of neurotransmitters in various ways

  • Direct agonists mimic the neurotransmitter & bind with the receptor of the next neuron

    • Heroin

      • An agonist for endorphins

      • Mimic - the receptor site can’t distinguish between an endorphin and the chemical structure of heroin

    • Nicotine

      • An agonist for ACh (acetylcholine)

      • Stimulates skeletal muscles and causes increased heart rate

    • Black Widow Venom: Toxin

      • An agonist for ACh (acetylcholine)

      • Causes ACh to be released continuously at neuromuscular junctions (spams, increased. heart rate)

  • Indirect agonists (or reuptake inhibitors) can block the reuptake of a neurotransmitter, a drug/chemical that is introduced at the synapse. Sticks in synapse for longer 

    • Prozac

      • Inhibits reuptake of serotonin. Floods synapse with serotonin

    • Cocaine

      • Inhibits reuptake of dopamine. Floods synapse w/ dopamine

Antagonists

• Inhibit the actions of neurotransmitters in various ways

• Bind to a receptor but do not stimulate.

• Blocks a neurotransmitter from being released by the terminal or from binding to the receptor site

  • Inhibits the normal functioning of the neurotransmitter

    • Botox

      • An antagonist for ACh (acetylcholine)

      • Blacks ACh from reaching receptors

      • Can’t move muscles in the area

    • Thorazine – Early Drug of Schizophrenia

      • An antagonist for dopamine

      • Blocks dopamine receptors, blocking the transmission of dopamine

Video 6 - Tolerance and Withdrawal

Drugs have in common:

• Alter mental states

• Activate dopamine-producing neurons in the brain’s reward system

• Increase in dopamine associated w/ greater reward, → a stronger desire to take drugs again

• Creates tolerance, needing increased amounts of the drug to create the original high/desired effect

• Many drugs lead to physical dependence: repeated use, a person might need to administer drugs to prevent withdrawal symptoms  (Negative reinforcement)

• The effect of a drug depends on which neurotransmitters are affected

Psychoactive Drugs Influence Synaptic Transmission

• All psychoactive drugs have a direct impact on one or more neurotransmitters at the synapse

• Can be classified as agonists or antagonists based on how they influence neural transmission

Blood-Brain Barrier

• A barrier that allows some chemicals to pass from the blood into the brain but prevents other chemicals from entering

• All drugs discussed here are able to pass this barrier to get from blood into brain

Types of Drugs

• Depressants

  • Slow or inhibit CNS functions

  • Create drowsiness, sedation, or sleep – sometimes relieves anxiety and lowers inhibition

  • Combining depressants can be deadly

    • Alcohol

      • 2nd most widely used drug in the US

      • Agonist for GABA (gamma-aminobutyric acid, “brake” for CNS)
        Lessons inhibitions by depressing brain centers responsible for judgment and self-control

• Hallucinogens/Psychedelics

  • Create sensory and perceptual distortions, alter mood, and affect thinking

  • Much current research on psychedelics in therapeutic settings (anxiety, depression, and more) but still in the experimental phase

    • THC

      • Very mild hallucinogen

      • Produces a sense of well-being, mild euphoria, dreamy state of relaxation

      • Ingredient in Marijuana

      • Interferes with muscle coordination, learning, memory, and overall cognitive function

      • Various therapeutic uses

• Opioids

  • Agonist for endorphins

  • Incredible addictive and create powerful withdrawal symptoms

  • Heroin, oxycodone, fentanyl

• Stimulants

  • Activate the sympathetic nervous system

  • Increase brain activity, arouse behavior, and increase mental alertness

    • Caffeine

      • The most widely used drug in the world

      • Promotes wakefulness, mental alertness, and faster thought processes by stimulating the release of dopamine

      • Antagonists for adenosine – blocks sleep-inducing effects

      • Physically addictive and creates withdrawal symptoms

    • Cocaine

      • Dopamine agonist (reuptake inhibitor); also elevates serotonin and norepinephrine

      • Intense euphoria, alertness, and heightened self-confidence

      • Crash after high dissipates and highly addictive