Unit 1 AP psychology

1.1 Interaction of Heredity and Environment

  • Nature vs. Nurture: The interplay between genetics (nature) and environmental influences (nurture).

    • Genetics: Refers to biological inheritance; the genetic code formed before birth.

    • Nurture: Encompasses environmental factors, life experiences, and learning processes over a lifetime.

  • Universal Grammar: Proposed by Noam Chomsky; posits that all humans are born with an innate ability to acquire language.

  • John B. Watson's Perspective: Emphasizes that children are born as 'blank slates' and can be trained to become specialists in any field through environmental influences.

  • Epigenetics: A study of how environmental factors can alter gene expression, showing that nurture can influence nature.

    • Rats Licking Studies: These studies demonstrate how maternal behavior can affect the genetic predisposition of rats leading to high vs low licking, implicating long-term effects on stress response.

  • Identical vs. Fraternal Twins:

    • Identical Twins (Monozygotic): Result from one egg splitting; share 100% of their DNA.

    • Fraternal Twins (Dizygotic): Result from two separate eggs fertilized by different sperm; share approximately 50% of their DNA.

1.2 Overview of the Nervous System

  • Nervous System: Comprises two main parts:

    • Central Nervous System (CNS): Consists of the brain and spinal cord; processes information.

    • Peripheral Nervous System (PNS): Transmits information to and from the CNS; divides into:

    • Somatic Nervous System (SNS): Controls voluntary movements by relaying sensory information to the CNS and motor commands out to the body.

    • Autonomic Nervous System (ANS): Regulates involuntary bodily functions such as heartbeat and blood pressure; further divided into:

      • Sympathetic Nervous System: Activates the ‘fight or flight’ response in stressful situations.

      • Parasympathetic Nervous System: Promotes the ‘rest and digest’ response, helping the body to conserve energy.

1.3 Neuron and Neural Firing

  • Neurons: The fundamental units of the brain and nervous system responsible for transmitting information throughout the body.

  • Glial Cells: Support cells that send signals to and from neurons; constitute about 10 times more than neurons but do not conduct electrical impulses.

  • Neuron Structure:

    • Dendrites: Branch-like structures receiving messages.

    • Soma (Cell Body): Contains the nucleus and processes incoming signals.

    • Axon: Transmits signals away from the soma.

    • Terminal Buttons: Release neurotransmitters into the synapse.

  • Action Potential and Firing:

    • Resting Potential: Typically -70 mV; polarized with a higher concentration of sodium ions outside.

    • Firing Threshold: A level of depolarization where a neuron will fire an action potential with the same intensity (All-or-Nothing Law), typically around -55 mV.

    • Action Potential: Occurs when depolarization reaches +30 mV, causing neurotransmitter release.

    • Refractory Period: A brief period after firing when the neuron cannot fire again.

  • Neurotransmitters: Chemical messengers that cross the synapse to transmit signals from one neuron to another.

    • Types of Neurotransmitters:

    • Glutamate: The most abundant excitatory neurotransmitter; vital for learning and memory by strengthening synaptic connections.

    • Acetylcholine (ACh): Plays a key role in all movements; deficits are associated with Alzheimer's disease.

    • GABA (Gamma-Aminobutyric Acid): The principal inhibitory neurotransmitter, reducing neuronal excitability and preventing excessive activity.

    • Dopamine: Involved in reward processing, attention, and movement; imbalances linked to diseases like Parkinson's and schizophrenia.

    • Endorphins: Natural pain relievers, stimulated by exercise; reduce pain and induce feelings of pleasure.

    • Norepinephrine: Affects arousal, alertness, and sleep cycles; low levels can lead to mood disorders.

    • Serotonin: Regulates mood, appetite, and sleep; low levels noted in depression.

  • Agonists and Antagonists:

    • Agonist Drugs: Stimulate neurotransmitters; examples include Heroin (agonist for endorphins) and Nicotine (agonist for ACh).

    • Antagonist Drugs: Block neurotransmitter action; examples include Botox (antagonist for ACh) and Thorazine (antagonist for dopamine).

1.4 The Brain

  • Brain Structures:

    • Hindbrain: Includes the medulla, pons, and cerebellum.

    • Medulla: Controls vital functions such as heartbeat and breathing.

    • Pons: Aids in sleeping/dreaming and connects various parts of the brain.

    • Cerebellum: Involved in balance, coordination, and motor memory.

    • Midbrain: Relays information between the forebrain and hindbrain.

    • Limbic System: Involved in emotion, motivation, learning, and memory; consists of the thalamus, hypothalamus, amygdala, and hippocampus.

    • Thalamus: Processes sensory information and relays it to appropriate areas in the cortex.

    • Hypothalamus: Controls autonomic functions including hunger, thirst, and emotional responses.

    • Amygdala: Involved in emotional memory formation, particularly fear and aggression.

    • Hippocampus: Critical for memory formation and spatial navigation; damage leads to memory disorders.

    • Cerebral Cortex: Divided into left and right hemispheres, each with four lobes:

    • Frontal Lobe: Higher cognitive functions; controls voluntary movements, decision-making, and planning.

    • Parietal Lobe: Processes sensory information related to touch and spatial orientation.

    • Occipital Lobe: Primary area for visual processing.

    • Temporal Lobe: Involved in auditory processing and language comprehension; contains Broca's and Wernicke's areas.

1.5 Nervous System Research Methods

  • Neuroplasticity: The brain's ability to reorganize itself by forming new connections throughout life; observed in neurogenesis and long-term potentiation (LTP).

    • Neurogenesis: The process of generating new neurons in response to learning and experience.

    • Long-Term Potentiation: Strengthening of synapses based on recent patterns of activity, representing a biological basis for learning.

  • Functional Plasticity: Ability of the brain to move functions from damaged areas to undamaged areas.

  • Methods of studying the brain:

    • Autopsy: Examining brain tissue after death can provide insights into neurological conditions.

    • Case Studies: Intensive studies of a single subject with a specific condition.

    • Surgery: Operative methods to study or treat brain conditions.

    • Brain Scans:

    • EEG (Electroencephalography): Measures electrical activity in the brain, useful for diagnosing conditions like epilepsy.

    • fMRI (Functional Magnetic Resonance Imaging): Measures changes in blood flow and oxygen to assess brain activity.

1.6 Sleep

  • Sleep Cycles: Occur in approximately 90-120-minute durations, containing various stages:

    • NREM (Non-Rapid Eye Movement) Sleep:

    • Stage 1: Light sleep, transition from wakefulness, characterized by alpha waves.

    • Stage 2: Onset of true sleep, marked by sleep spindles and theta waves.

    • Stage 3: Deep sleep, characterized by delta waves.

    • REM (Rapid Eye Movement) Sleep: Associated with vivid dreaming; characterized by increased brain activity and muscle paralysis.

  • Sleep Theories:

    • Restoration Theory: Suggests sleep replenishes energy and supports physical growth and repair.

    • Memory Consolidation Theory: Proposes that sleep is essential for processing and consolidating memories.

    • Energy Conservation Theory: Posits that sleep reduces energy expenditure and supports survival.

  • Common Sleep Disorders:

    • Insomnia: Difficulty falling or staying asleep; can stem from various causes including stress and lifestyle.

    • Sleep Apnea: Characterized by intermittent cessation of breathing during sleep; can lead to daytime drowsiness.

    • Narcolepsy: A condition characterized by excessive daytime sleepiness and sudden sleep attacks.

1.7 Sensation

  • Visual System:

    • Structure of the Eye: Includes components such as the cornea, lens, retina, and iris. The retina contains rods (for light detection) and cones (for color vision).

  • Color Vision Theories:

    • Trichromatic Theory: Proposes the existence of three types of cones responsive to blue, green, and red light.

    • Opponent-Processing Theory: Suggests that color perception is controlled by opposing responses in the brain; when one color is stimulated, the other is inhibited.

  • Auditory System:

    • Structure of the Ear: Comprises the outer ear (pinna), middle ear (tympanic membrane, ossicles), and inner ear (cochlea, organ of Corti).

  • Hearing Theories:

    • Place Theory: Suggests that specific areas of the cochlea correspond to different pitches, explaining high-frequency sounds.

    • Frequency Theory: Proposes that the rate of nerve impulses traveling up the auditory nerve corresponds to the frequency of a tone, explaining lower frequencies.

  • Taste and Smell:

    • Taste Buds: Located on the tongue, capable of detecting sweet, salty, sour, bitter, and umami flavors.

    • Olfaction: Smell signals bypass the thalamus and are directly processed in regions related to emotion and memory, such as the amygdala.

  • Balance and Motion:

    • Vestibular System: Comprising semicircular canals that help maintain balance and perceive spatial orientation.

  • Pain Perception:

    • Gate Control Theory: Suggests that there is a limit to how much pain can be perceived; various factors can influence this perception.