Psychology Chapter on Sleep and Disorders

Introduction to Psychology

• Psychology is the study of the mind and behavior
• It focuses on observable behaviors, rather than internal states like intentions or expectations

Neurons and the Nervous System

• Neurons are cells in the nervous system that transmit information through electrochemical impulses.
• Three main parts of a neuron:
  • Cell Body: Controls the cell's activities
  • Dendrites: Branch-like structures that receive input from other neurons.
  • Axon: A long, thin fiber that transmits information to other neurons, muscles, or glands.
• Glia (glial cells) support neurons by insulating them, synchronizing activity, and removing waste products.
• Action Potential: An electrical impulse that travels along the axon at a constant strength.
• All-or-None Law: The action potential either occurs fully or not at all; it does not vary in strength or speed.
• Process of Action Potential: -Sodium gates open, allowing sodium ions (Na+) to enter the axon, creating a positive charge. -After the action potential passes, sodium gates close, and potassium gates open, allowing potassium ions (K+) to exit the axon, restoring the negative charge. -The process repeats along the axon, propagating the signal.
• Synapses and Neurotransmitters: The junction between two neurons where communication occurs.
• Terminal Bouton (Presynaptic Ending): releases neurotransmitters, which are chemicals that activate receptors on the postsynaptic neuron.
• Examples of neurotransmitters: Quick (Hearing, vision), Slower (Taste, smell), Very Slow (Hunger, thirst, sex drive); Dopamine, Serotonin, Acetylcholine, GABA, Glutamate, etc.

Drugs and Their Effects

• Drugs alter behavior by influencing synaptic communication.
• They may increase or decrease neurotransmitter release or alter receptor sensitivity.
• Classes of drugs:
  • Stimulants (e.g., cocaine, amphetamines) increase alertness and energy.
  • Hallucinogens (e.g., LSD, psilocybin) alter perception and mood.
  • Anxiolytics (e.g., benzodiazepines) reduce anxiety.
  • Opiates (e.g., heroin, morphine) relieve pain and induce euphoria
• Mechanisms of commonly abused drugs:
  • Cocaine blocks dopamine reuptake, increasing dopamine levels.
  • Alcohol enhances GABA activity, reducing neural activity.
  • Nicotine mimics acetylcholine, stimulating reward pathways.

Brain and Behavior

• Monism: The view that mental activity is inseparable from physical brain activity, consciousness is a product of brain processes.

• Brain Structure and Function:

  • Cerebral Cortex: Outer layer of the forebrain, divided into four lobes:
    • Occipital lobe responsible for vision
    • Temporal lobe responsible for hearing, memory, and emotion
    • Parietal lobe responsible for spatial attention and sensory integration
    • Frontal lobe responsible for motor control, decision-making, and impulse control
  • Hemispheres: Left and right, connected by the Corpus Callosum
  • Measuring brain activity:
    • EEG: Measures electrical activity on the scalp
    • MEG: Records magnetic changes in the brain
    • PET: Tracks radioactivity from injected chemicals -fMRI: Measures oxygen levels in blood to detect brain activity

• Subcortical areas: Hypothalamus, Pons, Medulla, Cerebellum

• Autonomic Nervous System: Controls involuntary bodily functions (sympathetic, parasympathetic)

• Brain Plasticity: The brain's ability to reorganize itself by forming new neural connections, allowing for recovery from brain injury and adaptation to new experiences

Social Neuroscience

• Studies the biological bases of social behavior
• Oxytocin: Hormone involved in social bonding

The Binding Problem

• The question of how separate brain areas combine to produce a unified perception of a single object

Genetics and Evolutionary Psychology

• Chromosomes are strands of hereditary material.
• Genes control chemical reactions that direct development.
• Dominant vs Recessive Genes:
  • Dominant genes are expressed even with one copy
  • Recessive genes are expressed only if the dominant gene is absent
• Sex-linked and Sex-limited genes
• Epigenetics: Study of how environmental factors influence gene expression without altering the DNA sequence.
• Heritability: The proportion of variation in a trait due to genetics. (measured by comparing monozygotic and dizygotic twins)
• Genes influence behavior directly and indirectly.
• Multiplier effects can amplify genetic advantages.

Sensation and Perception

• Sensation: Conversion of environmental energy into neural signals.

• Perception: Interpretation of sensory information.

• Vision:

  • Light strikes the retina, triggering rods (night vision) and cones (color and detail)
  • Blind Spot: Where the optic nerve exits the eye -Trichromatic Theory: three types of cones (red, green, blue) detect different wavelengths
  • Opponent-Process Theory: Color perception involves opposing pairs (red-green, blue-yellow) -Retinex Theory:The brain compares light patterns from different parts of the retina to create color constancy (e.g. recognizing colours regardless of different lighting contexts)

• Dark Adaptation: The process of adjusting to low light levels, primarily involving rods.

• Hearing: Sound waves vibrate the eardrum, causing tiny bones in the cochlea to stimulate hair cells (frequency principle, place principle)

  • Pitch Perception:

• Touch: Warmth, pain, itch, vibration, and tickle

• Gate Theory of Pain: Pain signals can be blocked in the spinal cord

• Taste and Smell: Detects chemicals on the tongue and airborne molecules respectively.

• Sensory Thresholds: (Absolute Threshold, Signal Detection Theory)

• Subliminal Perception

• Feature Detectors

• Gestalt Psychology: Emphasizes perception of overall patterns (e.g., proximity, similarity, continuation, closure, good figure)

• Depth Perception: Binocular cues (retinal disparity and convergence), Monocular cues

Learning

• Behaviorism: Focuses on observable behaviors, not internal states
• Classical Conditioning (Pavlovian Conditioning): Learning a new association between two stimuli.
  • Unconditioned Stimulus (UCS)
  • Unconditioned Response (UCR)
  • Conditioned Stimulus (CS)
  • Conditioned Response (CR)
• Extinction: When the CR weakens due to repeated CS in the absence of the UCS
• Spontaneous Recovery: The temporary return of an extinguished response
• Stimulus Generalization & Discrimination: Responding to similar stimuli (generalization) or differently to stimuli that predict different outcomes (discrimination)
• Drug Tolerance
• Operant Conditioning (Instrumental Conditioning): Changing behavior by providing a reinforcer after a response.
• Reinforcement: Increases the likelihood of a behavior
• Primary Reinforcers: Naturally reinforcing
• Secondary Reinforcers: Learned through association.
• Punishment: Decreases the likelihood of a behavior
• Shaping: Reinforcing successive approximations to change behavior
• Chaining: reinforcing a sequence of behaviors to form a complex one
• Schedules of Reinforcement:
  • Fixed-Ratio
  • Variable-Ratio
  • Fixed-Interval
  • Variable-Interval

Preparedness

• Animals (including humans) learn to avoid foods that make them ill (conditioning)
• Birds learn songs during a sensitive period
• Learning by observing others (social learning, vicarious reinforcement/punishment, self-efficacy)

Personality

• Various theories of personality:

  • Humanistic (Rogers): Importance of conscious perceptions, emotions, and present state; the self-concept

  • Cognitive (Kelly): How individuals cognitively construct their reality; constructs that interpret and predict events.

  • Trait (Cattell): Personality comprises stable patterns of behavior, source traits

  • Behavioral (Skinner): Behavior is shaped by consequences

  • Social Learning (Bandura): Observational learning and self-efficacy; learning from others

  • Psychosocial (Erikson): 8 stages of psychosocial development; challenges and crisis.

  • Maslow's Hierarchy of Needs:

    • Physiological Needs
    • Safety Needs
    • Love and Belonging Needs
    • Esteem Needs
    • Self-Actualization Needs
    • Cognative
    • Aesthetic