Psychology 2E Study Notes

PSYCHOLOGY 2E

INTRODUCTION TO BIOPSYCHOLOGY

  • Biopsychology explores biological mechanisms underlying behavior.

    • Subfields include genetics, nervous system structure and function, and interactions with the endocrine system.

BRAIN IMAGING TECHNIQUES

  • Different brain imaging techniques provide insights into human brain functions:

    • PET scan (Positron Emission Tomography): Shows brain activity using radioactive substances.

    • CT scan (Computed Tomography): Utilizes X-rays to visualize brain structures.

    • fMRI (Functional Magnetic Resonance Imaging): Monitors metabolic activity in the brain over time.

  • Credits for images:

    • Left: Modification of work by Health and Human Services Department, National Institutes of Health

    • Center: Modification of work by “Aceofhearts1968”/Wikimedia Commons

    • Right: Modification of work by Kim J, Matthews NL, Park S.

CELLULAR AND MOLECULAR BIOLOGY

STRUCTURE OF DNA

  • DNA Composition: Basal Structure

    • Contains nucleotide components: Phosphate, Deoxyribose Sugar, Nitrogenous Bases (Adenine, Thymine, Guanine, Cytosine, Uracil).

  • Nucleotide Binding Affinity: Specific base pairs attract complementary nucleotides.

    • Adenine (A) pairs with Thymine (T) through hydrogen bonds.

    • Guanine (G) pairs with Cytosine (C).

  • The ability of nucleotides to bind allows for self-replication of DNA.

GENES

  • Gene Definition: A segment of DNA capable of associating with a protein.

  • Genotype vs. Phenotype:

    • Genotype: All the genes possessed by an individual.

    • Phenotype: The expression of those genes.

NEURONS AND THEIR FUNCTIONS

OVERVIEW

  • Neurons: Basic units of the brain and nervous system.

    • Information flow: From dendrites (receiving information) to axon (sending messages).

    • Each neuron has a single axon but many dendrites.

STRUCTURE OF NEURONS

  • Basic Neuron Structure:

    • Dendrites: Collect information from other neurons.

    • Cell Body/Soma: Contains the nucleus and integrates information.

    • Axon: Conveys messages to other neurons; can have branches (collaterals) and end at terminal buttons (end feet).

INFORMATION PROCESSING IN NEURONS

  • Neurons function in groups (neural networks) to communicate across the brain and spinal cord.

  • Seeking to map the connectome: The physical wiring of the brain.

GENETICS IN PSYCHOLOGY

HUMAN GENETICS

  • Research helps to understand:

    • Variability in disease response.

    • Genetic bases of psychological disorders (e.g., depression).

    • Inheritance patterns of genetic diseases.

THEORY OF EVOLUTION

  • Charles Darwin: Proposed evolution through natural selection; organisms adapt to surroundings and traits favorable to survival are preserved.

    • Quote: "It is not the strongest of the species that survives… it is the one that is most adaptable to change."

EXAMPLE: SICKLE CELL ANEMIA

  • A genetic mutation causing red blood cells to have a crescent shape, affecting function and leading to early mortality.

    • Carriers of this trait show increased malaria resistance.

GENETIC VARIATION

  • Genetic differences begin at fertilization and contribute to species adaptation.

  • Chromosomes: Long strands of DNA; contain genes affecting traits.

    • Genes: Specific sequences coding for traits, may have multiple alleles affecting expression.

DOMINANT AND RECESSIVE ALLELES

  • Polygenic Traits: Traits controlled by multiple genes.

  • Alleles:

    • Dominant allele: Traits expressed regardless of the second allele.

    • Recessive allele: Traits only expressed if homozygous (two identical copies).

  • Heterozygous: Different alleles (e.g., Aa);

  • Homozygous: Same alleles (AA or aa).

PUNNETT SQUARES

  • Used to predict gene interactions in offspring:

    • Example of cleft chin inheritance and phenotype prediction.

    • 25% chance of expressing a specific phenotype for PKU in heterozygous parents.

GENE-ENVIRONMENT INTERACTIONS

  • Nature vs. Nurture: Examines gene and environment interactions influencing individual characteristics.

    • Range of Reaction: Genes set limits; environment influences outcomes.

    • Genetic Environmental Correlation: Genes shape environment, and environment shapes gene expression.

    • Epigenetics: Studies how environments can alter gene expression without changing the DNA sequence.

NEURON STRUCTURE AND FUNCTION

KEY COMPONENTS

  • Dendritic Spines: Increase surface area for synaptic connections.

  • Axon Hillock: Site of action potential initiation.

  • Synapse: Frontier between two neurons for neurotransmitter exchange.

NEURON INFORMATION FLOW

  • Incoming signals received at dendrites → processed in cell body → transmitted down axon to the terminal button.

NEUROTRANSMITTERS

COMMON NEUROTRANSMITTERS

  • Acetylcholine: Muscle action, memory.

  • Dopamine: Mood, learning, sleep.

  • Serotonin: Mood regulation and sleep.

  • Norepinephrine: Alertness and arousal.

  • GABA: Reduces excitability in neurons.

  • Glutamate: Key role in learning and memory.

  • Endorphins: Pain relief and pleasure.

DRUG INTERACTIONS

  • Psychotropic Medications: Affect psychiatric symptoms by restoring neurotransmitter balance.

    • Agonists: Enhance neurotransmitter action.

    • Antagonists: Block neurotransmitter action.

NERVOUS SYSTEM STRUCTURE

DIVISIONS

  1. Central Nervous System (CNS): Brain and spinal cord.

  2. Peripheral Nervous System (PNS): Nerves extending to other body parts.

    • Somatic Nervous System: Controls voluntary movements.

    • Autonomic Nervous System: Controls involuntary actions; further divided into:

      • Sympathetic Nervous System: Prepares body for stress (fight or flight).

      • Parasympathetic Nervous System: Restores body under calm conditions (rest and digest).

BRAIN STRUCTURE

  • Comprises interconnected neurons; organized into distinct but interactive lobes:

    • Forebrain: Higher cognitive processes; includes cerebral cortex, thalamus, hypothalamus, and limbic system.

    • Midbrain: Processes sensory information (e.g., reticular formation).

    • Hindbrain: Manages automated functions (e.g., breathing, heart rate).

CEREBRAL CORTEX AND LOBES

CEREBRAL CORTEX FUNCTIONS

  • Cognitive processes; can be divided into four lobes:

    • Frontal Lobe: Executive functions, motor control, and language production (Broca’s area).

    • Parietal Lobe: Sensory processing.

    • Temporal Lobe: Emotion, memory, and auditory processing (Wernicke’s area).

    • Occipital Lobe: Visual processing.

THALAMUS AND LIMBIC SYSTEM

  • Thalamus: Sensory relay center; directs sense signals (excluding smell).

  • Limbic System: Critical for emotional processing and memory; includes AMYGDALA (emotion), HIPPOCAMPUS (memory), and HYPOTHALAMUS (homeostasis).

BRAIN IMAGING TECHNIQUES

IMAGING TECHNIQUES

  • CT Scan: X-ray imaging of brain structures; useful for identifying tumors.

  • PET Scan: Monitors blood flow and brain activity utilizing radioactivity.

  • MRI: Magnetic imaging revealing brain tissue; fMRI tracks metabolic activity.

  • EEG: Records electrical activities across brain at various frequencies.

SUMMARY

  • The interconnected study of biology, chemistry, and psychology elucidates the biological bases of human behavior, cognition, emotion, and mental health. Understanding the brain's structure, functions, and its neurotransmitter system provides a comprehensive overview of the mechanisms driving psychological phenomena and behavioral outcomes.