Psychology 101 - Brain & Nervous System

Overview

• The brain and nervous system are critical components in understanding human behavior and mental processes.

The Nervous System

• Central Nervous System (CNS): Comprises the brain and spinal cord. It processes information and coordinates activities.

• Peripheral Nervous System (PNS): Connects the CNS to the rest of the body. It includes:

  • Somatic Nervous System: Controls voluntary movements and transmits sensory information.

  • Autonomic Nervous System: Regulates involuntary bodily functions. It has two divisions:

    • Sympathetic Nervous System: Prepares the body for stress-related activities (fight or flight response).

    • Parasympathetic Nervous System: Conserves energy and restores the body to a calm state (rest and digest).

The Brain

• The brain is divided into several key regions, each with specific functions:

  • Cerebrum: Responsible for higher brain functions such as thought, action, and emotion. Divided into two hemispheres:

    • Left Hemisphere: Associated with logical reasoning, analytical thinking, and language skills.

    • Right Hemisphere: Associated with creativity, intuition, and spatial abilities.

  • Cerebellum: Coordinates muscle movements and balance.

  • Brainstem: Controls basic life functions such as heartbeat and breathing. It includes:

    • Midbrain

    • Pons

    • Medulla Oblongata

• Limbic System: Involved in emotion and memory. Major structures include:

  • Amygdala: Processes emotions like fear and pleasure.

  • Hippocampus: Essential for memory formation and spatial navigation.

Neurons and Neurotransmitters

• Neurons: The basic building blocks of the nervous system that transmit information throughout the body.

  • Types of Neurons:

    • Sensory Neurons: Relay sensory information to the CNS.

    • Motor Neurons: Transmit signals from the CNS to muscles or glands.

    • Interneurons: Connect neurons within the CNS.

• Neurotransmitters: Chemical messengers that transmit signals across synapses between neurons. Examples include:

  • Dopamine: Involved in movement, emotion, and reward.

  • Serotonin: Regulates mood, appetite, and sleep.

  • Acetylcholine: Plays a role in learning and memory, as well as muscle movement.

Conclusion

• Understanding the brain and nervous system is essential for exploring various psychological phenomena, from basic functions to complex behaviors.

Research Designs in Psychology

1. Experimental Design

   • Description: Involves manipulation of variables to establish cause-and-effect relationships.

   • When to Use: Best for testing hypotheses and determining causal links.

   • Strengths: Control over variables; can infer causation.

   • Weaknesses: May lack ecological validity; ethical concerns with certain manipulations.

2. Correlational Design

   • Description: Examines the relationship between two or more variables without manipulation.

   • When to Use: Useful for exploring associations, where manipulation is impractical or unethical.

   • Strengths: Can analyze variables in natural settings; easier to conduct.

   • Weaknesses: Cannot establish causation; potential for third variable effects.

3. Longitudinal Design

   • Description: Studies the same subjects over a long period.

   • When to Use: Appropriate for developmental and life-span research.

   • Strengths: Allows observation of changes over time; effective for studying temporal relationships.

   • Weaknesses: Time-consuming; potential for participant attrition.

4. Cross-Sectional Design

   • Description: Compares different groups at one point in time.

   • When to Use: Ideal for examining differences across demographics.

   • Strengths: Quick data collection; less expensive than longitudinal studies.

   • Weaknesses: Cannot track changes over time; cohort effects may bias results.

5. Case Study Design

   • Description: In-depth study of an individual or small group.

   • When to Use: Useful for rare phenomena or complex issues that need comprehensive exploration.

   • Strengths: Rich detail; can provide insights that larger studies might miss.

   • Weaknesses: Limited generalizability; potential researcher bias.

Sampling and Bias

• Sampling: The process of selecting individuals from a population to study. The goal is to ensure that the sample is representative of the population.

• Bias: Systematic errors that can affect the validity of research; includes selection bias, confirmation bias, and response bias, among others.

Ethical Principles in Psychology

1. Beneficence: Obligation to minimize harm and maximize benefits.

2. Non-maleficence: Commitment to avoiding harm to participants.

3. Autonomy: Respecting the rights and dignity of individuals, including informed consent.

4. Justice: Fair distribution of benefits and burdens among participants.

5. Integrity: Commitment to honesty and transparency in professional interactions and conducting research.

• Importance: These principles ensure the protection of participants and the integrity of the research process.

Structure and Function of a Neuron

• Structure: Neurons consist of a cell body, dendrites, axon, myelin sheath, and axon terminals.

• Function: Neurons transmit electrical impulses (action potentials) and communicate through neurotransmitters at synapses.

Basic Brain Structures and Their Functions

1. Cerebrum: Responsible for higher brain functions such as thought, action, and decision-making.

2. Cerebellum: Coordinates movement and balance; important for motor control.

3. Brainstem: Controls basic life functions like heartbeat and breathing.

4. Limbic System: Associated with emotions, memory, and motivation.

Divisions of the Peripheral Nervous System (PNS)

1. Somatic Nervous System: Controls voluntary muscle movements and conveys sensory information.

2. Autonomic Nervous System: Regulates involuntary bodily functions.

   • Divided into:a. Sympathetic Nervous System: Prepares the body for stressful situations.b. Parasympathetic Nervous System: Calms the body and conserves energy after stress.

Key Terms in Neuroscience

1. Neuroscience: The scientific study of the nervous system, including the brain and its impact on behavior and cognitive functions.

2. Neurons: The basic building blocks of the nervous system that transmit information throughout the body.

   • Dendrites: Extensions of a neuron that receive signals from other neurons.

   • Cell Body: Contains the nucleus and organelles of the neuron; processes the information received.

   • Axon: A long, thin projection that transmits impulses away from the cell body to other neurons or muscles.

   • Myelin Sheath: A fatty layer that insulates the axon, speeding up the transmission of impulses.

   • Neurotransmitter: Chemical messengers that transmit signals across synapses between neurons.

   • Synaptic Gap: The space between the axon terminal of one neuron and the dendrite of another where neurotransmitters work.

3. Glial Cells: Support cells in the nervous system that provide support, nourishment, and protection for neurons.

4. PET Scan: A brain imaging technique that helps to visualize metabolic activity by detecting radioactive tracers introduced into the body.

5. fMRI: Functional Magnetic Resonance Imaging; measures brain activity by detecting changes in blood flow.

6. Agonist: A substance that activates a receptor to produce a biological response.

7. Antagonist: A substance that blocks or dampens a biological response by binding to and blocking a receptor.

8. Acetylcholine: A neurotransmitter involved in learning, memory, and muscle movement.

9. Dopamine: A neurotransmitter that plays a key role in movement, mood regulation, and reward processing.

   • Parkinson’s Disease: A neurodegenerative disorder characterized by a deficit in dopamine production, affecting movement and coordination.

10. Blood-Brain Barrier: A selective permeability barrier that protects the brain from harmful substances in the blood while allowing essential nutrients to pass through.

11. L-Dopa: A medication used to treat Parkinson’s disease, aiding in the synthesis of dopamine.

12. Serotonin: A neurotransmitter that regulates mood, appetite, and sleep.

13. Norepinephrine: A neurotransmitter involved in regulating arousal and alertness.

14. SSRIs (Selective Serotonin Reuptake Inhibitors): A class of drugs used to treat depression by increasing serotonin levels.

15. SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors): A class of drugs that treat depression by increasing levels of serotonin and norepinephrine.

16. GABA: A neurotransmitter that inhibits nerve transmission in the brain, relaxing the nervous system.

17. Glutamate: The most abundant excitatory neurotransmitter in the brain, involved in memory and learning.

18. Endorphins: Neurotransmitters that act as natural pain relievers and are involved in pleasure and reward.

19. Central Nervous System (CNS): Comprises the brain and spinal cord and processes information from the body.

20. Peripheral Nervous System (PNS): Connects the CNS to the rest of the body and includes:

    • Somatic (Skeletal) Nervous System: Controls voluntary movements and conveys sensory information.

    • Autonomic Nervous System: Manages involuntary bodily functions, divided into:

      • Sympathetic Nervous System: Prepares the body for stressful situations (fight or flight response).

      • Parasympathetic Nervous System: Calms the body and conserves energy after stress.

21. Endocrine Glandular System: A system of glands that secretes hormones directly into the bloodstream; key glands include:

    • Pituitary Gland: Often termed the 'master gland', regulates other endocrine glands and controls various hormonal functions.

22. Emotion: A complex psychological state that involves a subjective experience, a physiological response, and a behavioral or expressive response.

23. James-Lange Theory: A theory suggesting that emotions arise from physiological reactions to events.

24. Cannon-Bard Theory: A theory positing that emotion and physiological reactions occur simultaneously and independently.

25. Schachter-Singer Two-Factor Theory: A theory stating that emotion is based on physiological arousal and cognitive labeling of that arousal.

Key Brain Structures and Their Functions

26. Medulla: Regulates vital functions such as heartbeat and breathing.

27. Pons: Connects different parts of the brain and assists in regulating sleep and arousal.

28. Reticular Formation: A network of neurons involved in regulating arousal and consciousness.

29. Cerebellum: Coordinates muscle movements and balance; important for motor control.

30. Basal Ganglia: Involved in movement control and coordination.

31. Limbic System: Associated with emotions, memory, and motivation, consisting of:

    • Hypothalamus: Regulates body temperature, hunger, and thirst; involved in emotional responses.

    • Hippocampus: Essential for memory formation and spatial navigation.

    • Amygdala: Processes emotions like fear and pleasure.

32. Cerebral Cortex: The outer layer of the brain responsible for higher cognitive functions, divided into:

    • Frontal Lobe: Involved in reasoning, planning, speech, movement, and emotions.

    • Parietal Lobe: Processes sensory information such as touch, temperature, and pain.

    • Temporal Lobe: Involved in auditory processing and memory.

    • Occipital Lobe: Responsible for visual processing.

33. Motor Cortex: Controls voluntary muscle movements.

34. Somatosensory Cortex: Processes sensory input from the body.

35. Association Cortex: Integrates sensory and motor information, involved in complex functions like thought and perception.

36. Broca's Area: Involved in language expression and speech production.

37. Wernicke's Area: Responsible for language comprehension.

38. Consciousness: Awareness of oneself and the environment; includes alertness, perception, and attention.

39. REM (Rapid Eye Movement): A sleep stage characterized by rapid movement of the eyes, increased brain activity, and vivid dreaming.

Understanding these terms is crucial for exploring the structures and functions of the nervous system and their relationship to behavior and emotional responses.