Notes on Biological Bases of Behavior

Biological Bases of Behavior

  • Biological Psychology: Explore the links between biology and behavior/mental processes.
  • Key Modules:
    • Biological Psychology and Neurotransmission
    • The Nervous and Endocrine Systems
    • Studying the Brain and Older Structures
    • Cerebral Cortex
    • Brain Hemisphere Organization
    • Behavior Genetics
    • Evolutionary Psychology

Neurons and Neural Impulses

  • Neuron: Basic nerve cell; building block of the nervous system.
  • Parts of Neuron:
    • Dendrites: Receive messages from other cells.
    • Cell Body (Soma): Contains the nucleus; life-support center.
    • Axon: Passes messages to other neurons, muscles, or glands.
    • Myelin Sheath: Fatty layer that speeds up neural impulses.
    • Terminal Branches: Form junctions with other cells; contain neurotransmitter vesicles.
Action Potential Generation
  • Threshold: Required level of stimulation to trigger a neural impulse.
  • All-or-None Response: Neurons fire at full intensity or not at all.
  • Neural Impulse:
    • Resting State: Neuron is polarized with Na$^+$ outside and K$^+$ inside.
    • Depolarization: Na$^+$ flooded in, changing the axon's electrical charge.
  • Movement of Impulse: Propagates down the axon like falling dominoes.
Neuron Communication
  • Synapse: Junction between sending and receiving neurons.
  • Neurotransmitters: Chemicals that transmit signals across synapses.
    • Reuptake: Neurotransmitter reabsorption by sending neuron.

Neurotransmitter Functions

  • Acetylcholine (ACh)
    • Function: Muscle action, learning, memory.
    • Malfunction: Alzheimer’s disease; muscle paralysis when blocked.
  • Dopamine
    • Function: Movement, learning, attention, emotion.
    • Malfunction: Linked to Parkinson’s disease; excess may cause schizophrenia.
  • Serotonin
    • Function: Mood regulation, sleep.
    • Malfunction: Linked to depression.
  • Endorphins
    • Function: Pain control, pleasure.

The Nervous System

  • Central Nervous System (CNS): Brain and spinal cord.
  • Peripheral Nervous System (PNS): Somatic and autonomic systems.
    • Autonomic System: Regulates internal organs,
    • Sympathetic: Arouses body (fight or flight).
    • Parasympathetic: Calms body (rest and digest).

The Endocrine System

  • Hormones: Chemical messengers that travel in blood.
  • Major Glands:
    • Pituitary: Master gland regulating other glands.
    • Adrenal Glands: Release adrenaline during stress responses.

Brain Structure and Function

  • Brainstem: Controls automatic survival functions (heartbeat, breathing).
    • Medulla: Vital functions (breathing, heartbeat).
    • Pons: Coordinates movement, controls sleep.
    • Reticular Formation: Affects arousal, filters stimuli.
  • Cerebellum: Controls balance, motor skills, nonverbal learning.
  • Limbic System: Emotions and memory-related structures.
    • Amygdala: Linked to emotion and aggression.
    • Hippocampus: Processes explicit memories.

Cerebral Cortex

  • Lobes:
    • Frontal Lobe: Decision making, problem-solving, motor activity.
    • Parietal Lobe: Processes sensory information from touch.
    • Temporal Lobe: Handles auditory information.
    • Occipital Lobe: Visual processing.
  • Association Areas: Integrate information for learning, thinking.
Neurogenesis and Brain Plasticity
  • Plasticity: Brain's ability to reorganize and adapt.
  • Neurogenesis: Creation of new neurons, important for recovery/learning.

Behavior Genetics

  • Heredity vs Environment: Nature (genes) vs Nurture (environmental influences).
  • Heritability: Proportion of variation among individuals related to genetics.
  • Twin and Adoption Studies: Show the impacts of nature and nurture on behaviors.

Evolutionary Psychology

  • Natural Selection: Traits that enhance survival and reproduction are passed down.
  • Evolutionary Explanations: Differences in male and female sexuality to ensure reproduction.
  • Criticism and Response: Acknowledgment of social/cultural influences alongside biological.

Conclusion

  • Biopsychosocial Approach: Integrates biological, psychological, and social factors impacting behavior.