Week 2 - Biological bases of mental life and behaviour.

Biological Basis of Mental Life and Behavior

  • Overview of key components influencing behavior: neurons, neurotransmitters, endocrine system, peripheral and central nervous systems.

Neurons

  • Neurons are the basic units of the nervous system, responsible for receiving, conducting, and transmitting signals.

  • Structure: soma (cell body), dendrites (receive signals), axon (transmits signals), terminal buttons (release neurotransmitters).

  • Synapse: Junction where neurons communicate; allows neurotransmitter release.

Signal Transmission

  • Neurons generate electrical impulses (action potentials) when stimulated.

  • Action potentials propagate signals over long distances along the axon.

  • Graded potentials occur when stimuli are insufficient to trigger an action potential but may contribute to one if strong enough.

Neurotransmitters

  • Chemicals that mediate communication between neurons.

  • Excitatory neurotransmitters (e.g., dopamine) increase likelihood of action potentials; inhibitory neurotransmitters (e.g., GABA) decrease it.

  • Role of dopamine in reward pathways and addiction; implications for disorders like Parkinson's and schizophrenia.

  • GABA: Major inhibitory neurotransmitter; associated with anxiety and its regulation.

Endocrine System

  • A collection of glands that regulate bodily functions through hormone secretion.

  • Hormones impact a broader range of functions than neurotransmitters, activating various body cells through blood circulation.

Nervous System

  • Divided into central nervous system (CNS: brain and spinal cord) and peripheral nervous system (PNS: neurons outside CNS).

  • PNS further divides into somatic (voluntary movements) and autonomic (involuntary functions).

Autonomic Nervous System

  • Sympathetic Nervous System: Activates fight or flight response under stress.

  • Parasympathetic Nervous System: Rest and digest functions, maintaining homeostasis.

Central Nervous System (CNS)

  • Consists of the brain and spinal cord, processing and relaying information.

  • Reflexes are automatic responses, occurring through reflex arcs comprising sensory neurons, interneurons, and motor neurons.

Brain Structure

  • Divided into three main parts: hindbrain, midbrain, and forebrain.

    • Hindbrain: Responsible for basic life functions (e.g., heart rate, coordination).

    • Midbrain: Relays sensory information and aids in alertness and attention.

    • Forebrain: Involved in complex functions like emotion, memory, and reasoning (includes limbic system and cerebral cortex).

Brain Functions

  • Four lobes: occipital (vision), temporal (hearing/language), parietal (touch/spatial awareness), frontal (planning/memory).

  • Each hemisphere controls opposite body sides; significant damage can lead to paralysis on the opposite side of the body.