Biological Psychology Notes

Stay Positive & Professional

• Emphasized throughout the lecture materials.

The Human Brain and Nervous System

• Course Overview: SHDH2187 Biological Psychology
• Quotes: "Keep your face always toward the sunshine - and shadows will fall behind you." --Walt Whitman

Previous Lecture Highlights

• Key Topics:
  • Basic course information
  • Phenomena related to human consciousness:
    • Blindsight
    • Split-brain
    • Unilateral Neglect
    • The Rubber Hand Illusion
  • Brain facts:
    • Larger size may not mean better function; efficiency declines past a certain size.
  • Three Key Points:
    • Perception occurs in the brain.
    • Brain activity is tied to mental activity.
    • Clarification needed on behavior explanations.

Today's Lecture Overview

• Focus Areas:
  • Neurons:
    • Structure
    • Action potential
    • Neuronal communication
  • Brain Structures:
    • Vocabulary of brain areas
    • Functions associated with them

The Nervous System (NS)

• Components:
  • Composed of: Brain, spinal cord, nerves.
  • Primary function: Transmits messages between the brain and body.

Nervous System Division

• Central Nervous System (CNS):
  • Brain and spinal cord.
• Peripheral Nervous System (PNS):
  • Everything outside the CNS, with subcategories:
    • Autonomic Nervous System
      • Sympathetic Nervous System: controls fight-or-flight reactions.
      • Parasympathetic Nervous System: controls rest-and-digest functions.
    • Somatic Nervous System: manages voluntary actions.

Neurons Overview

• Quantity: Adult human brain has ~86 billion neurons (approx. 100 billion in total).
• Function: Neurons process and transmit information.
• Types of Neurons:
  • Sensory Neurons:
    • Detect changes in the environment, sending info to CNS.
    • Afferent axons bring information inward.
  • Motor Neurons:
    • Control muscle contractions or gland secretion.
    • Efferent axons carry information outward.
  • Interneurons:
    • Located within a structure, relaying messages (e.g., thalamus).

Neuron Structure

• Basic Parts:
  • Soma (Cell Body): Contains the nucleus.
  • Dendrites: Receive signals from other neurons.
  • Axon: Transmits signals away from the soma to terminal buttons.
  • Myelin Sheath: Insulates axons, speeding up transmission.
  • Terminal Button: Forms gaps (synapse) with other neurons and releases neurotransmitters.

Synapse and Neurotransmitter Functionality

• Synapse: Junction between axon terminal of one neuron and membrane of another.
• Neurotransmitters: Chemicals released from terminal buttons that influence action potentials in receiving neurons.
  • Types:
    • Excitatory (e.g., glutamate).
    • Inhibitory (e.g., GABA).

Blood-Brain Barrier

• Function: Protects the brain by blocking harmful substances while allowing needed nutrients through.
• Challenges: Makes treating brain conditions (like cancer) difficult.

Action Potential - The Electrical Signal

• Definition: An all-or-none electrical signal that travels down an axon after reaching a threshold.
  • Triggered by the influx of Na+ ions causing depolarization.

Membrane Potential Concepts

• Resting Membrane Potential: Neuron's status when not transmitting a signal (-70mV).
• Action Potential Initiation: Involves sodium and potassium ions moving across the membrane.
  • Stages:
    1. Depolarization (Na+ influx).
    2. Repolarization (K+ efflux).
    3. Hyperpolarization.

Synaptic Transmission

• Process:
  1. Action potential causes neurotransmitter release.
  2. Neurotransmitters bind to postsynaptic receptors, leading to EPSP or IPSP.

Conclusion

• Required Readings:
  • Kalat Chapter 1 & 2
  • Carlson Chapter 2