Notes on Biological Bases of Behaviour from Charles Sturt University

Biological Bases of Behaviour

• Influence of the Brain & Nervous System
  • Pain perception and behaviour are heavily influenced by the brain and the nervous system.
  • Central role of neurotransmitters in affecting anxiety, motivation, and pain tolerance in patients.
  • Fear and stress can exacerbate dental pain, highlighting the need for practitioners to understand emotional states.

Neurons: The Building Blocks of the Nervous System

• Types of Neurons:
  • Sensory Neurons: Transmit information from sensory receptors to the brain (afferent).
  • Motor Neurons: Carry commands from the brain to muscles and glands (efferent).
  • Interneurons: Connect various neurons, forming complex neural networks.

Neurotransmitters

• Function: Chemicals facilitating communication between cells.
• Mechanism:
  • Stored in vesicles within the presynaptic cell.
  • Released in response to action potentials.
  • Bind to postsynaptic receptors, leading to graded potentials in the receiving cell.

The Endocrine System

• Composed of glands releasing hormones into the bloodstream.
• Provides global messages throughout the body, influencing behaviour and physiological processes.

The Autonomic Nervous System (ANS)

• Divisions:
  • Sympathetic Division: Activates stress responses (fight-or-flight).
  • Parasympathetic Division: Controls vegetative functions (e.g., digestion).
• Often acts in opposition, but can also cooperate for certain reflexes (e.g., sexual).

Cranial Nerves

• Trigeminal Nerve (Cranial Nerve V):
  • Vital for pain perception, especially in dental contexts (e.g., dental pain and temporomandibular disorders).
  • Motor control for chewing, providing local anesthesia targeting.

Central Nervous System Structure

• Three Main Parts of the Brain:
  • Forebrain: Associated with complex behaviours and higher cognitive functions.
  • Midbrain: Involved in movement and arousal processes.
  • Hindbrain: Regulates essential functions like heart rate and respiration.

The Limbic System & Emotion

• Key Structures:
  • Amygdala: Processes fear and emotional memories.
  • Hippocampus: Critical for memory storage and recall.
• Fear in Dentistry:
  • Patients often fear the dentist due to past traumatic experiences, heightened by amygdala activation.
  • Utilization of relaxation techniques to modulate the fear response is beneficial for patient comfort.

The Cerebral Cortex

• Functions:
  • Controls sophisticated functions such as symbolic thinking, planning, and complex sensory processing.
  • Composed of two hemispheres, each with specialized lobes:
  • Frontal Lobes: Movement coordination, personality, and decision-making.
  • Temporal Lobes: Language and memory.
  • Parietal Lobes: Sensory perception and integration.
  • Occipital Lobes: Vision processing.

Pain Processing in the Brain

• Pain is interpreted in the brain, rooted in contextual factors:
  • Somatosensory Cortex processes pain signals.
  • The emotional response to pain is governed by the amygdala and limbic system.
  • Prefrontal Cortex can modulate pain perception through expectation and distraction.

Importance of the Frontal Lobes

• Phineas Gage Case Study:
  • Demonstrated the critical role of the frontal lobes in personality and behaviour post-injury.

Summary Points

• Understanding biological bases of behaviour is essential for better dental practice:
  • Neuroscience of Pain: Emphasize the role of trigeminal nerves in dental pain transmission and the somatosensory cortex in processing it.
  • Emotional Influence: Recognize how past experiences affect patient anxiety and how the prefrontal cortex can help regulate this fear.
  • Effective Communication: Importance of clinician's expressions, body language, and calming techniques in reducing patient anxiety.
  • ANS Functional Dynamics: Awareness of sympathetic and parasympathetic responses to stress and relaxation fosters improved patient care strategies.