Gene-Brain-Behaviour Associations in Neurodevelopment

GENE-BRAIN-BEHAVIOUR ASSOCIATIONS IN NEURODEVELOPMENT

• Presenter: Dr. Beth Johnson (they/them)

• Affiliation: School of Psychological Sciences

• Contact: Beth.Johnson@monash.edu

Importance of Biological Psychology

• Understanding the biological basis of behavior is crucial for psychologists.

• Symptoms or traits may appear similar across different individuals but can have diverse biological origins (aetiologies).

  • Examples of aetiologies: genes, proteins, cells, circuits, environmental factors.

• Influential lifestyle factors include:

  • Sleep

  • Nutrition

  • Stress

  • Exercise

  • Hormonal imbalances

• Recognizing these factors can guide holistic approaches to psychological distress.

Learning Outcomes

1. Understand basic units of the nervous system.

2. Learn about major structures and functions of the central nervous system (CNS).

3. Identify subdivisions of the peripheral nervous system (PNS).

4. Understand the endocrine system's structure and function.

5. Examine the interplay of genetics and environment on psychological functioning.

Part 1: Fundamentals of the Central Nervous System

Nervous System Overview

• Functions as the body's communication network.

• Rapidly transmits and processes signals:

  • Controls movement.

  • Sensation and automatic functions (breathing, heart rate).

  • Enables environmental sensing and decision-making.

Major Structures of the CNS

• Spinal Cord: Transmits signals between brain and body.

• Brain: Processes information and coordinates functions.

• Ganglia & Nerves: Involved in signal transmission within the PNS.

Basic Units of the Nervous System

• Glial Cells:

  • Main immune cells of the brain, protect from infection.

• Neurons:

  • Basic signaling units of the nervous system, transmit information to other neurons.

Neuroanatomy

Neuron Structure

• Components of a Neuron:

  • Dendrites: Receive signals.

  • Axon: Transmits signals.

  • Myelin Sheath: Insulates axon for faster signal transmission.

  • Axon Terminals: Release neurotransmitters to communicate with other neurons.

Spinal Cord Anatomy

• Fibers:

  • Afferent Fibers: Carry sensory information to the brain.

  • Efferent Fibers: Transmit motor commands from the brain.

• Divided into white matter and gray matter.

Brain Structure

Key Brain Regions

• Cerebrum: Largest part, responsible for higher functions (thought, action).

• Cerebellum: Coordinates movement and balance.

Brain Lobes

• Frontal Lobe: Involved in reasoning, planning, movement.

• Temporal Lobe: Processes auditory information.

• Parietal Lobe: Manages sensory information.

• Occipital Lobe: Responsible for vision.

Benefits of a Central Nervous System

• Provides centralized control for:

  • Environmental awareness (e.g., temperature, danger).

  • Internal state regulation (e.g., hunger, thirst).

  • Homeostatic mechanisms to maintain balance in bodily functions.

Homeostasis and Allostasis

Homeostasis

• Process of maintaining stable internal conditions.

• **Control Mechanisms: **

  • Receptors (sensors)

  • Control centers (brain areas)

  • Effectors (muscles/glands)

Allostasis

• Process of achieving stability through change.

• Involves adjustments to cope with stress and environmental demands.

Part 2: Peripheral Nervous System (PNS)

Major Divisions of the PNS

• Central Nervous System (CNS): Consists of the brain and spinal cord.

• Peripheral Nervous System (PNS): Includes cranial and spinal nerves.

  • Autonomic Nervous System (ANS): Controls involuntary functions (heart, glands).

  • Somatic Nervous System: Manages voluntary movements (skeletal muscles).

Autonomic Nervous System Divisions

• Parasympathetic Division: Promotes 'rest and digest' functions.

• Sympathetic Division: Prepares body for 'fight or flight' responses.

Part 3: The Endocrine System

Structures of the Endocrine System

• Includes glands such as:

  • Hypothalamus

  • Pineal Gland

  • Pituitary Gland

  • Thyroid Gland

• Hormonal Interactions: Regulates metabolic processes and behavior.

Hypothalamic-Pituitary-Axis

• Regulates stress and emotional responses.

• Coordinates response to stress through hormonal signals.

Part 4: Genetics and Environment in Psychological Functioning

Understanding Genes

• Genes: Segments of DNA that code for traits and processes.

• Alleles: Variants of a gene influencing specific characteristics.

Neuronal Development

• Key processes include:

  • Neurogenesis

  • Neuron migration

  • Axon outgrowth

  • Circuit formation

• Development continues through adolescence and into adulthood.

Epigenetics

• Study of changes in gene expression influenced by environmental factors.

• Examples of how social stress can affect gene expression and neural development.

The Biopsychosocial Model of Mental Health

• Integrative model considering:

  • Biological factors (genetics, neurochemistry)

  • Psychological factors (emotions, trauma)

  • Social factors (environment, relationships)

• Facilitates a comprehensive understanding of mental health and well-being.