Emergent Properties

• Emergent properties refer to characteristics that arise from the interactions of smaller components within a system.

• In the context of the nervous system, emergent properties illustrate how networks of neurons connect and communicate, leading to complex behaviors and functions.

• These connections enable advanced behaviors, cognitive functions, and physiological responses that cannot be understood by examining individual neurons alone.

Plasticity of the Nervous System

• Definition of Plasticity: The ability of the brain's neural networks to adapt and evolve based on different inputs.

• Importance of Plasticity:

  • Differentiates the capabilities of a neural circuit from an individual neuron.

  • Enables affective behaviors (emotions) and cognitive behaviors (thinking).

Evolution of the Nervous System

Development Across Species

• Jellyfish: Represent primitive nervous systems with a decentralised nerve net, allowing responses to stimuli.

• Flatworm: Develops a simple brain with ganglia along a nerve cord, allowing more coordinated movement.

• Earthworm: Displays a primitive brain structure, aiding in basic sensory movement.

• Fish: Have smaller forebrains indicating less complex processing.

• Goose: Exhibits a larger forebrain, showing a higher capacity for processing.

• Human: The human forebrain is highly developed, dominating in size and function relative to other brain regions. This advancement supports complex thought processes, reasoning, and emotional regulation.

Development of the Human Nervous System

Key Stages

• Weeks 4-11:

  • Week 4: Neural plate cells migrate towards the midline, marking initiation.

  • Week 6: Neural tube differentiates into distinct brain regions, setting foundations.

  • Week 11: Rapid growth of the cerebrum occurs, defining the structure of the brain.

• Birth: The cerebrum covers most brain regions, leading to convoluted surfaces due to growth in a limited space.

Sleep and Its Importance

• Energy Conservation: Sleep reduces metabolic demand, conserving energy for the organism.

• Predator Avoidance: Dormancy during night hours can protect organisms from predators.

• Repair and Recovery: Sleep plays a critical role in bodily recovery, cell repair, and growth hormone release.

• Memory Processing: Sleep aids in memory consolidation, allowing for the integration of experiences into long-term memory.

• Immune Response: Sleep enhances immune function, providing the body with defense mechanisms against illnesses.

• Waste Clearance: The brain clears waste from cerebrospinal fluid (CSF) during sleep, essential for maintaining brain health.

• EEG Utilization: Electroencephalograms (EEG) are employed to measure various stages of sleep and assess brain activity.

Circadian Rhythms

• Definition: Biological patterns of rest and activity, generally following light and dark cycles.

• Regulation: The suprachiasmatic nucleus (SCN) in the hypothalamus acts as the primary circadian clock.

• Implications of Disruption: Disruption of circadian rhythms can negatively impact physical and mental health leading to sleep disorders, mood disturbances, and increased susceptibility to chronic conditions.

Emotions, Motivation, and Moods

Emotions

• Difficult to Define: Common feelings include happiness, fear, anger, and pleasure.

• Role of the Amygdala: Center for emotions in the brain, influencing physiological responses.

Motivation

• Nature of Motivation:

  • Drives behavior towards desires (food) or away from dangers.

  • Often linked to emotions with properties that increase arousal and goal-directed behavior.

• Addiction and Pleasure: Linked to dopamine release in the brain.

Moods

• Definition: Long-lasting emotional states that contribute to one's sense of well-being.

Learning and Memory

Learning Types

• Associative Learning: Linking two stimuli (e.g., Pavlov’s dogs).

• Non-Associative Learning: Subcategories include habituation (decreased response to a repeated stimulus) and sensitisation (increased response after exposure to a strong stimulus).

Types of Memory

• Short Term: Holds 7-12 pieces of information; requires effort for consolidation.

• Long Term: Conversion of short-term to long-term memory through consolidation. Long-term memories can be further classified into explicit (declarative) and implicit (non-declarative) memory.

• Dementia and Trauma: Understanding memory loss in conditions such as dementia and after trauma.

• Language Processing

• Requires sensory input, processing in the cerebral cortex, and motor outputs.

• Key Areas: Wernicke's area (comprehension) and Broca's area (production).

  • Damage to either area affects language capabilities (receptive/expressive aphasia).

Personality Development

• Influenced by both genetic and environmental factors.

• Schizophrenia as an example of complex personality development:

  • Genetic risks categorized by familial and twin studies.

  • Treatments often target neurotransmitter systems, particularly dopamine activities.

Learning Outcomes

Students should be able to:

• Describe emergent properties, including plasticity and behaviors.

• Understand the evolution and development of the nervous system.

• Explain why sleep is necessary and how it is monitored with EEG.

• Discuss circadian rhythms and their physiological impacts.

• Define emotions and motivations.

• Differentiate between various learning and memory types.

• Explain language integration in the brain.

• Understand personality's development and its association with schizophrenia.