BIOS5130 Week 13 Lecture Part 1 Slides (1)

Emergent Properties

Definition

Emergent properties are characteristics of a complex system that arise from the interactions and relationships among its components, yielding features that the individual parts do not inherently possess. This concept is crucial in understanding systems spanning biological organisms, social networks, and even computational systems.

Plasticity in the Nervous System

Neuronal Circuits

Neurons interconnect to form circuits, leading the entire nervous system to exhibit capabilities and properties that transcend those of any singular neuron. These circuits facilitate communication and processing functions within the brain, allowing for complex behaviors and responses to stimuli.

Plasticity

Plasticity refers to the dynamic capability of brain networks to adapt and reorganize in response to experiences, learning, and environmental inputs. Unlike traditional computers that follow fixed programming, the brain is continually reshaping its neural pathways, enhancing or weakening connections based on activity and interactions.

Types of Behaviours

• Affective: Relating to feelings and emotions, often influencing social interactions and psychological states.

• Cognitive: Pertaining to mental processes such as thinking, memory, problem-solving, and language, essential for learning and decision-making.

Evolution of the Nervous System

Simpler Organisms

• Jellyfish: Possessing a basic nerve net that enables simple reflex actions but lacks a central brain structure.

• Flatworms: Feature a more organized nervous system with a primitive brain capable of processing more complex behaviors than jellyfish.

• Earthworms: Exhibit an enhanced organization with a defined primitive brain and nerve cords that coordinate movements and responses.

Complexity Increase

As evolutionary processes advance:

• Fish develop a rudimentary forebrain, initiating more complex sensory processing and behavioral responses.

• The goose has a relatively larger forebrain compared to its overall brain structure, supporting more advanced cognitive functions than simpler vertebrates.

• Humans exhibit a highly developed forebrain, which dwarfs other brain parts, facilitating advanced reasoning, planning, and abstract thought.

Development of the Human Nervous System

Key Stages

• Day 20: Migration of neural plate cells toward the midline, marking the beginning stages of the nervous system's formation.

• Day 23: Completion of neural tube formation with the anterior portion differentiating into the Central Nervous System (CNS) and the posterior into the Peripheral Nervous System (PNS).

• Weeks 4-11 Development:

  • 4 Weeks: Initial formation of the neural tube, a pivotal stage for spinal cord and brain development.

  • 6 Weeks: Differentiation occurs, leading to distinct brain regions and their functions.

  • 11 Weeks: Development of the cerebrum and other critical brain structures, laying the groundwork for higher cognitive functions.

• 40 Weeks: At birth, the cerebrum is significantly developed, encompassing and reshaping other brain areas due to spatial constraints in the cranium, allowing for basic functions and emotional responses.

Importance of Sleep

Role of Sleep

Sleep serves as a crucial restorative period for the body and mind, facilitating memory consolidation, enhancing immune system function, and clearing waste products from the brain. Sleep is also linked to energy conservation and potentially plays a role in predator avoidance in evolutionary terms.

Measurement

EEG (Electroencephalogram) techniques are employed to monitor different sleep stages, providing insights into its multifaceted roles in maintaining health and well-being.

Circadian Rhythms

Definition

Circadian rhythms are natural, internal processes that maintain a roughly 24-hour cycle, responding primarily to environmental light and darkness cues.

Suprachiasmatic Nucleus (SCN)

The SCN, located in the hypothalamus, acts as the main regulatory center for circadian rhythms, synchronizing physiological processes with environmental cues.

Influence of Melatonin

Melatonin is a hormone that plays a key role in regulating sleep/wake cycles. Disruptions to melatonin production can adversely affect both mental and physical health, linking circadian misalignments to various disorders.

Emergent Properties of Neural Networks

Emotion and Motivation

Emotion arises from complex neural pathways that influence physiological responses, such as changes in heart rate and stress levels. Motivation, driven by internal stimuli, influences voluntary actions and is categorized into various drives that lead to increased alertness and goal-oriented behaviors.

Understanding Emotions

Defining emotions can be challenging, yet they encompass primary states such as happiness, fear, and anger. The amygdala serves as the central hub for emotional processing within the limbic system, playing a role in how we experience and respond emotionally.

Motivation Factors

Directionality

Motivation can direct behavior towards achieving rewards (e.g., obtaining food) or away from threats, influencing decision-making in complex situations.

Arousal Properties

Motivational states elevate CNS activity, prompting behavior that seeks satisfaction—a critical factor in understanding behavioral patterns and psychological states.

Mood as an Emotional State

Mood encompasses a more prolonged emotional state than immediate emotions, often indicating overall well-being and mental health.

Learning and Memory

Types of Learning

• Associative Learning: The ability to link stimuli, exemplified by Pavlov's conditioning experiments with dogs.

• Non-associative Learning: Refers to behavioral changes resulting from repeated exposure to a stimulus, including habituation and sensitization.

Memory Types

Memory involves the processes of storing and recalling information, characterized by forms such as short-term memory, long-term memory, reflexive memory, and declarative memory.

• Short-term Memory: Holds a limited amount of information (typically 7-12 bits) unless strategies are employed to facilitate conversion into long-term memory.

• Long-term Memory: Involves the consolidation of short-term memories into more stable, retrievable forms for later recall.

Language Processing

Language processing incorporates sensory input and motor output, predominantly coordinated in the cerebral hemispheres' language centers, particularly Wernicke’s and Broca’s areas.

Damage Effects

• Wernicke's Area: Damage may result in receptive aphasia, characterized by an inability to comprehend language despite fluent speech.

• Broca's Area: Damage results in expressive aphasia, leading to difficulty in speech production and word formation.

Personality Formation

Personality is generally viewed as the product of both genetic predisposition and individual experiences throughout life.

Schizophrenia

This mental disorder is influenced by a combination of genetic and environmental factors, with treatments often focusing on regulating neurotransmitter activity, notably dopamine, to manage symptoms.

Learning Outcomes

Students should gain a comprehensive understanding of emergent properties in biological and psychological systems, the evolution and