Neurology Foundations 2 Quiz: Brain Development

Course Information

• Course name: Neurology Foundations 2
• Course code: OCCTH 583
• Instructor: Jennifer Krysa, MSc
• Credentials: Registered Occupational Therapist (AB)
• University: University of Alberta

Outline

• Brain Development
• A Spider's Tale
• Neuro Games

Brain Development

• Two phases of neurocircuitry development:
  • In utero: genetically determined events influenced by the maternal environment.
  • Prenatal and postnatal: emerging connections respond to environment and experiences.
• Specific stages of brain development:
  • Neurogenesis
  • Cell Migration
  • Cell Differentiation
  • Cell Maturation
  • Synaptic Formation
  • Synaptic Pruning
  • Myelin Formation

Neurogenesis

• Genesis: the origin or formation of something.
• Neurogenesis: the formation of neurons.
• In utero timeline:
  • Week 3: neurons begin to form, creating the neural tube.
  • Week 6: cells that become the cerebrum begin to divide.
  • 14 weeks: cerebrum is largely formed.
  • 7 months: sulci and gyri (folds) appear.
• Continued neuron formation occurs in the hippocampus throughout middle age.
  • Activities like new learning and exercise can stimulate ongoing neuron generation.

Cell Migration and Differentiation

• Newly formed neurons travel along glial cells to the outer surface of the cerebral cortex.
• The cerebral cortex develops in six layers, sequentially from the inside out.
• Neurons migrate to specific regions of the cortex.
• Neurons differentiate into various cell types, forming axons and dendrites.
• Synapses are created, and neurotransmitters (NTs) are synthesized.

Cell Maturation

• Cells mature at their final location.
• Dendrite formation begins in utero and continues postnatally.
• Dendritic growth is slower than axon growth (approximately 1000 times slower).
• The abundance of axons influences the differentiation of dendrites.
• Initially, more axons and dendrites are produced than are ultimately needed.

Synapse Formation

• Synapse formation starts around week 23 of prenatal development and continues postnatally.
• The prime time for synapse formation is the first two years after birth.
• Up to 700 synapses are formed per second (due to overproduction).
• Basic brain processes develop first, followed by more complex functions.
• Most neural connections develop and locate on the cortex in response to experiences and the environment.

Synaptic Pruning

• Unused neurons and neural circuits are pruned away.
• The most used synapses remain, highlighting the importance of experience and environment in brain development.
• The timing of pruning is variable.
• The visual cortex prunes in early childhood, typically until approximately age six.
• The prefrontal cortex prunes in late adolescence.

Myelin Formation

• Glial cells develop, enabling myelin formation.
• Myelin formation begins prenatally and largely finishes in young adulthood.
• Myelin formation occurs in waves.
• Specific areas of the brain myelinate after age 18:
  • Prefrontal cortex
  • Posterior parietal cortex
  • Anterior temporal cortex

Prefrontal Cortex

• Associated functions:
  • Decision-making
  • Reasoning
  • Social appropriateness
  • Personality expression
  • Complex cognitive behaviors

Posterior Parietal Cortex

• Associated functions:
  • Spatial reasoning
  • Attention
  • Planned movement

Anterior Temporal Cortex

• Associated functions:
  • Semantic memory
  • Knowledge of facts, words, people, and objects

Pattern of Brain Development

• Brain development occurs hierarchically, starting from low-level interpretation of sensory stimuli (prenatal and at birth).
• Higher-level development, such as interpretation of facial expression and language acquisition, emerges.
• Development is heavily influenced by exposure to different environments and experiences during critical periods.
• Skills naturally develop according to this pattern.

Sensitive Periods

• Sensitive periods occur at different ages for different parts of the brain.
• Stimulating environments and experiences enhance brain architecture.
• Early stimulating experiences are crucial for building the foundation for later learning
• Lower-level circuitry must provide precise, high-quality information to the higher-level circuitry for successful complex task performance.
• Neural circuits are formed and pruned.
• Development includes vision, hearing, motor control, emotional response, social cues, and language acquisition.
• As higher-level circuitry matures needs more diverse and sophisticated experiences.
• Early deprivation can have lifelong implications.
• Primary relationships have an impact on brain architecture and development.
• Serve-and-return interactions with caregivers are vital.

Neuroplasticity

• The brain's capacity to form and reorganize synaptic connections in response to positive stimuli (e.g., learning) or negative stimuli (e.g., injury).
• Examples of stimuli promoting neuroplasticity include novelty, complexity, effortful tasks, sustained attention.

A Spider's Tale

• A fictional spider, named Willis, lives on the pons.
• Description of Willis:
  • Nose, eyebrows, suckers for a mouth.
  • Eyes looking outward.
  • Crew cut, fuzzy beard.
  • Two pairs of antennae.
  • Eight legs, two pairs under the head, two pairs attached at the end of the body.
  • Short feelers located at the end of the last pair of legs.
  • Male.

Significance of the Circle of Willis

• Collateral blood flow between anterior and posterior circulations of the brain.
• Protection against ischemia or damage in one or more areas.

Neuro Games

• Launch point for activities and practice related to brain functions in the context of the course topic.