Neural Development and Piaget's Cognitive Stages - Week 2 Part 1

Dendrites

Receive neural signals from other neurons.

Cell Body

Contains the nucleus and other typical organelles of a neuron.

Axon

Propagates an electrical neural signal to an adjoining neuron.

Gray Matter

Brain region that includes cell bodies and dendrites.

White Matter

Made of myelinated axon bundles forming connections between brain regions.

Prenatal Neurogenesis & Extrinsic Factors

Most neurogenesis occurs prenatally. Vulnerable to smoking, alcohol, diet, and exercise.

Adaptation (Assimilation and Accommodation)

Adaptation comprises assimilation (interpreting new experiences based on present world views) and accommodation (adjusting existing thought structures).

Sensorimotor Stage (0 to 2 years)

Children predominantly learn through sensory input and movement, transitioning from reflexes to voluntary exploration.

Preoperational Stage (2 to 7 years)

Marked by use of symbols (language, pretend play), egocentrism, transductive reasoning, and inability to logically manipulate information.

Concrete Operational Stage (7 to 12 years)

Involves mastering tangible logic, inductive reasoning, and the ability to modify, organize, or reverse thoughts.

Formal Operational Stage (12+ years)

Understanding abstract principles, hypothetical-deductive reasoning, and adolescent egocentrism/personal fable.

Criticisms of Piaget's Theory

Lacked scientific control, used his own children, underestimated children, and lacked a lifespan orientation.

Postformal Operations

Stage beyond formal operations featuring realistic/practical decisions and dialectical thought.

Neuron Specialization

Neurons are genetically identical but differ in structure, specializing depending on their environment.

Gene Regulation in Neurons

Neural signals determine whether certain genes go on and off.

Neuron Migration & Differentiation

Developed neurons migrate and differentiate, steered by growth factors like glial cells.

Axon Terminal

The end of an axon that helps transmit signals to adjoining cells.

Smoking and Neuron Migration

Smoking can affect the migration of neurons, leading to learning difficulties.

Neuron Migration

The movement of newly formed neurons to their permanent destinations in the developing brain.

Alcohol and Neuron Migration

Disrupts neuron migration, leading to lower child IQ and learning difficulties.

Spinal cord and lower brain centres at birth

More developed relative to higher centers at birth. Due to food intake/respiration.

Neuronal growth and arborisation

Neurons increase in size, differentiation continues, and prolific arborisation and synaptogenesis occurs.

Apoptosis and synaptic pruning

Critical period as neurons and synapses compete for growth factors.

Postnatal Brain Weight Milestones

The brain is 25% of adult weight at birth, reaching 80% by age 4.

Mechanism of Postnatal Brain Growth

Driven by changes in the size of neurons and the complexity of synapses.

Arborisation

The extensive branching of dendrites, increasing the neuron's surface area to receive more signals.

Synaptogenesis

The formation of billions of new synapses between neurons, establishing functional neural circuits.

Significance of Arborisation and Synaptogenesis

Massively increases neural connectivity and network complexity during early brain development.

Synapses per Neuron

A new neuron forms between 10,000 and 100,000 synapses with other neurons.

Frequently Used Synapses

Frequent use causes physical changes, making pre- and post-synaptic neurons grow closer together and become more efficient.

Synapse Development in Adolescence

The density and complexity of synapses increases.

Adolescent Myelination

Increased myelination makes the transmission of sensory and motor neural messages more efficient.

Prefrontal Cortex Development

Develops throughout adolescence, is involved in impulse control, and is not fully developed until age 20.

Early Adulthood Nervous System

Early adulthood sees the peak of nervous system performance.

What happens to most brain regions in older adulthood?

Most brain regions shrink by approximately 0.5% per annum.

What type of brain matter is lost in older adulthood?

Grey matter is removed.

What type of brain matter is held in older adulthood?

White matter is held.

What causes brain shrinkage in older adulthood?

Loss of neuron complexity.

Jean Piaget

A Swiss psychologist renowned for his theory of cognitive development in children.

Jean Piaget Critique

Adolescence finished cognitive development.

Adaptation

Processes of adjusting to environment via reasoning.