Neural Development and Neuroplasticity in childhood Flashcards
Early Language Development
By 4 years old, children have a good command of language (phonology, semantics, syntax, pragmatics) but do not yet read or do mathematical calculations.
Genetic basis for language
Language has a genetic foundation, but exposure is required for development. Genes create proteins
Neurogenesis
The birth of new neurons. All neurons are formed at birth and positioned within the six layers of the cortex.
Neural Proliferation (3-4 months gestation)
Neurons and glia form; neurons first develop in the spinal cord and brainstem, then around ventricles, then into gray and white matter of the cerebral hemispheres.
Microcephaly
A condition resulting from interrupted neurogenesis, leading to abnormally small heads/brains. Causes include viruses (e.g., Zika) and alcohol exposure in the womb. Symptoms include intellectual disability, speech/language impairment, and sensory/motor impairment.
Neural Migration (3-5 months gestation)
Neurons migrate to their designated places in the brain with the help of radial glia cells. By 5 months gestation, migration is complete, and the six layers of the cerebral cortex are established.
Scizencephaly
A condition caused by improper cell migration, resulting in clefts in the cerebral hemispheres.
Lissencephaly
A smooth brain lacking characteristic sulci and gyri due to the chemical reelin malfunctioning. Symptoms include speech-language impairments, intellectual disability, and developmental delays.
Neural Development (5 months gestation- postnatal)
Neurons sprout dendrites and axons, synaptogenesis begins, and myelination starts at 6 months gestation, peaking around 1 year after birth.
Hypomyelination
A reduced ability to form myelin, causing symptoms such as intellectual disability, paralysis, muscle atrophy, neuropathy, cataracts, and dysarthria.
Brain Neuroplasticity
Neurons that fire together wire together; neurons that do not connect delink. Synaptogenesis peaks in different brain regions at different times, allowing rapid learning.
Early Language Milestones
- Newborn: Reflexive behaviors
- ~3 months: Cooing
- ~4 months: Recognizes their name
- ~6 months: Babbling (native language-like)
- ~8 months: Word forms are encoded in the brain
- ~10 months: Understands some words (e.g., “wave bye-bye”)
- ~1 year: Says first words
- ~18 months - 2 years: Combines two words
Motor Milestones
- ~2 months: Holds head up (wobbly)
- ~4 months: Holds head up, sits with support
- ~6 months: Sits
- ~8 months: Crawls
- ~1 year: First steps
Neural motor development for speech
Requires head and torso support along with isolated articulator muscle movements.
Neural pathways and speech learning
Pathways formed in infancy and childhood support learning, including speech and language.
Infant brain development
Neurons sprout dendrites and axons, synaptogenesis occurs, excess synapses are pruned over time.
Neural Pathways at Birth
- Dorsal Pathway (pSTG to BA 6): Supports babbling and sound production
- Ventral Pathway (ATL to BA 45 & BA 47): Supports early word learning
- Ventral Pathway (ATL to Frontal Operculum): Supports early language processing
- Superior Longitudinal Fasciculus/Arcuate Fasciculus: Not formed at birth, supports word/sentence repetition and syntax
Fetal Behavior development
- 10-12 weeks gestation: Flexion/extension of trunk, reflexes emerge
- 12 weeks gestation: Head and limb movements begin
- Second trimester: Facial and head behaviors emerge
- Third trimester: Movements become more coordinated
Adolescent Brain Development
- Adolescence begins around 10-12 years.
- Profound brain development continues until age 25.
- Synaptic pruning moves from the back of the brain to the prefrontal cortex.
- The prefrontal cortex is the last area to mature.
- Adolescents rely more on emotions and impulses due to ongoing prefrontal cortex development.
Cortical Organization (5 months gestation- postnatal)
- Neurons migrate to their intended brain region and layer.
- Synaptogenesis forms synapses between neurons.
- Synaptic pruning eliminates unnecessary connections.
- Mature behaviors use smaller brain volume and networks.
