Human Growth

The 'use it or lose it' principle states that failure to use neural networks can lead to degradation of functions and learned non-use, requiring environments to be set up for increased engagement and stimulation.

The 'use it to improve it' principle suggests that training or usage can maintain networks and connections, driving alternate processes and protecting plasticity.

According to the specificity principle, the nature of training dictates the nature of plasticity, and mere use is not enough for strengthening synaptic connections.

Repetition, intensity, timing, and salience all matter in inducing plasticity. Early intervention is critical because age, transference, and interference all play roles in inducing plasticity and acquiring new skills.

Developmental system perspectives and the lifespan perspective are important for understanding human development because they involve changing relations between the developing person and multi-level environmental contexts, and can impact short and long-term health outcomes.

Growth involves changes in quantity and body size, with body proportions varying with age and impacting developmental motor control.

Growth cones play a critical role in guiding axons to appropriate targets via signaling mechanisms. They are responsible for the navigation of developing axons to their specific targets, ensuring the proper formation of neural circuits.

Disruptions in neural induction and neurogenesis can lead to congenital conditions such as spina bifida, anencephaly, fetal alcohol syndrome, and hydrocephalus. These disruptions can result in incomplete neural tube closure, abnormal brain development, and cognitive impairments.

Neurotrophic influences play a crucial role in determining the establishment and modification of neural circuits. They regulate the survival and growth of neurons, as well as the formation and refinement of synaptic connections.

Critical periods exist for activity-mediated influence, with neurotransmitter activity and receptor sensitivity playing crucial roles. During these critical periods, neural circuits are particularly susceptible to the effects of experience, which can have lasting impacts on behavior and cognitive abilities.

Myelination increases into the late teens and early twenties, partly explaining behavioral changes and increased cognitive abilities during this period. The development of myelin sheaths around axons improves the efficiency of neural signaling and contributes to cognitive and motor skill improvements.

The cerebellum plays a crucial role in motor control, particularly in fine-tuning and planning movements. It compares intended output with sensory signals to adjust and update movement commands, essential for coordinated and precise movements.

Genetics, environment, diet, and physical activity are important factors that influence human growth and development.

The distinct periods of human development include prenatal, infancy, early childhood, later childhood, adolescence, adulthood, and older age. Each period is characterized by specific biological events and developmental milestones.

Trauma and adverse childhood experiences can impact physical, cognitive, social, and emotional development. They can lead to neurobiological changes, altered neural systems, and sensitization to stress, affecting learning, concentration, and the ability to regulate behavior and emotions.

Various theories of human development include psychoanalytic, cognitive, behavioral, and ethological theories. Attachment theory emphasizes the importance of forming emotional attachments to caregivers for survival.

The phases of attachment according to attachment theory include pre-attachment, attachment in the making, clear-cut attachment, and the formation of a reciprocal relationship. These phases impact the individual's future close relationships and parenting styles.

Factors that affect attachment security include opportunity for attachment, quality of caregiving, and infant characteristics. Trauma and adverse childhood experiences can also impact attachment security, which in turn can affect physical, cognitive, social, and emotional development.

Neuroplasticity refers to the nervous system's ability to change or modify, involving shorter-term changes in synaptic connections and longer-term structural changes in the organization and numbers of connections among neurons. It impacts motor learning and control by enabling functional reorganization and changes in cortical maps in response to activity, behavior, and skill acquisition.

The basal ganglia, mediated by dopamine, play a role in motor learning and goal-directed behavior by working with the motor cortex to plan, select, and execute movement. Dopamine facilitates the communication between the basal ganglia and cerebral hemispheres, contributing to the coordination and execution of motor tasks.

Movement control involves subconscious planning and organization by the motor cortex and cerebellum, with feedback from peripheral sensory receptors. The motor cortex and cerebellum play essential roles in organizing and coordinating movements, while peripheral sensory receptors provide feedback to adjust and refine the movements.

The brain organizes movement differently based on task attributes like discrete vs continuous tasks, stability vs mobility tasks, manipulation continuum, and attention continuum. These task attributes influence the neural mechanisms and pathways involved in planning and executing movements, shaping the organization of movement in the brain.

Functional reorganization at the network or systems level involves changes in cortical maps and the development of new functions in response to sensory input and motor demands. This process enables the brain to adapt and reorganize its neural pathways and functions to meet the changing sensory and motor requirements.

The demand-driven nature of the nervous system leads to competition that determines the domination of neural borders and functional areas in the brain. This competition influences the allocation of neural resources and the development of specialized functional areas in response to the demands placed on the nervous system.

Early development of the nervous system involves the establishment of the embryonic nervous system, formation of major brain regions, generation of neurons from undifferentiated cells, migration of neurons to final positions, formation of axon pathways, and synaptic connections. The two main processes are gastrulation, which involves the generation of cell layers to define the axes of development, and neurulation, which gives rise to the entire nervous system.

The two processes involved in the formation of the nervous system are gastrulation and neurulation. Gastrulation involves the generation of layers of cells to define the axes of development, including the formation of the notochord. Neurulation gives rise to the entire nervous system, starting from the ectoderm above the notochord, leading to the formation of the neural tube, brain, spinal cord, and most of the peripheral nervous system.

The four stages of neural development are neurogenesis, cell migration, cell differentiation, and synaptogenesis. Neurogenesis involves the proliferation of neural cells, occurring in the embryo. Cell migration follows to establish distinct cell populations. Cell differentiation refers to the process in which precursor cells differentiate into neurons, astrocytes, and oligodendroglia. Finally, synaptogenesis involves the formation of synaptic connections between neurons.

During neural development, molecular signals play a crucial role in specifying the final position and cell type for precursor cells. These signals, relative to the original position, help to develop a head and tail end, and genetically determine neural induction. Migration then allows cells to reach their specified positions, contributing to the formation of distinct cell populations.

Neurulation involves the ectoderm above the notochord giving rise to the entire nervous system, leading to the formation of the neural tube, brain, spinal cord, and most of the peripheral nervous system. The key events include the development of the neural plate, closure of the fold to form the neural tube, and the concentration of neurons at one end to form the brain.

During neural development, precursor cells differentiate into neurons, astrocytes, and oligodendroglia. Molecular signals play a crucial role in specifying the final position and type for these cells, relative to their original position. This differentiation is also genetically determined through neural induction and migration to reach specified positions.

The cerebral hemispheres play a role in motor learning and goal-directed behavior through the basal ganglia, which is mediated by dopamine.

The motor cortex and basal ganglia work together to plan, select, and execute movement, with the motor cortex being the major output pathway for voluntary movement.

Movement emerges from the interaction of task, environment, and individual factors that constrain movement, such as action, perception, and cognition.

The taxonomy of environment includes regulatory features that directly shape movement and non-regulatory features that indirectly cause changes to movement.

Neuroplasticity is the nervous system's ability to change or modify, involving shorter-term changes in synaptic connections and longer-term structural changes in the organization and numbers of connections among neurons.

Recovery from brain injury involves processes such as denervation super-sensitivity, synaptic hyper-effectiveness, and regenerative synaptogenesis in both the peripheral and central nervous systems.

The two processes involved in the formation of the nervous system are gastrulation and neurulation.

The four stages of neural development are neurogenesis, cell migration, cell differentiation, and synaptogenesis.

The key points about early development of the nervous system are the establishment of the embryonic nervous system, formation of major brain regions, generation of neurons from undifferentiated cells, migration of neurons to final positions, and subsequent formation of axon pathways and synaptic connections.

Molecular signals specify the final position and type for precursor cells (stem cells) during neural development.

The two processes involved in the formation of layers of cells and the ultimate axes of development in the nervous system are gastrulation and neurulation.

Neurulation gives rise to the entire nervous system, including the neural tube, brain, spinal cord, and most of the peripheral nervous system.