The development of brain circuits is a complex process influenced by genetic, environmental, and neuroplastic factors. Neural circuits in the cerebral cortex, responsible for functions like visual processing, attention, memory, and cognitive control, develop through interconnected anatomical regions. This development is shaped by genetic predispositions, environmental events, and neuroplastic responses that modulate connectivity and communication among neurons. Recent advances in neuroimaging and computational neurobiology, along with traditional methods like histological studies and cellular biology, have enhanced understanding of these processes in humans. Neural circuits begin developing early in gestation, with the neural tube forming at GA weeks 2–3. By GA week 8, neuroblasts differentiate into neurons or glial cells, and by GA week 12–20, neurons migrate to form cortical layers. Synaptic connections form early, with the preplate and subplate serving as transient structures. The subplate, which is rich in synapses, eventually dissolves as the cortical plate matures, allowing for more stable connections. The cortical plate develops into distinct layers, with lamination beginning in primary sensory and motor cortices by GA week 25. By GA week 32, the cortex has a full adult complement of laminae, containing afferents from all major neurotransmitter systems. Cortical laminae have distinct cell types and connections, forming functional circuits. For example, layer VI contains pyramidal cells that project to the thalamus, while layer IV is the primary target for thalamic inputs. Synaptogenesis peaks around GA weeks 26–28, with synaptic density increasing rapidly. Synaptic pruning begins in late gestation and continues postnatally, with sensory and motor cortices undergoing dramatic fine-tuning. Myelination follows, with sensory pathways myelinating first, followed by motor pathways and association areas. Myelination continues into early childhood, with the frontal lobes myelinating between 7 and 11 months. Functional imaging studies show that metabolic activity increases in specific brain regions as the infant develops. Functional connectivity methods reveal distinct networks in neonates, including visual, sensorimotor, and auditory processing networks, as well as a prefrontal network. These networks are associated with intrinsic spontaneous brain activity and are linked to abstract and autobiographical processing. Infant behavior reflects the maturation of neural circuits, with complex, disorganized movements and reflexive eye saccades. Behavioral changes in the third postnatal month, such as inhibitory control and goal-directed behaviors, correspond to cortical remodeling and myelination of association areas. Hand-to-hand transfer around 6 months of age reflects increasing coordination among sensory, motor, and association circuits. The developing brain is vulnerable to harmful exposures, including toxins, drugs, nutritional deficiencies, and environmental stressors. Early separation from caregivers, abuse, neglect, or social deprivation can lead to enduring behavioral and neurocognitive deficits. EarlyThe development of brain circuits is a complex process influenced by genetic, environmental, and neuroplastic factors. Neural circuits in the cerebral cortex, responsible for functions like visual processing, attention, memory, and cognitive control, develop through interconnected anatomical regions. This development is shaped by genetic predispositions, environmental events, and neuroplastic responses that modulate connectivity and communication among neurons. Recent advances in neuroimaging and computational neurobiology, along with traditional methods like histological studies and cellular biology, have enhanced understanding of these processes in humans. Neural circuits begin developing early in gestation, with the neural tube forming at GA weeks 2–3. By GA week 8, neuroblasts differentiate into neurons or glial cells, and by GA week 12–20, neurons migrate to form cortical layers. Synaptic connections form early, with the preplate and subplate serving as transient structures. The subplate, which is rich in synapses, eventually dissolves as the cortical plate matures, allowing for more stable connections. The cortical plate develops into distinct layers, with lamination beginning in primary sensory and motor cortices by GA week 25. By GA week 32, the cortex has a full adult complement of laminae, containing afferents from all major neurotransmitter systems. Cortical laminae have distinct cell types and connections, forming functional circuits. For example, layer VI contains pyramidal cells that project to the thalamus, while layer IV is the primary target for thalamic inputs. Synaptogenesis peaks around GA weeks 26–28, with synaptic density increasing rapidly. Synaptic pruning begins in late gestation and continues postnatally, with sensory and motor cortices undergoing dramatic fine-tuning. Myelination follows, with sensory pathways myelinating first, followed by motor pathways and association areas. Myelination continues into early childhood, with the frontal lobes myelinating between 7 and 11 months. Functional imaging studies show that metabolic activity increases in specific brain regions as the infant develops. Functional connectivity methods reveal distinct networks in neonates, including visual, sensorimotor, and auditory processing networks, as well as a prefrontal network. These networks are associated with intrinsic spontaneous brain activity and are linked to abstract and autobiographical processing. Infant behavior reflects the maturation of neural circuits, with complex, disorganized movements and reflexive eye saccades. Behavioral changes in the third postnatal month, such as inhibitory control and goal-directed behaviors, correspond to cortical remodeling and myelination of association areas. Hand-to-hand transfer around 6 months of age reflects increasing coordination among sensory, motor, and association circuits. The developing brain is vulnerable to harmful exposures, including toxins, drugs, nutritional deficiencies, and environmental stressors. Early separation from caregivers, abuse, neglect, or social deprivation can lead to enduring behavioral and neurocognitive deficits. Early