To understand how maltreatment can affect a child's neurological development, it is important to first understand that the brain is organized into and develops within four distinct regions. These regions range from least to most complex, and each region develops, organizes, and becomes fully functional at different stages of a child's development.
One of the more critical functions of the lower, or "micro-level," brain regions is the creation of neural networks that facilitate simultaneous communication across the regions. Impairment of these neural networks can result in a myriad of dysfunctions that extend from the lower regions to the higher, or "macro-level," regions. Thus, brain development in the higher regions that control functions like perception, reasoning, emotion, and problem-solving is dependent on development in the lower regions.
Many of the micro-level brain processes, including the critical development of neural networks, are dependent on an optimal level of activation, which in part comes from the environment or experience of the child. When the child has adverse experiences, such as loss, threat, neglect, or abuse, the brain’s developmental processes can be disrupted in the micro-level areas and the neural connections can wither. This, in turn, can have a cascading negative effect on the macro-level regions of the brain. Depending on the degree and duration of the adverse experience, these effects can be significant and hamper the child’s functioning well into adulthood.
Early childhood, during which neurons are organized to form the complex workings of the brain, is a critical time for brain development. This development includes essential neurological processes that establish patterns of behavioral and emotional functioning during subsequent stages of life. Since a child's early experiences and environment can significantly affect the development of specific areas of the brain, the impact of neglect and the impact of abuse on a child's brain can seriously affect his or her ability to regulate emotions and become emotionally connected with others in the future.
Impact of Neglect
Whether it is a lack of emotional or physical nurturance, neglect can negatively affect the child's neurological development. If a caregiver is depressed, chronically stressed, inconsistent, or absent, this can adversely affect the brain’s neural networks that help the child to regulate stress and benefit from healthy, nurturing support. Essentially, these early experiences between the caregiver and child create a template for the child’s brain, setting up associations that help determine the child’s balance between resilience and vulnerability. Bonding and healthy caregiver/child interaction are critical in ensuring normal brain development; thus, the negative impact of neglect on the developing brain, beginning in the lower regions and expanding into the higher regions, can significantly impede a child’s ability to develop socially and emotionally, and to meet developmental milestones.
For example, one of an infant's primary tasks is to determine how to have his or her needs met. Infants constantly assess whether their cries for comfort and food are answered or ignored. When infants feel safe and secure and their needs for food and soothing are met, their brains are free to explore, focus on the objects and people in the world around them, and develop socially and cognitively. If, however, responses to them are inconsistent or harsh, infants will concentrate their energy and brainwork on survival or ensuring that their needs are met. As a result, it becomes increasingly difficult for them to interact with surrounding people and objects, as their mental and emotional resources are focused on other tasks and their brains shut out the stimulation needed to develop healthy cognitive and social skills.
Impact of Abuse
Abuse, like neglect, can severely affect a child's neurological development. While mild or moderate levels of stress for a child within a supportive and nurturing environment can promote adaptive coping skills, abuse or severe neglect can expose children to chronic and abnormal levels of stress, which in turn can lead to elevated levels of cortisol, a stress hormone. These levels can become toxic and stunt the tissue growth of the hippocampus, an area of the brain that affects the child’s ability to respond to future stress, regulate emotion, and retain memory.
Heightened stress can also impede the development of the prefrontal cortex, a part of the brain that controls critical functions like focusing, planning, self-regulation, and decision-making. All of these functions are essential for children to successfully navigate their way later in life, academically, in relationships, and in the workplace.