The Impact of Attachment (Norton Series on Interpersonal Neurobiology) by Susan Hart

Author:Susan Hart
Language: eng
Format: epub
Publisher: W. W. Norton & Company
Published: 2006-05-04T16:00:00+00:00

The Impact of Dysregulation on Brain Development

As mentioned earlier, adult monkeys raised by mothers that were unable to provide appropriately stable, attuned, and predictable contact show lifelong changes in neurotransmitters such as noradrenaline, serotonin, and dopamine. These changes cause them to lose their capacity to modulate aggression, and they become erratic, unpredictable, chaotic, and vicious (Lewis et al., 2001). The brain’s circuits are shaped through a natural selection of connections that match environmental data. In the early caregiver-child contact the child attunes with the caregiver’s dysregulated state, which is incorporated into the child’s nervous system. For example, if the child is in a chronic stress state, synaptic connections are reduced in number, which leads to an ineffective regulation of the autonomic nervous system and its interactions with higher centers, including the limbic system and the orbitofrontal cortex. The self-regulation of the nervous system becomes unstable, and its capacity for change and development later in life is reduced. The dominance of subcortical activity may prolong protest and rage responses or cause extreme passivity and depression (Schore, 1994, 2002).

As mentioned earlier, disturbances in neurochemical signals during infancy may stem either from inadequate care (deprivation) or abuse. Inadequate and dysfunctional stimulation impairs the necessary pruning and specialization of neurons and neural circuits, which in turn impairs the capacity to organize experiences. Abuse may activate the anxiety response, which causes the child’s nervous system to dissociate. Both abuse and deprivation have an almost invisible toxic effect on a developing nervous system. For example, a child who is exposed to abuse develops an alarm response that alters the structure and functions of the brain to form adaptive responses to survival-related information. Even if the alarm response facilitates survival, chronic stress experiences cause the nervous system to become either hyper-or hyporeactive. This leads to exaggerated or diminished alertness, causes the startle response to activate more quickly than normal or not at all, and leads to affect lability, anxiety, and so on. The earlier and the more extensive the abuse, the more severe the consequences for the child’s development, and the bigger the risk that the child will have difficulty developing self-regulation strategies. A neural system that activates frequently practices responding to certain stimuli, just as practicing the piano serves to mature the neural circuits involved in playing it. The more threat-related behavior the child experiences, the more activation there is of the neural systems involved in overcoming this type of experience. The degree and nature of specific responses will vary from person to person (Perry, 2001; Perry et al., 1995; Schwarz & Perry, 1994).

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